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Wei X, Gao J, Zhou D, Xu C, Chen P, Chen S, Zhang Y, Liu X, Li G, Zhu G, Liu H, Li J, Geng B, Gao L, Cheng Z, Lamont IL, Pletzer D, Jin Y, Jin S, Wu W. Murepavadin promotes the killing efficacies of aminoglycoside antibiotics against Pseudomonas aeruginosa by enhancing membrane potential. Antimicrob Agents Chemother 2024; 68:e0153923. [PMID: 38470195 PMCID: PMC10989017 DOI: 10.1128/aac.01539-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/19/2024] [Indexed: 03/13/2024] Open
Abstract
Murepavadin is a peptidomimetic that specifically targets the lipopolysaccharide transport protein LptD of Pseudomonas aeruginosa. Here, we found that murepavadin enhances the bactericidal efficacies of tobramycin and amikacin. We further demonstrated that murepavadin enhances bacterial respiration activity and subsequent membrane potential, which promotes intracellular uptake of aminoglycoside antibiotics. In addition, the murepavadin-amikacin combination displayed a synergistic bactericidal effect in a murine pneumonia model.
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Affiliation(s)
- Xiaoya Wei
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jiacong Gao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Dandan Zhou
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Congjuan Xu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Ping Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Shuiping Chen
- Department of Laboratory Medicine, 5th Medical Center of PLA General Hospital, Beijing, China
| | - Yanhong Zhang
- Nankai University Affiliated Hospital (Tianjin Forth Hospital), Tianjin, China
| | - Xuehua Liu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Guanxian Li
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Guangbo Zhu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Huimin Liu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Jinjin Li
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Bin Geng
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Linlin Gao
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Iain L. Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
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Rajchakit U, Lamba S, Wang K, Lyons N, Lu J, Swift S, Pletzer D, Sarojini V. Size-Controlled Synthesis of Gold Nanoparticles Tethering Antimicrobial Peptides with Potent Broad-Spectrum Antimicrobial and Antibiofilm Activities. Mol Pharm 2024; 21:596-608. [PMID: 38190605 DOI: 10.1021/acs.molpharmaceut.3c00734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
New antimicrobials are urgently needed to combat the rising global health concern of antibiotic resistance. Antimicrobial peptides (AMPs) are one of the leading candidates as new antimicrobials since they target bacterial membranes and are therefore less prone to bacterial resistance. However, poor enzymatic stability, high production costs, and toxicity are drawbacks that limit their clinical use. Conjugation of AMPs to gold nanoparticles (NPs) may help to improve enzymatic stability and, thus, their overall antimicrobial efficiency. We did a one-pot synthesis of size-controlled (10 nm) gold NPs selectively conjugated to lipopeptides and determined their antibacterial activity. The conjugates exhibited potent (0.13-1.25 μM) antimicrobial activity against clinical isolates, including Gram-positive methicillin-resistant Staphylococcus aureus (S. aureus) ATCC33593, Gram-negative Escherichia coli (E. coli) CTX-M-14, multidrug-resistant Pseudomonas aeruginosa LESB58 and Acinetobacter baumannii ATCC19606, and showed promising activity (90% inhibition of initial biofilms and 80% reduction of preformed biofilms) against S. aureus and E. coli DH5α biofilms at low micromolar concentrations. The conjugates were stable in rat serum and not toxic to representative mammalian cell lines in vitro (≤64 μM) and in vivo (≤100 μM).
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Affiliation(s)
- Urawadee Rajchakit
- School of Chemical Sciences and The Centre for Green Chemical Science, University of Auckland, Auckland 1142, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6012, New Zealand
| | - Saurabh Lamba
- School of Chemical Sciences and The Centre for Green Chemical Science, University of Auckland, Auckland 1142, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6012, New Zealand
| | - Kelvin Wang
- Auckland Bioengineering Institute, University of Auckland, Auckland 1142, New Zealand
| | - Nikita Lyons
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Jun Lu
- Auckland Bioengineering Institute, University of Auckland, Auckland 1142, New Zealand
| | - Simon Swift
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Vijayalekshmi Sarojini
- School of Chemical Sciences and The Centre for Green Chemical Science, University of Auckland, Auckland 1142, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6012, New Zealand
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Saha T, Lyons N, Yue Yung DB, Quiñones-Mateu ME, Pletzer D, Das SC. Repurposing ebselen as an inhalable dry powder to treat respiratory tract infections. Eur J Pharm Biopharm 2024; 195:114170. [PMID: 38128743 DOI: 10.1016/j.ejpb.2023.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 12/11/2023] [Accepted: 12/17/2023] [Indexed: 12/23/2023]
Abstract
Respiratory tract infections (RTIs) are one of the leading causes of death globally, lately exacerbated by the increasing prevalence of antimicrobial resistance. While antimicrobial resistance could be overcome by developing new antimicrobial agents, the use of a safe repurposed agent having potent antimicrobial activity against various RTIs can be an efficient and cost-effective alternative to overcome the long and complex process of developing and testing new drugs. Ebselen, a synthetic organoselenium drug originally developed to treat noise-inducing hearing problems, has shown promising antimicrobial activity in vitro against several respiratory pathogens including viruses (e.g., SARS-CoV-2, influenza A virus) and bacteria (e.g., Mycobacterium tuberculosis, Streptococcus pneumoniae, and Staphylococcus aureus). Inhaled drug delivery is considered a promising approach for treating RTIs, as it can ensure effective drug concentrations at a lower dose, thereby minimizing the side effects that are often encountered by using oral or injectable drugs. In this study, we developed inhalable ebselen dry powder formulations using a spray-drying technique. The amino acids leucine, methionine, and tryptophan were incorporated with ebselen to enhance the yield and aerosolization of the dry powders. The amino acid-containing ebselen dry powders showed a better yield (37-56.4 %) than the amino acid-free formulation (30.9 %). All dry powders were crystalline in nature. The mass median aerodynamic diameter (MMAD) was less than 5 µm for amino acids containing dry powders (3-4 µm) and slightly higher (5.4 µm) for amino acid free dry powder indicating their suitability for inhalation. The aerosol performance was higher when amino acids were used, and the leucine-containing ebselen dry powder showed the highest emitted dose (84 %) and fine particle fraction (68 %). All amino acid formulations had similar cytotoxicity as raw ebselen, tested in respiratory cell line (A549 cells), with half-maximal inhibitory concentrations (IC50) between 100 and 250 μg/mL. Raw ebselen and amino acid-containing dry powders showed similar potent antibacterial activity against the Gram-positive bacteria S. aureus and S. pneumoniae with minimum inhibitory concentrations of 0.31 μg/mL and 0.16 μg/mL, respectively. On the other hand, raw ebselen and the formulations showed limited antimicrobial activity against the Gram-negative pathogens Pseudomonas aeruginosa and Klebsiella pneumoniae. In summary, in this study we were able to develop amino-acid-containing inhalable dry powders of ebselen that could be used against different respiratory pathogens, especially Gram-positive bacteria, which could ensure more drug deposition in the respiratory tract, including the lungs. DPIs are generally used to treat lung (lower respiratory tract) diseases. However, DPIs can also be used to treat both upper and lower RTIs. The deposition of the dry powder in the respiratory tract is dependent on its physicochemical properties and this properties can be modulated to target the intended site of infection (upper and/or lower respiratory tract). Further studies will allow the development of similar formulations of individual and/or combination of antimicrobials that could be used to inhibit a number of respiratory pathogens.
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Affiliation(s)
- Tushar Saha
- School of Pharmacy, University of Otago, Dunedin, New Zealand
| | - Nikita Lyons
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Deborah Bow Yue Yung
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Miguel E Quiñones-Mateu
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Daniel Pletzer
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Shyamal C Das
- School of Pharmacy, University of Otago, Dunedin, New Zealand.
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Choudhury M, Brunton P, Schwass D, Pletzer D, Ratnayake J, Dias G, Tompkins G. Effectiveness of gold nanoparticles in prevention and treatment of oral mucositis in animal models: a systematic review. Syst Rev 2024; 13:39. [PMID: 38273391 PMCID: PMC10809540 DOI: 10.1186/s13643-023-02425-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 12/08/2023] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Oral mucositis remains a significant complication during cancer therapy with no effective treatment. Gold nanoparticles offer anti-inflammatory, antioxidant properties with low toxicity. This study systematically reviews the literature assessing gold nanoparticles in the management of oral mucositis in animal models. METHODS A literature search was undertaken using MEDLINE, Embase, PubMed, and Web of Science databases, using the format for Systematic Review Centre for Laboratory Animal Experimentation. Prior to the review, the protocol was registered in the systematic review register, PROSPERO (registration no. CRD42021272169). Outcome measures included ulceration, histopathological scores, inflammatory mediators, microbial growth, and pain. Study quality was analysed by SYRCLE risk-of-bias tool. RESULTS Only one study met the inclusion criteria, documenting reduction in ulceration, inflammatory, and oxidative biomarkers. Exposure to AuNPs prevented inflammatory response induced by 5-fluorouracil in oral mucosa of hamsters. However, a high risk of bias necessitates further research. CONCLUSION This review identifies a potential therapeutic strategy for prevention and management of oral mucositis. It also provides future direction for gold nanoparticle research in oral mucositis; however, there is lack of sufficient evidence to derive any conclusion. Research with standardized parameters including nanoparticle size, capping agent, surface charge, and appropriate oral mucositis animal models will establish risk-benefit balance and margin of safety for therapeutic use of gold nanoparticles for oral mucositis.
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Affiliation(s)
- Minati Choudhury
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
- Restorative Dentistry, School of Dentistry, International Medical University, Kuala Lumpur, Malaysia.
| | - Paul Brunton
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
- DVCA, Curtin University, Perth, Australia
| | - Donald Schwass
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
| | - Jithendra Ratnayake
- Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - George Dias
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Geoffrey Tompkins
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
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5
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Fahma F, Firmanda A, Cabral J, Pletzer D, Fisher J, Mahadik B, Arnata IW, Sartika D, Wulandari A. Three-Dimensional Printed Cellulose for Wound Dressing Applications. 3D Print Addit Manuf 2023; 10:1015-1035. [PMID: 37886399 PMCID: PMC10599445 DOI: 10.1089/3dp.2021.0327] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Wounds are skin tissue damage due to trauma. Many factors inhibit the wound healing phase (hemostasis, inflammation, proliferation, and alteration), such as oxygenation, contamination/infection, age, effects of injury, sex hormones, stress, diabetes, obesity, drugs, alcoholism, smoking, nutrition, hemostasis, debridement, and closing time. Cellulose is the most abundant biopolymer in nature which is promising as the main matrix of wound dressings because of its good structure and mechanical stability, moisturizes the area around the wound, absorbs excess exudate, can form elastic gels with the characteristics of bio-responsiveness, biocompatibility, low toxicity, biodegradability, and structural similarity with the extracellular matrix (ECM). The addition of active ingredients as a model drug helps accelerate wound healing through antimicrobial and antioxidant mechanisms. Three-dimensional (3D) bioprinting technology can print cellulose as a bioink to produce wound dressings with complex structures mimicking ECM. The 3D printed cellulose-based wound dressings are a promising application in modern wound care. This article reviews the use of 3D printed cellulose as an ideal wound dressing and their properties, including mechanical properties, permeability aspect, absorption ability, ability to retain and provide moisture, biodegradation, antimicrobial property, and biocompatibility. The applications of 3D printed cellulose in the management of chronic wounds, burns, and painful wounds are also discussed.
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Affiliation(s)
- Farah Fahma
- Department of Agroindustrial Technology, Faculty of Agricultural Engineering and Technology, IPB University (Bogor Agricultural University), Bogor, Indonesia
| | - Afrinal Firmanda
- Department of Agroindustrial Technology, Faculty of Agricultural Engineering and Technology, IPB University (Bogor Agricultural University), Bogor, Indonesia
| | - Jaydee Cabral
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand
| | - Daniel Pletzer
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand
| | - John Fisher
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
| | - Bhushan Mahadik
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
| | - I Wayan Arnata
- Department of Agroindustrial Technology, Faculty of Agricultural Technology, Udayana University, Badung, Indonesia
| | - Dewi Sartika
- Faculty of Agriculture, Muhammadiyah University of Makassar, Makassar, Indonesia
| | - Anting Wulandari
- Department of Agroindustrial Technology, Faculty of Agroindustrial Technology, Padjadjaran University, Bandung, Indonesia
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6
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Wei X, Gao J, Xu C, Pan X, Jin Y, Bai F, Cheng Z, Lamont IL, Pletzer D, Wu W. Murepavadin induces envelope stress response and enhances the killing efficacies of β-lactam antibiotics by impairing the outer membrane integrity of Pseudomonas aeruginosa. Microbiol Spectr 2023; 11:e0125723. [PMID: 37668398 PMCID: PMC10581190 DOI: 10.1128/spectrum.01257-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 07/08/2023] [Indexed: 09/06/2023] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen that can cause a variety of acute and chronic infections. The bacterium is highly resistant to numerous antibiotics. Murepavadin is a peptidomimetic antibiotic that blocks the function of P. aeruginosa lipopolysaccharide (LPS) transport protein D (LptD), thus inhibiting the insertion of LPS into the outer membrane. In this study, we demonstrated that sublethal concentrations of murepavadin enhance the bacterial outer membrane permeability. Proteomic analyses revealed the alteration of protein composition in bacterial inner and outer membranes following murepavadin treatment. The antisigma factor MucA was upregulated by murepavadin. In addition, the expression of the sigma E factor gene algU and the alginate synthesis gene algD was induced by murepavadin. Deletion of the algU gene reduces bacterial survival following murepavadin treatment, indicating a role of the envelope stress response in bacterial tolerance. We further demonstrated that murepavadin enhances the bactericidal activities of β-lactam antibiotics by promoting drug influx across the outer membrane. In a mouse model of acute pneumonia, the murepavadin-ceftazidime/avibactam combination showed synergistic therapeutic effect against P. aeruginosa infection. In addition, the combination of murepavadin with ceftazidime/avibactam slowed down the resistance development. In conclusion, our results reveal the response mechanism of P. aeruginosa to murepavadin and provide a promising antibiotic combination for the treatment of P. aeruginosa infections.IMPORTANCEThe ever increasing resistance of bacteria to antibiotics poses a serious threat to global public health. Novel antibiotics and treatment strategies are urgently needed. Murepavadin is a novel antibiotic that blocks the assembly of lipopolysaccharide (LPS) into the Pseudomonas aeruginosa outer membrane by inhibiting LPS transport protein D (LptD). Here, we demonstrated that murepavadin impairs bacterial outer membrane integrity, which induces the envelope stress response. We further found that the impaired outer membrane integrity increases the influx of β-lactam antibiotics, resulting in enhanced bactericidal effects. In addition, the combination of murepavadin and a β-lactam/β-lactamase inhibitor mixture (ceftazidime/avibactam) slowed down the resistance development of P. aeruginosa. Overall, this study demonstrates the bacterial response to murepavadin and provides a new combination strategy for effective treatment.
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Affiliation(s)
- Xiaoya Wei
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jiacong Gao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Congjuan Xu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Iain L. Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
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Wiesmann CL, Zhang Y, Alford M, Hamilton CD, Dosanjh M, Thoms D, Dostert M, Wilson A, Pletzer D, Hancock REW, Haney CH. The ColR/S two-component system is a conserved determinant of host association across Pseudomonas species. ISME J 2023; 17:286-296. [PMID: 36424517 PMCID: PMC9859794 DOI: 10.1038/s41396-022-01343-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/27/2022]
Abstract
Members of the bacterial genus Pseudomonas form mutualistic, commensal, and pathogenic associations with diverse hosts. The prevalence of host association across the genus suggests that symbiosis may be a conserved ancestral trait and that distinct symbiotic lifestyles may be more recently evolved. Here we show that the ColR/S two-component system, part of the Pseudomonas core genome, is functionally conserved between Pseudomonas aeruginosa and Pseudomonas fluorescens. Using plant rhizosphere colonization and virulence in a murine abscess model, we show that colR is required for commensalism with plants and virulence in animals. Comparative transcriptomics revealed that the ColR regulon has diverged between P. aeruginosa and P. fluorescens and deleting components of the ColR regulon revealed strain-specific, but not host-specific, requirements for ColR-dependent genes. Collectively, our results suggest that ColR/S allows Pseudomonas to sense and respond to a host, but that the ColR-regulon has diverged between Pseudomonas strains with distinct lifestyles. This suggests that conservation of two-component systems, coupled with life-style dependent diversification of the regulon, may play a role in host association and lifestyle transitions.
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Affiliation(s)
- Christina L Wiesmann
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Yue Zhang
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Morgan Alford
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Corri D Hamilton
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Manisha Dosanjh
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - David Thoms
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Melanie Dostert
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Andrew Wilson
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Daniel Pletzer
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Microbiology and Immunology, University of Otago, 720 Cumberland St., 9054, Dunedin, New Zealand
| | - Robert E W Hancock
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Cara H Haney
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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8
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Belanger CR, Dostert M, Blimkie TM, Lee AHY, Dhillon BK, Wu BC, Akhoundsadegh N, Rahanjam N, Castillo-Arnemann J, Falsafi R, Pletzer D, Haney CH, Hancock REW. Surviving the host: Microbial metabolic genes required for growth of Pseudomonas aeruginosa in physiologically-relevant conditions. Front Microbiol 2022; 13:1055512. [PMID: 36504765 PMCID: PMC9732424 DOI: 10.3389/fmicb.2022.1055512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/31/2022] [Indexed: 11/27/2022] Open
Abstract
Pseudomonas aeruginosa, like other pathogens, adapts to the limiting nutritional environment of the host by altering patterns of gene expression and utilizing alternative pathways required for survival. Understanding the genes essential for survival in the host gives insight into pathways that this organism requires during infection and has the potential to identify better ways to treat infections. Here, we used a saturated transposon insertion mutant pool of P. aeruginosa strain PAO1 and transposon insertion sequencing (Tn-Seq), to identify genes conditionally important for survival under conditions mimicking the environment of a nosocomial infection. Conditions tested included tissue culture medium with and without human serum, a murine abscess model, and a human skin organoid model. Genes known to be upregulated during infections, as well as those involved in nucleotide metabolism, and cobalamin (vitamin B12) biosynthesis, etc., were required for survival in vivo- and in host mimicking conditions, but not in nutrient rich lab medium, Mueller Hinton broth (MHB). Correspondingly, mutants in genes encoding proteins of nucleotide and cobalamin metabolism pathways were shown to have growth defects under physiologically-relevant media conditions, in vivo, and in vivo-like models, and were downregulated in expression under these conditions, when compared to MHB. This study provides evidence for the relevance of studying P. aeruginosa fitness in physiologically-relevant host mimicking conditions and identified metabolic pathways that represent potential novel targets for alternative therapies.
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Affiliation(s)
- Corrie R. Belanger
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Melanie Dostert
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Travis M. Blimkie
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Amy Huei-Yi Lee
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada,Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Bhavjinder Kaur Dhillon
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Bing Catherine Wu
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Noushin Akhoundsadegh
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Negin Rahanjam
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Javier Castillo-Arnemann
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Reza Falsafi
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada,Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cara H. Haney
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada,*Correspondence: Robert E. W. Hancock,
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9
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Raj Adhikari B, Sinha S, Lyons N, Pletzer D, Lamont I, Gordon KC, Das SC. Inhalable ceftazidime-roflumilast powder targeting infection and inflammation: Influence of incorporating roflumilast into ceftazidime-leucine co-amorphous formulation. Eur J Pharm Biopharm 2022; 180:260-268. [DOI: 10.1016/j.ejpb.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/21/2022] [Accepted: 10/07/2022] [Indexed: 11/26/2022]
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10
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V F Esposito T, Rodríguez-Rodríguez C, Blackadar C, Haney EF, Pletzer D, E W Hancock R, Saatchi K, Häfeli UO. Biodistribution and Toxicity of Innate Defense Regulator 1018 (IDR-1018). Eur J Pharm Biopharm 2022; 179:11-25. [PMID: 36028151 DOI: 10.1016/j.ejpb.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 08/03/2022] [Accepted: 08/10/2022] [Indexed: 11/04/2022]
Abstract
Innate defense regulators (IDRs) are synthetic host-defense peptides (HDPs) with broad-spectrum anti-infective properties, including immunomodulatory, anti-biofilm and direct antimicrobial activities. A lack of pharmacokinetic data about these peptides hinders their development and makes it challenging to fully understand how they work in vivo since their mechanism of action is dependent on tissue concentrations of the peptide. Here, we set out to define in detail the pharmacokinetics of a well-characterized IDR molecule, IDR-1018. To make the peptide traceable, it was radiolabeled with the long-lived gamma-emitting isotope gallium-67. After a series of bench-top characterizations, the radiotracer was administered to healthy mice intravenously (IV) or subcutaneously (SQ) at various dose levels (2.5-13 mg/kg). Nuclear imaging and ex-vivo biodistributions were used to quantify organ and tissue uptake of the radiotracer over time. When administered as an IV bolus, the distribution profile of the radiotracer changed as the dose was escalated. At 2.5 mg/kg, the peptide was well-tolerated, poorly circulated in the blood and was cleared predominately by the reticuloendothelial system. Higher doses (7 and 13 mg/kg) as an IV bolus were almost immediately lethal due to respiratory arrest; significant lung uptake of the radiotracer was observed from nuclear scans of these animals, and histological examination found extensive damage to the pulmonary vasculature and alveoli. When administered SQ at a dose of 3 mg/kg, radiolabeled IDR-1018 was rapidly absorbed from the site of injection and predominately cleared renally. Apart from the SQ injection site, no other tissue had a concentration above the minimum inhibitory concentration that would enable this peptide to exert direct antimicrobial effects against most pathogenic bacteria. Tissue concentrations were sufficient however to disrupt microbial biofilms and alter the host immune response. Overall, this study demonstrated that the administration of synthetic IDR peptide in vivo is best suited to local administration which avoids some of the issues associated with peptide toxicity that are observed when administered systemically by IV injection, an issue that will have to be addressed through formulation.
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Affiliation(s)
- Tullio V F Esposito
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada; Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Cristina Rodríguez-Rodríguez
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada; Department of Physics and Astronomy, Faculty of Science, University of British Columbia, Vancouver, Canada
| | - Colin Blackadar
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Evan F Haney
- Centre for Microbial Disease and Immunity Research, Department of Microbiology and Immunology, Faculty of Science, University of British Columbia, Vancouver, Canada; Asep Medical Holdings, Victoria, BC, Canada
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
| | - Robert E W Hancock
- Centre for Microbial Disease and Immunity Research, Department of Microbiology and Immunology, Faculty of Science, University of British Columbia, Vancouver, Canada
| | - Katayoun Saatchi
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Urs O Häfeli
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada; Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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11
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Wolfmeier H, Wardell SJT, Liu LT, Falsafi R, Draeger A, Babiychuk EB, Pletzer D, Hancock REW. Targeting the Pseudomonas aeruginosa Virulence Factor Phospholipase C With Engineered Liposomes. Front Microbiol 2022; 13:867449. [PMID: 35369481 PMCID: PMC8971843 DOI: 10.3389/fmicb.2022.867449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Engineered liposomes composed of the naturally occurring lipids sphingomyelin (Sm) and cholesterol (Ch) have been demonstrated to efficiently neutralize toxins secreted by Gram-positive bacteria such as Streptococcus pneumoniae and Staphylococcus aureus. Here, we hypothesized that liposomes are capable of neutralizing cytolytic virulence factors secreted by the Gram-negative pathogen Pseudomonas aeruginosa. We used the highly virulent cystic fibrosis P. aeruginosa Liverpool Epidemic Strain LESB58 and showed that sphingomyelin (Sm) and a combination of sphingomyelin with cholesterol (Ch:Sm; 66 mol/% Ch and 34 mol/% Sm) liposomes reduced lysis of human bronchial and red blood cells upon challenge with the Pseudomonas secretome. Mass spectrometry of liposome-sequestered Pseudomonas proteins identified the virulence-promoting hemolytic phospholipase C (PlcH) as having been neutralized. Pseudomonas aeruginosa supernatants incubated with liposomes demonstrated reduced PlcH activity as assessed by the p-nitrophenylphosphorylcholine (NPPC) assay. Testing the in vivo efficacy of the liposomes in a murine cutaneous abscess model revealed that Sm and Ch:Sm, as single dose treatments, attenuated abscesses by >30%, demonstrating a similar effect to that of a mutant lacking plcH in this infection model. Thus, sphingomyelin-containing liposome therapy offers an interesting approach to treat and reduce virulence of complex infections caused by P. aeruginosa and potentially other Gram-negative pathogens expressing PlcH.
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Affiliation(s)
- Heidi Wolfmeier
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Salzburg, Austria
| | - Samuel J. T. Wardell
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Leo T. Liu
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Reza Falsafi
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | | | | | - Daniel Pletzer
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- *Correspondence: Daniel Pletzer,
| | - Robert E. W. Hancock
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- Robert E. W. Hancock,
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12
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Nielsen JE, Alford MA, Yung DBY, Molchanova N, Fortkort JA, Lin JS, Diamond G, Hancock REW, Jenssen H, Pletzer D, Lund R, Barron AE. Self-Assembly of Antimicrobial Peptoids Impacts Their Biological Effects on ESKAPE Bacterial Pathogens. ACS Infect Dis 2022; 8:533-545. [PMID: 35175731 DOI: 10.1021/acsinfecdis.1c00536] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Antimicrobial peptides (AMPs) are promising pharmaceutical candidates for the prevention and treatment of infections caused by multidrug-resistant ESKAPE pathogens, which are responsible for the majority of hospital-acquired infections. Clinical translation of AMPs has been limited, in part by apparent toxicity on systemic dosing and by instability arising from susceptibility to proteolysis. Peptoids (sequence-specific oligo-N-substituted glycines) resist proteolytic digestion and thus are of value as AMP mimics. Only a few natural AMPs such as LL-37 and polymyxin self-assemble in solution; whether antimicrobial peptoids mimic these properties has been unknown. Here, we examine the antibacterial efficacy and dynamic self-assembly in aqueous media of eight peptoid mimics of cationic AMPs designed to self-assemble and two nonassembling controls. These amphipathic peptoids self-assembled in different ways, as determined by small-angle X-ray scattering; some adopt helical bundles, while others form core-shell ellipsoidal or worm-like micelles. Interestingly, many of these peptoid assemblies show promising antibacterial, antibiofilm activity in vitro in media, under host-mimicking conditions and antiabscess activity in vivo. While self-assembly correlated overall with antibacterial efficacy, this correlation was imperfect. Certain self-assembled morphologies seem better-suited for antibacterial activity. In particular, a peptoid exhibiting a high fraction of long, worm-like micelles showed reduced antibacterial, antibiofilm, and antiabscess activity against ESKAPE pathogens compared with peptoids that form ellipsoidal or bundled assemblies. This is the first report of self-assembling peptoid antibacterials with activity against in vivo biofilm-like infections relevant to clinical medicine.
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Affiliation(s)
- Josefine Eilsø Nielsen
- Department of Bioengineering, School of Medicine, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, University of Oslo, Oslo 0315, Norway
| | - Morgan Ashley Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Deborah Bow Yue Yung
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Natalia Molchanova
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - John A. Fortkort
- Department of Bioengineering, School of Medicine, Stanford University, Stanford, California 94305, United States
| | - Jennifer S. Lin
- Department of Bioengineering, School of Medicine, Stanford University, Stanford, California 94305, United States
| | - Gill Diamond
- Department of Oral Immunology and Infectious Diseases, University of Louisville, School of Dentistry, Louisville, Kentucky 40202, United States
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Håvard Jenssen
- Department of Science and Environment, Roskilde University, Roskilde 4000, Denmark
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Reidar Lund
- Department of Chemistry, University of Oslo, Oslo 0315, Norway
| | - Annelise E. Barron
- Department of Bioengineering, School of Medicine, Stanford University, Stanford, California 94305, United States
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13
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Harfoot R, Yung DBY, Anderson WA, Wild CEK, Coetzee N, Hernández LC, Lawley B, Pletzer D, Derraik JGB, Anderson YC, Quiñones-Mateu ME. Ultraviolet-C Irradiation, Heat, and Storage as Potential Methods of Inactivating SARS-CoV-2 and Bacterial Pathogens on Filtering Facepiece Respirators. Pathogens 2022; 11:83. [PMID: 35056031 PMCID: PMC8780977 DOI: 10.3390/pathogens11010083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/06/2022] [Accepted: 01/08/2022] [Indexed: 02/01/2023] Open
Abstract
The arrival of SARS-CoV-2 to Aotearoa/New Zealand in February 2020 triggered a massive response at multiple levels. Procurement and sustainability of medical supplies to hospitals and clinics during the then upcoming COVID-19 pandemic was one of the top priorities. Continuing access to new personal protective equipment (PPE) was not guaranteed; thus, disinfecting and reusing PPE was considered as a potential alternative. Here, we describe part of a local program intended to test and implement a system to disinfect PPE for potential reuse in New Zealand. We used filtering facepiece respirator (FFR) coupons inoculated with SARS-CoV-2 or clinically relevant multidrug-resistant pathogens (Acinetobacter baumannii Ab5075, methicillin-resistant Staphylococcus aureus USA300 LAC and cystic-fibrosis isolate Pseudomonas aeruginosa LESB58), to evaluate the potential use of ultraviolet-C germicidal irradiation (UV-C) or dry heat treatment to disinfect PPE. An applied UV-C dose of 1000 mJ/cm2 was sufficient to completely inactivate high doses of SARS-CoV-2; however, irregularities in the FFR coupons hindered the efficacy of UV-C to fully inactivate the virus, even at higher UV-C doses (2000 mJ/cm2). Conversely, incubating contaminated FFR coupons at 65 °C for 30 min or 70 °C for 15 min, was sufficient to block SARS-CoV-2 replication, even in the presence of mucin or a soil load (mimicking salivary or respiratory secretions, respectively). Dry heat (90 min at 75 °C to 80 °C) effectively killed 106 planktonic bacteria; however, even extending the incubation time up to two hours at 80 °C did not completely kill bacteria when grown in colony biofilms. Importantly, we also showed that FFR material can harbor replication-competent SARS-CoV-2 for up to 35 days at room temperature in the presence of a soil load. We are currently using these findings to optimize and establish a robust process for decontaminating, reusing, and reducing wastage of PPE in New Zealand.
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Affiliation(s)
- Rhodri Harfoot
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (R.H.); (D.B.Y.Y.); (L.C.H.); (B.L.); (D.P.)
| | - Deborah B. Y. Yung
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (R.H.); (D.B.Y.Y.); (L.C.H.); (B.L.); (D.P.)
| | - William A. Anderson
- Department of Chemical Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
| | - Cervantée E. K. Wild
- Department of Paediatrics, Child and Youth Health, University of Auckland, Auckland 1010, New Zealand; (C.E.K.W.); (N.C.); (J.G.B.D.)
| | - Nicolene Coetzee
- Department of Paediatrics, Child and Youth Health, University of Auckland, Auckland 1010, New Zealand; (C.E.K.W.); (N.C.); (J.G.B.D.)
| | - Leonor C. Hernández
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (R.H.); (D.B.Y.Y.); (L.C.H.); (B.L.); (D.P.)
| | - Blair Lawley
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (R.H.); (D.B.Y.Y.); (L.C.H.); (B.L.); (D.P.)
| | - Daniel Pletzer
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (R.H.); (D.B.Y.Y.); (L.C.H.); (B.L.); (D.P.)
| | - José G. B. Derraik
- Department of Paediatrics, Child and Youth Health, University of Auckland, Auckland 1010, New Zealand; (C.E.K.W.); (N.C.); (J.G.B.D.)
| | - Yvonne C. Anderson
- Department of Paediatrics, Child and Youth Health, University of Auckland, Auckland 1010, New Zealand; (C.E.K.W.); (N.C.); (J.G.B.D.)
| | - Miguel E. Quiñones-Mateu
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (R.H.); (D.B.Y.Y.); (L.C.H.); (B.L.); (D.P.)
- Webster Centre for Infectious Diseases, University of Otago, Dunedin 9016, New Zealand
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14
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Drayton M, Alford MA, Pletzer D, Haney EF, Machado Y, Luo HD, Overall CM, Kizhakkedathu JN, Hancock REW, Straus SK. Enzymatically releasable polyethylene glycol - host defense peptide conjugates with improved activity and biocompatibility. J Control Release 2021; 339:220-231. [PMID: 34597746 DOI: 10.1016/j.jconrel.2021.09.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/13/2021] [Accepted: 09/26/2021] [Indexed: 10/20/2022]
Abstract
Host defense peptides (HDPs) have been the subject of great interest for the treatment of multidrug-resistant bacterial infections due to their multimodal activity and low induction of resistance. However, aggregation, toxicity, and short biological half-life have limited their applicability for clinical treatment. Many methods have been explored to alleviate these issues, such as polymer (e.g., polyethylene glycol (PEG)) conjugation, but these are often accompanied by reductions in the activity of the HDP. Here, we detail the design of a novel PEG-HDP conjugate incorporating an enzymatic cleavage sequence targeting matrix metalloproteinases (MMPs) that accumulate at sites of inflammation and infection. Addition of the cleavage sequence onto either the N- or the C-terminal region of the parent peptide (peptide 73, a derivative of the HDP aurein 2.2) was explored to determine the location for optimal antimicrobial activity following MMP cleavage; furthermore, the susceptibility of the peptide to MMP cleavage after conjugation to 2 kDa or 5 kDa PEG was examined. The top candidate, L73, utilized an N-terminal cleavage site that was subsequently conjugated to a 2 kDa PEG polymer. Both L73 and the conjugate exhibited no antimicrobial activity in vitro until cleaved by purified MMP, which liberated a peptide fragment with 16- or 63-fold improved activity, respectively, corresponding to a minimum inhibitory concentration (MIC) of 8 μg/mL, comparable to that of peptide 73 (4 μg/mL). Furthermore, PEG conjugation improved the blood compatibility and reduced the aggregation tendency of the HDP in vitro, indicating enhanced biocompatibility. When administered as a single subcutaneous dose (~3.6 mg, or a peptide concentration of 142 mg/kg) in a mouse abscess model of high-density methicillin-resistant Staphylococcus aureus (MRSA) infection, the conjugate displayed strong activity, reducing abscess size and bacterial load by 73.3% and 58-fold, respectively. This activity was completely lost when the cleavage site was rendered resistant to MMPs by the substitution of two d-amino acids, supporting the hypothesis that antimicrobial activity was dependent on cleavage by MMPs, which were shown here to increasingly accumulate at the abscess site up to 18 h post infection. Finally, the conjugate displayed biocompatibility in vivo, with no identifiable toxicity or aggregation.
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Affiliation(s)
- Matthew Drayton
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Centre for Blood Research, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Morgan A Alford
- Centre for Blood Research, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada; Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, BC V6T 1Z4, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, BC V6T 1Z4, Canada; Department of Microbiology and Immunology, University of Otago, 720 Cumberland St, Dunedin, New Zealand
| | - Evan F Haney
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, BC V6T 1Z4, Canada
| | - Yoan Machado
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Haiming D Luo
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Centre for Blood Research, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Christopher M Overall
- Centre for Blood Research, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada; Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Jayachandran N Kizhakkedathu
- Centre for Blood Research, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, 2350 Health Sciences Mall, Vancouver V6T 1Z3, Canada; The School of Biomedical Engineering, University of British Columbia, 2222 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, BC V6T 1Z4, Canada
| | - Suzana K Straus
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
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15
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Ren H, Zhang J, Zhou J, Xu C, Fan Z, Pan X, Li S, Liang Y, Chen S, Xu J, Wang P, Zhang Y, Zhu G, Liu H, Jin Y, Bai F, Cheng Z, Pletzer D, Wu W. Synergistic bactericidal activities of tobramycin with ciprofloxacin and azithromycin against Klebsiella pneumoniae. J Antibiot (Tokyo) 2021; 74:528-537. [PMID: 34050325 DOI: 10.1038/s41429-021-00427-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/09/2022]
Abstract
Trans-translation is a unique bacterial ribosome rescue system that plays important roles in the tolerance to environmental stresses. It is composed of an ssrA-encoded tmRNA and a protein SmpB. In this study, we examined the role of trans-translation in antibiotic tolerance in Klebsiella pneumoniae and explored whether the inhibition of this mechanism could enhance the bactericidal activities of antibiotics. We found that deletion of the ssrA gene reduced the survival of K. pneumoniae after treatment with kanamycin, tobramycin, azithromycin, and ciprofloxacin, indicating an important role of the trans-translation in bacterial antibiotic tolerance. By using a modified ssrA gene with a 6×His tag we demonstrated that tobramycin suppressed the azithromycin and ciprofloxacin-elicited activation of trans-translation. The results were further confirmed with a trans-translation reporter system that is composed of a normal mCherry gene and a gfp gene without the stop codon. Compared to each individual antibiotic, combination of tobramycin with azithromycin or ciprofloxacin synergistically enhanced the killing activities against planktonic K. pneumoniae cells and improved bacterial clearance in a murine cutaneous abscess infection model. In addition, the combination of tobramycin and ciprofloxacin increased the bactericidal activities against biofilm-associated cells. Overall, our results suggest that the combination of tobramycin with azithromycin or ciprofloxacin is a promising strategy in combating K. pneumoniae infections.
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Affiliation(s)
- Huan Ren
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jingyi Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jingyi Zhou
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Congjuan Xu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Zheng Fan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Shouyi Li
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Yuying Liang
- Department of laboratory medicine, 5th medical center of PLA general hospital, Beijing, 100071, China
| | - Shuiping Chen
- Department of laboratory medicine, 5th medical center of PLA general hospital, Beijing, 100071, China
| | - Jun Xu
- NHC Key Laboratory of Hormones and Development (Tianjin Medical University), Tianjin Key Laboratory of Metabolic Diseases, Diabetic foot Department, Tianjin Medical University Metabolic Disease Hospital & Chu Hsien-I Memorial Hospital, Tianjin, 300070, China
| | - Penghua Wang
- NHC Key Laboratory of Hormones and Development (Tianjin Medical University), Tianjin Key Laboratory of Metabolic Diseases, Diabetic foot Department, Tianjin Medical University Metabolic Disease Hospital & Chu Hsien-I Memorial Hospital, Tianjin, 300070, China
| | - Yanhong Zhang
- Nankai University Affiliated Hospital (Tianjin Forth Hospital), Tianjin, 300222, China
| | - Guangbo Zhu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, 300121, China
| | - Huimin Liu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, 300121, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Daniel Pletzer
- Department of Microbiology & Immunology, University of Otago, Dunedin, 9054, New Zealand
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
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16
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Wilkinson LV, Alford MA, Coleman SR, Wu BC, Lee AHY, Blimkie TM, Bains M, Falsafi R, Pletzer D, Hancock REW. Peptide 1018 inhibits swarming and influences Anr-regulated gene expression downstream of the stringent stress response in Pseudomonas aeruginosa. PLoS One 2021; 16:e0250977. [PMID: 33930077 PMCID: PMC8087004 DOI: 10.1371/journal.pone.0250977] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/16/2021] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen that causes considerable human morbidity and mortality, particularly in nosocomial infections and individuals with cystic fibrosis. P. aeruginosa can adapt to surface growth by undergoing swarming motility, a rapid multicellular movement that occurs on viscous soft surfaces with amino acids as a nitrogen source. Here we tested the small synthetic host defense peptide, innate defense regulator 1018, and found that it inhibited swarming motility at concentrations as low as 0.75 μg/ml, well below the MIC for strain PA14 planktonic cells (64 μg/ml). A screen of the PA14 transposon insertion mutant library revealed 29 mutants that were more tolerant to peptide 1018 during swarming, five of which demonstrated significantly greater swarming than the WT in the presence of peptide. Transcriptional analysis (RNA-Seq) of cells that were inoculated on swarming plates containing 1.0 μg/ml peptide revealed differential expression of 1,190 genes compared to cells swarming on plates without peptide. Furthermore, 1018 treatment distinctly altered the gene expression profile of cells when compared to that untreated cells in the centre of the swarm colonies. Peptide-treated cells exhibited changes in the expression of genes implicated in the stringent stress response including those regulated by anr, which is involved in anaerobic adaptation, indicative of a mechanism by which 1018 might inhibit swarming motility. Overall, this study illustrates potential mechanisms by which peptide 1018 inhibits swarming surface motility, an important bacterial adaptation associated with antibiotic resistance, virulence, and dissemination of P. aeruginosa.
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Affiliation(s)
- Lauren V. Wilkinson
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Morgan A. Alford
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Shannon R. Coleman
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Bing C. Wu
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Amy H. Y. Lee
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
| | - Travis M. Blimkie
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Manjeet Bains
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Reza Falsafi
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- * E-mail:
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17
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Alford MA, Choi KYG, Trimble MJ, Masoudi H, Kalsi P, Pletzer D, Hancock REW. Murine Model of Sinusitis Infection for Screening Antimicrobial and Immunomodulatory Therapies. Front Cell Infect Microbiol 2021; 11:621081. [PMID: 33777834 PMCID: PMC7994591 DOI: 10.3389/fcimb.2021.621081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 01/22/2021] [Indexed: 12/24/2022] Open
Abstract
The very common condition of sinusitis is characterized by persistent inflammation of the nasal cavity, which contributes to chronic rhinosinusitis and morbidity of cystic fibrosis patients. Colonization by opportunistic pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa triggers inflammation that is exacerbated by defects in the innate immune response. Pathophysiological mechanisms underlying initial colonization of the sinuses are not well established. Despite their extensive use, current murine models of acute bacterial rhinosinusitis have not improved the understanding of early disease stages due to analytical limitations. In this study, a model is described that is technically simple, allows non-invasive tracking of bacterial infection, and screening of host-responses to infection and therapies. The model was modified to investigate longer-term infection and disease progression by using a less virulent, epidemic P. aeruginosa cystic fibrosis clinical isolate LESB65. Tracking of luminescent bacteria was possible after intranasal infections, which were sustained for up to 120 h post-infection, without compromising the overall welfare of the host. Production of reactive oxidative species was associated with neutrophil localization to the site of infection in this model. Further, host-defense peptides administered by Respimat® inhaler or intranasal instillation reduced bacterial burden and impacted disease progression as well as cytokine responses associated with rhinosinusitis. Thus, future studies using this model will improve our understanding of rhinosinusitis etiology and early stage pathogenesis, and can be used to screen for the efficacy of emerging therapies pre-clinically.
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Affiliation(s)
- Morgan A. Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Ka-Yee G. Choi
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Michael J. Trimble
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- British Columbia Centre for Disease Control, Public Health Services Authority, Vancouver, BC, Canada
| | - Hamid Masoudi
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Pavneet Kalsi
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
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18
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Yung DBY, Sircombe KJ, Pletzer D. Friends or enemies? The complicated relationship between Pseudomonas aeruginosa and Staphylococcus aureus. Mol Microbiol 2021; 116:1-15. [PMID: 33576132 DOI: 10.1111/mmi.14699] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 10/22/2022]
Abstract
Pseudomonas aeruginosa (Pa) and Staphylococcus aureus (Sa) are opportunistic pathogens that are most commonly co-isolated from chronic wounds and the sputum of cystic fibrosis patients. Over the last few years, there have been plenty of contrasting results from studies involving P. aeruginosa and S. aureus co-cultures. The general concept that P. aeruginosa outcompetes S. aureus has been challenged and there is more evidence now that they can co-exist. Nevertheless, it still remains difficult to mimic polymicrobial infections in vitro and in vivo. In this review, we discuss recent advances in regard to Pa-Sa molecular interactions, their physical responses, and in vitro and in vivo models. We believe it is important to optimize growth conditions in the laboratory, determine appropriate bacterial starting ratios, and consider environmental factors to study the co-existence of these two pathogens. Ideally, optimized growth media should reflect host-mimicking conditions with or without host cells that allow both bacteria to co-exist. To further identify mechanisms that could help to treat these complex infections, we propose to use relevant polymicrobial animal models. Ultimately, we briefly discuss how polymicrobial infections can increase antibiotic tolerance.
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Affiliation(s)
- Deborah Bow Yue Yung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | | | - Daniel Pletzer
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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19
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Pletzer D, Asnis J, Slavin YN, Hancock REW, Bach H, Saatchi K, Häfeli UO. Rapid microwave-based method for the preparation of antimicrobial lignin-capped silver nanoparticles active against multidrug-resistant bacteria. Int J Pharm 2021; 596:120299. [PMID: 33524525 DOI: 10.1016/j.ijpharm.2021.120299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/17/2022]
Abstract
Due to the increasing inability of antibiotics to treat multidrug-resistant (MDR) bacteria, metal and metal oxide nanoparticles have been gaining interest as antimicrobial agents. Among those, silver nanoparticles have been used extensively as broad-spectrum antimicrobial agents. Here, we describe a newly-developed, 10-min (120 °C at 5 bar pressure) microwave-assisted synthesis of silver nanoparticles made from the wood biopolymer lignin as a reducing and capping agent. The resulting lignin-capped silver nanoparticles (AgLNPs) had an average particle diameter of 13.4 ± 2.8 nm. Antimicrobial susceptibility assays against a variety of MDR clinical Gram-positive and Gram-negative pathogens revealed a minimal inhibitory concentration (MIC) of AgLNPs ≤5 µg/mL. AgLNPs (10 µg/mL) showed ≤20% cytotoxicity towards monocytic THP-1 cells and were well tolerated when administered subcutaneously in mice at high concentrations (5 mg at a concentration of 100 mg/mL) with no obvious toxicity. AgLNPs showed efficacy in an in vivo infection (abscess) mouse model against MDR Pseudomonas aeruginosa LESB58 and methicillin-resistant Staphylococcus aureus USA300. A significant decrease in abscess sizes was observed for both strains as well as a reduction in bacterial loads of P. aeruginosa after three days. This demonstrates that microwave-assisted synthesis provides an optimized strategy for the production of AgLNPs while maintaining antimicrobial activity in vitro and in vivo.
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Affiliation(s)
- Daniel Pletzer
- Centre for Microbial Disease and Immunity Research, Department of Microbiology and Immunology, Faculty of Science, University of British Columbia, Vancouver, Canada; Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Jason Asnis
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Yael N Slavin
- Faculty of Medicine, Division of Infectious Diseases, University of British Columbia, Vancouver, BC, Canada
| | - Robert E W Hancock
- Centre for Microbial Disease and Immunity Research, Department of Microbiology and Immunology, Faculty of Science, University of British Columbia, Vancouver, Canada
| | - Horacio Bach
- Faculty of Medicine, Division of Infectious Diseases, University of British Columbia, Vancouver, BC, Canada.
| | - Katayoun Saatchi
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.
| | - Urs O Häfeli
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.
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20
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Wu BC, Haney EF, Akhoundsadegh N, Pletzer D, Trimble MJ, Adriaans AE, Nibbering PH, Hancock REW. Human organoid biofilm model for assessing antibiofilm activity of novel agents. NPJ Biofilms Microbiomes 2021; 7:8. [PMID: 33495449 PMCID: PMC7835231 DOI: 10.1038/s41522-020-00182-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 12/11/2020] [Indexed: 02/08/2023] Open
Abstract
Bacterial biofilms cause 65% of all human infections and are highly resistant to antibiotic therapy but lack specific treatments. To provide a human organoid model for studying host-microbe interplay and enabling screening for novel antibiofilm agents, a human epidermis organoid model with robust methicillin-resistant Staphylococcus aureus (MRSA) USA300 and Pseudomonas aeruginosa PAO1 biofilm was developed. Treatment of 1-day and 3-day MRSA and PAO1 biofilms with antibiofilm peptide DJK-5 significantly and substantially reduced the bacterial burden. This model enabled the screening of synthetic host defense peptides, revealing their superior antibiofilm activity against MRSA compared to the antibiotic mupirocin. The model was extended to evaluate thermally wounded skin infected with MRSA biofilms resulting in increased bacterial load, cytotoxicity, and pro-inflammatory cytokine levels that were all reduced upon treatment with DJK-5. Combination treatment of DJK-5 with an anti-inflammatory peptide, 1002, further reduced cytotoxicity and skin inflammation.
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Affiliation(s)
- Bing Catherine Wu
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Evan F Haney
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Noushin Akhoundsadegh
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand
| | - Michael J Trimble
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Alwin E Adriaans
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter H Nibbering
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert E W Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada.
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21
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Coleman SR, Pletzer D, Hancock REW. Contribution of Swarming Motility to Dissemination in a Pseudomonas aeruginosa Murine Skin Abscess Infection Model. J Infect Dis 2020; 224:726-733. [PMID: 33349847 DOI: 10.1093/infdis/jiaa778] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 12/16/2020] [Indexed: 01/21/2023] Open
Abstract
Swarming motility in Pseudomonas aeruginosa is a multicellular adaptation induced by semisolid medium with amino acids as a nitrogen source. By phenotypic screening, we differentiated swarming from other complex adaptive phenotypes, such as biofilm formation, swimming and twitching, by identifying a swarming-specific mutant in ptsP, a metabolic regulator. This swarming-deficient mutant was tested in an acute murine skin abscess infection model. Bacteria were recovered at significantly lower numbers from organs of mice infected with the ∆ptsP mutant. We also tested the synthetic peptide 1018 for activity against different motilities and efficacy in vivo. Treatment with peptide 1018 mimicked the phenotype of the ∆ptsP mutant in vitro, as swarming was inhibited at low concentrations (<2 μg/mL) but not swimming or twitching, and in vivo, as mice had a reduced bacterial load recovered from organs. Therefore, PtsP functions as a regulator of swarming, which in turn contributes to dissemination and colonization in vivo.
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Affiliation(s)
- Shannon R Coleman
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.,Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
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22
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Etayash H, Qian Y, Pletzer D, Zhang Q, Xie J, Cui R, Dai C, Ma P, Qi F, Liu R, Hancock REW. Host Defense Peptide-Mimicking Amphiphilic β-Peptide Polymer (Bu:DM) Exhibiting Anti-Biofilm, Immunomodulatory, and in Vivo Anti-Infective Activity. J Med Chem 2020; 63:12921-12928. [PMID: 33126797 DOI: 10.1021/acs.jmedchem.0c01321] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Therapeutic options to treat multidrug resistant bacteria, especially when present in biofilms, are limited due to their high levels of antibiotic resistance. Here, we report the anti-biofilm and immunomodulatory activities of the host defense peptide (HDP)-mimicking β-peptide polymer (20:80 Bu:DM) and investigated its activity in vivo. The polymer outperformed antibiotics in the removal and reduction of the viability of established biofilms, achieving a maximum activity of around 80% reduction in viability. Interestingly the polymer also exhibited HDP-like immunomodulation in inducing chemokines and anti-inflammatory cytokines and suppressing lipopolysaccharide-induced proinflammatory cytokines. When tested in a murine, high-density skin infection model using P. aeruginosa LESB58, the polymer was effective in diminishing abscess size and reducing bacterial load. This study demonstrates the dual functionality of HDP-mimicking β-peptide polymers in inhibiting biofilms and modulating innate immunity, as well as reducing tissue dermonecrosis.
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Affiliation(s)
- Hashem Etayash
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia V6T 1Z4, Canada
| | - Yuxin Qian
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia V6T 1Z4, Canada.,Department of Microbiology and Immunology, University of Otago, 720 Cumberland Street, Dunedin 9054, New Zealand
| | - Qiang Zhang
- Key Laboratory for Ultrafine Materials of Ministry of Education, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jiayang Xie
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ruxin Cui
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Chengzhi Dai
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Pengcheng Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Fan Qi
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Runhui Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.,Key Laboratory for Ultrafine Materials of Ministry of Education, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia V6T 1Z4, Canada
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23
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Etayash H, Pletzer D, Kumar P, Straus SK, Hancock REW. Cyclic Derivative of Host-Defense Peptide IDR-1018 Improves Proteolytic Stability, Suppresses Inflammation, and Enhances In Vivo Activity. J Med Chem 2020; 63:9228-9236. [PMID: 32787088 DOI: 10.1021/acs.jmedchem.0c00303] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Host-defense peptides have drawn significant attention as new drugs or drug adjuvants to combat multidrug-resistant bacteria. In this study, we report the development of cyclic derivatives of the immunomodulatory and antibiofilm innate defense regulator peptide (IDR)-1018 based on three different synthetic strategies including head-to-tail cyclization (C1), side-chain-to-tail cyclization (C2), and a disulfide bond cross-linkage (C3). The generated mimetics showed enhanced proteolytic stability and reduced aggregation in vitro and in vivo. The C2 derivative exhibited exceptional ability to suppress inflammation and significantly reduce bacterial loads in a high-density Staphylococcus aureus murine skin infection model. The findings describe different routes to the creation of enzymatically stable mimetics of IDR-1018 and identify a promising new cyclic analogue against bacterial infections.
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Affiliation(s)
- Hashem Etayash
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver V6T 1Z4, British Columbia, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver V6T 1Z4, British Columbia, Canada.,Department of Microbiology and Immunology, University of Otago, 720 Cumberland Street, Dunedin 9054, New Zealand
| | - Prashant Kumar
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver V6T 1Z1, British Columbia, Canada
| | - Suzana K Straus
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver V6T 1Z1, British Columbia, Canada
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver V6T 1Z4, British Columbia, Canada
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24
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Khomtchouk KM, Kouhi A, Xia A, Bekale LA, Massa SM, Sweere JM, Pletzer D, Hancock RE, Bollyky PL, Santa Maria PL. A novel mouse model of chronic suppurative otitis media and its use in preclinical antibiotic evaluation. Sci Adv 2020; 6:eabc1828. [PMID: 32851190 PMCID: PMC7428333 DOI: 10.1126/sciadv.abc1828] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 07/02/2020] [Indexed: 05/06/2023]
Abstract
Chronic suppurative otitis media (CSOM) is a neglected pediatric disease affecting 330 million worldwide for which no new drugs have been introduced for over a decade. We developed a mouse model with utility in preclinical drug evaluation and antimicrobial discovery. Our model used immune-competent mice, tympanic membrane perforation and inoculation with luminescent Pseudomonas aeruginosa that enabled bacterial abundance tracking in real-time for 100 days. The resulting chronic infection exhibited hallmark features of clinical CSOM, including inhibition of tympanic membrane healing and purulent ear discharge. We evaluated the standard care fluoroquinolone ofloxacin and demonstrated that this therapy resulted in a temporary reduction of bacterial burden. These data are consistent with the clinical problem of persistent infection in CSOM and the need for therapeutic outcome measures that assess eradication post-therapeutic endpoint. We conclude that this novel mouse model of CSOM has value in investigating new potential therapies.
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Affiliation(s)
- Kelly M. Khomtchouk
- Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, CA, USA
| | - Ali Kouhi
- Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, CA, USA
- Department of Otolaryngology, Head and Neck Surgery, Tehran University of Medical Sciences, Tehran, Iran
| | - Anping Xia
- Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, CA, USA
| | - Laurent Adonis Bekale
- Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, CA, USA
| | - Solange M. Massa
- Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, CA, USA
| | - Jolien M. Sweere
- Department of Medicine, Infectious Diseases, Stanford University, Stanford, CA, USA
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Robert E. Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Paul L. Bollyky
- Department of Medicine, Infectious Diseases, Stanford University, Stanford, CA, USA
| | - Peter L. Santa Maria
- Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, CA, USA
- Corresponding author.
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25
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Alford MA, Baghela A, Yeung ATY, Pletzer D, Hancock REW. NtrBC Regulates Invasiveness and Virulence of Pseudomonas aeruginosa During High-Density Infection. Front Microbiol 2020; 11:773. [PMID: 32431676 PMCID: PMC7214821 DOI: 10.3389/fmicb.2020.00773] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 03/31/2020] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is a major cause of nosocomial and chronic infections contributing to morbidity and mortality in cystic fibrosis patients. One of the reasons for its success as a pathogen is its ability to adapt to a broad range of circumstances. Here, we show the involvement of the general nitrogen regulator NtrBC, which is structurally conserved but functionally diverse across species, in pathogenic and adaptive states of P. aeruginosa. The role of NtrB and NtrC was examined in progressive or chronic infections, which revealed that mutants (ΔntrB, ΔntrC, and ΔntrBC) were reduced in their ability to invade and cause damage in a high-density abscess model in vivo. Progressive infections were established with mutants in the highly virulent PA14 genetic background, whereas chronic infections were established with mutants in the less virulent clinical isolate LESB58 genetic background. Characterization of adaptive lifestyles in vitro confirmed that the double ΔntrBC mutant demonstrated >40% inhibition of biofilm formation, a nearly complete inhibition of swarming motility, and a modest decrease and altered surfing motility colony appearance; with the exception of swarming, single mutants generally had more subtle or no changes. Transcriptional profiles of deletion mutants under swarming conditions were defined using RNA-Seq and unveiled dysregulated expression of hundreds of genes implicated in virulence in PA14 and LESB58 chronic lung infections, as well as carbon and nitrogen metabolism. Thus, transcriptional profiles were validated by testing responsiveness of mutants to several key intermediates of central metabolic pathways. These results indicate that NtrBC is a global regulatory system involved in both pathological and physiological processes relevant to the success of Pseudomonas in high-density infection.
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Affiliation(s)
- Morgan A Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Arjun Baghela
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | | | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada.,Department of Microbiology, University of Otago, Dunedin, New Zealand
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada.,Wellcome Sanger Institute, Hinxton, United Kingdom
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26
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Pletzer D, Sun E, Ritchie C, Wilkinson L, Liu LT, Trimble MJ, Wolfmeier H, Blimkie TM, Hancock REW. Surfing motility is a complex adaptation dependent on the stringent stress response in Pseudomonas aeruginosa LESB58. PLoS Pathog 2020; 16:e1008444. [PMID: 32208458 PMCID: PMC7122816 DOI: 10.1371/journal.ppat.1008444] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 04/03/2020] [Accepted: 02/29/2020] [Indexed: 11/18/2022] Open
Abstract
Cystic fibrosis (CF) is a genetic disease that affects mucin-producing body organs such as the lungs. Characteristic of CF is the production of thick, viscous mucus, containing the glycoprotein mucin, that can lead to progressive airway obstruction. Recently, we demonstrated that the presence of mucin induced a rapid surface adaptation in motile bacteria termed surfing motility, which data presented here indicates is very different from swarming motility. Pseudomonas aeruginosa, the main colonizing pathogen in CF, employs several stress coping mechanisms to survive the highly viscous environment of the CF lung. We used motility-based assays and RNA-Seq to study the stringent stress response in the hypervirulent CF isolate LESB58 (Liverpool Epidemic Strain). Motility experiments revealed that an LESB58 stringent response mutant (ΔrelAΔspoT) was unable to surf. Transcriptional profiling of ΔrelAΔspoT mutant cells from surfing agar plates, when compared to wild-type cells from the surfing edge, revealed 2,584 dysregulated genes. Gene Ontology and KEGG enrichment analysis revealed effects of the stringent response on amino acid, nucleic acid and fatty acid metabolism, TCA cycle and glycolysis, type VI secretion, as well as chemotaxis, cell communication, iron transport, nitrogen metabolic processes and cyclic-di-GMP signalling. Screening of the ordered PA14 transposon library revealed 224 mutants unable to surf and very limited overlap with genes required for swarming. Mutants affecting surfing included two downstream effector genes of the stringent stress response, the copper regulator cueR and the quinolone synthase pqsH. Both the cueR and pqsH cloned genes complemented the surfing deficiency of ΔrelAΔspoT. Our study revealed insights into stringent stress dependency in LESB58 and showed that surfing motility is stringently-controlled via the expression of cueR and pqsH. Downstream factors of the stringent stress response are important to investigate in order to fully understand its ability to colonize and persist in the CF lung.
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Affiliation(s)
- Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- * E-mail: (DP); (REWH)
| | - Evelyn Sun
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Caleb Ritchie
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Lauren Wilkinson
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Leo T. Liu
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Michael J. Trimble
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Heidi Wolfmeier
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Travis M. Blimkie
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- * E-mail: (DP); (REWH)
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Kłodzińska SN, Pletzer D, Rahanjam N, Rades T, Hancock RE, Nielsen HM. Hyaluronic acid-based nanogels improve in vivo compatibility of the anti-biofilm peptide DJK-5. Nanomedicine: Nanotechnology, Biology and Medicine 2019; 20:102022. [DOI: 10.1016/j.nano.2019.102022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/18/2019] [Accepted: 05/24/2019] [Indexed: 10/26/2022]
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Abstract
In the face of rising antimicrobial resistance, there is an urgent need for the development of efficient and effective anti-infective compounds. Adaptive resistance, a reversible bacterial phenotype characterized by the ability to surmount antibiotic challenge without mutation, is triggered to cope in situ with several stressors and is very common clinically. Thus, it is important to target stress-response effectors that contribute to in vivo adaptations and associated lifestyles such as biofilm formation. Interfering with these proteins should provide a means of dismantling bacterial virulence for treating infectious diseases, in combination with conventional antibiotics.
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Affiliation(s)
- Morgan A. Alford
- Centre for Microbial Diseases and Immunity ResearchDepartment of Microbiology and ImmunologyUniversity of British ColumbiaVancouverBCCanada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity ResearchDepartment of Microbiology and ImmunologyUniversity of British ColumbiaVancouverBCCanada
| | - Robert E.W. Hancock
- Centre for Microbial Diseases and Immunity ResearchDepartment of Microbiology and ImmunologyUniversity of British ColumbiaVancouverBCCanada
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29
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Kumar P, Pletzer D, Haney EF, Rahanjam N, Cheng JTJ, Yue M, Aljehani W, Hancock REW, Kizhakkedathu JN, Straus SK. Aurein-Derived Antimicrobial Peptides Formulated with Pegylated Phospholipid Micelles to Target Methicillin-Resistant Staphylococcus aureus Skin Infections. ACS Infect Dis 2019; 5:443-453. [PMID: 30565465 DOI: 10.1021/acsinfecdis.8b00319] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antimicrobial peptides have been the focus of considerable research; however, issues associated with toxicity and aggregation have the potential to limit clinical applications. Here, a derivative of a truncated version of aurein 2.2 (aurein 2.2Δ3), namely peptide 73, was investigated, along with its d-amino acid counterpart (D-73) and a retro-inverso version (RI-73). A version that incorporated a cysteine residue to the C-terminus (73c) was also generated, as this form is required to covalently attach antimicrobial peptides to polymers (e.g., polyethylene glycol (PEG) or hyperbranched polyglycerol (HPG)). The antimicrobial activity of the 73-derived peptides was enhanced 2- to 8-fold, and all the derivatives eradicated preformed Staphylococcus aureus biofilms. Formulation of the peptides with compatible polyethylene glycol (PEG)-modified phospholipid micelles alleviated toxicity toward human cells and reduced aggregation. When evaluated in vivo, the unformulated d-enantiomers aggregated when injected under the skin of mice, but micelle encapsulated peptides were well absorbed. Pegylated micelle formulated peptides were investigated for their potential as therapeutic agents for treating high-density infections in a murine cutaneous abscess model. Formulated peptide 73 reduced abscess size by 36% and bacterial loads by 2.2-fold compared to the parent peptide aurein 2.2Δ3. Micelle encapsulated peptides 73c and D-73 exhibited superior activity, further reducing abscess sizes by 85% and 63% and lowering bacterial loads by 510- and 9-fold compared to peptide 73.
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Affiliation(s)
- Prashant Kumar
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z1
- Centre for Blood Research, Department of Pathology and Laboratory Medicine, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, British Columbia, Canada, V6T 1Z3
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia, Canada, V6T 1Z4
| | - Evan F. Haney
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia, Canada, V6T 1Z4
| | - Negin Rahanjam
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia, Canada, V6T 1Z4
| | - John T. J. Cheng
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia, Canada, V6T 1Z4
| | - Marty Yue
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z1
| | - Waleed Aljehani
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z1
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, Vancouver, British Columbia, Canada, V6T 1Z4
| | - Jayachandran N. Kizhakkedathu
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z1
- Centre for Blood Research, Department of Pathology and Laboratory Medicine, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, British Columbia, Canada, V6T 1Z3
| | - Suzana K. Straus
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z1
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Woehlk H, Trimble MJ, Mansour SC, Pletzer D, Trouillet V, Welle A, Barner L, Hancock REW, Barner-Kowollik C, Fairfull-Smith KE. Controlling biofilm formation with nitroxide functional surfaces. Polym Chem 2019. [DOI: 10.1039/c9py00690g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nitroxide functional polymer coatings with inherent antibiofilm activity are introduced as an avenue to combat bacterial biofilm contamination of medical devices.
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31
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Affiliation(s)
- Daniel Pletzer
- Department of Microbiology & Immunology, Centre for Microbial Diseases & Immunity Research, University of British Columbia, Vancouver, Canada, V6T 1Z4
| | - Robert Ew Hancock
- Department of Microbiology & Immunology, Centre for Microbial Diseases & Immunity Research, University of British Columbia, Vancouver, Canada, V6T 1Z4
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32
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Pletzer D, Mansour SC, Hancock REW. Synergy between conventional antibiotics and anti-biofilm peptides in a murine, sub-cutaneous abscess model caused by recalcitrant ESKAPE pathogens. PLoS Pathog 2018; 14:e1007084. [PMID: 29928049 PMCID: PMC6013096 DOI: 10.1371/journal.ppat.1007084] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/09/2018] [Indexed: 01/04/2023] Open
Abstract
With the antibiotic development pipeline running dry, many fear that we might soon run out of treatment options. High-density infections are particularly difficult to treat due to their adaptive multidrug-resistance and currently there are no therapies that adequately address this important issue. Here, a large-scale in vivo study was performed to enhance the activity of antibiotics to treat high-density infections caused by multidrug-resistant Gram-positive and Gram-negative bacteria. It was shown that synthetic peptides can be used in conjunction with the antibiotics ciprofloxacin, meropenem, erythromycin, gentamicin, and vancomycin to improve the treatment outcome of murine cutaneous abscesses caused by clinical hard-to-treat pathogens including all ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter cloacae) pathogens and Escherichia coli. Promisingly, combination treatment often showed synergistic effects that significantly reduced abscess sizes and/or improved clearance of bacterial isolates from the infection site, regardless of the antibiotic mode of action. In vitro data suggest that the mechanisms of peptide action in vivo include enhancement of antibiotic penetration and potential disruption of the stringent stress response. There has been enormous publicity about the inexorable rise of resistance and the dearth of new therapies. However less attention has been placed on adaptively multidrug-resistant high density bacterial infections for which antibiotics are highly used but no effective therapies currently exist. Here we have provided new hope for this previously intractable class of infections as typified by abscess infections that are responsible for 3.2 million annual emergency room visits in the US alone. We show how to enhance the activity of antibiotics to treat multidrug-resistant Gram-positive and Gram-negative bacteria, using peptides that target the bacterial stress response, persister-based resistance and the outer membrane permeability barrier. In particular we have employed a new bacterial subcutaneous abscess mouse model to demonstrate that: (a) 7 of the society’s most recalcitrant pathogens formed cutaneous abscesses and even when antibiotics were directly delivered into abscess tissues, they showed poor efficacy; (b) By combining antibiotics with the local administration of anti-biofilm peptides that target cellular (stringent) stress responses, we could pharmacologically treat the infection and reduce the severity of cutaneous abscesses; (c) This synergy was due to increased outer membrane permeability as well as the disruption of the conserved stringent stress response that controls virulence and antibiotic resistance, particularly due to so-called persisters. These peptides have therefore the potential to broaden our limited antibiotic arsenal for a group of extremely difficult to treat infections.
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Affiliation(s)
- Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Sarah C. Mansour
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- * E-mail:
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33
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Wolfmeier H, Mansour SC, Liu LT, Pletzer D, Draeger A, Babiychuk EB, Hancock REW. Liposomal Therapy Attenuates Dermonecrosis Induced by Community-Associated Methicillin-Resistant Staphylococcus aureus by Targeting α-Type Phenol-Soluble Modulins and α-Hemolysin. EBioMedicine 2018; 33:211-217. [PMID: 29936135 PMCID: PMC6085503 DOI: 10.1016/j.ebiom.2018.06.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/05/2018] [Accepted: 06/12/2018] [Indexed: 12/31/2022] Open
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), typified by the pulse-field type USA300, is an emerging endemic pathogen that is spreading rapidly among healthy people. CA-MRSA causes skin and soft tissue infections, life-threatening necrotizing pneumonia and sepsis, and is remarkably resistant to many antibiotics. Here we show that engineered liposomes composed of naturally occurring sphingomyelin were able to sequester cytolytic toxins secreted by USA300 and prevent necrosis of human erythrocytes, peripheral blood mononuclear cells and bronchial epithelial cells. Mass spectrometric analysis revealed the capture by liposomes of phenol-soluble modulins, α-hemolysin and other toxins. Sphingomyelin liposomes prevented hemolysis induced by pure phenol-soluble modulin-α3, one of the main cytolytic components in the USA300 secretome. In contrast, sphingomyelin liposomes harboring a high cholesterol content (66 mol/%) were unable to protect human cells from phenol-soluble modulin-α3-induced lysis, however these liposomes efficiently sequestered the potent staphylococcal toxin α-hemolysin. In a murine cutaneous abscess model, a single dose of either type of liposomes was sufficient to significantly decrease tissue dermonecrosis. Our results provide further insights into the promising potential of tailored liposomal therapy in the battle against infectious diseases.
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Affiliation(s)
- Heidi Wolfmeier
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, V6T1Z4 Vancouver, British Columbia, Canada
| | - Sarah C Mansour
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, V6T1Z4 Vancouver, British Columbia, Canada
| | - Leo T Liu
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, V6T1Z4 Vancouver, British Columbia, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, V6T1Z4 Vancouver, British Columbia, Canada
| | - Annette Draeger
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3000 Bern, Switzerland
| | - Eduard B Babiychuk
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3000 Bern, Switzerland
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 2259 Lower Mall Research Station, V6T1Z4 Vancouver, British Columbia, Canada.
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34
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Luscher A, Moynié L, Auguste PS, Bumann D, Mazza L, Pletzer D, Naismith JH, Köhler T. TonB-Dependent Receptor Repertoire of Pseudomonas aeruginosa for Uptake of Siderophore-Drug Conjugates. Antimicrob Agents Chemother 2018; 62:e00097-18. [PMID: 29555629 PMCID: PMC5971595 DOI: 10.1128/aac.00097-18] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/12/2018] [Indexed: 12/22/2022] Open
Abstract
The conjugation of siderophores to antimicrobial molecules is an attractive strategy to overcome the low outer membrane permeability of Gram-negative bacteria. In this Trojan horse approach, the transport of drug conjugates is redirected via TonB-dependent receptors (TBDR), which are involved in the uptake of essential nutrients, including iron. Previous reports have demonstrated the involvement of the TBDRs PiuA and PirA from Pseudomonas aeruginosa and their orthologues in Acinetobacter baumannii in the uptake of siderophore-beta-lactam drug conjugates. By in silico screening, we further identified a PiuA orthologue, termed PiuD, present in clinical isolates, including strain LESB58. The piuD gene in LESB58 is located at the same genetic locus as piuA in strain PAO1. PiuD has a similar crystal structure as PiuA and is involved in the transport of the siderophore-drug conjugates BAL30072, MC-1, and cefiderocol in strain LESB58. To screen for additional siderophore-drug uptake systems, we overexpressed 28 of the 34 TBDRs of strain PAO1 and identified PfuA, OptE, OptJ, and the pyochelin receptor FptA as novel TBDRs conferring increased susceptibility to siderophore-drug conjugates. The existence of a TBDR repertoire in P. aeruginosa able to transport siderophore-drug molecules potentially decreases the likelihood of resistance emergence during therapy.
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Affiliation(s)
- Alexandre Luscher
- Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Lucile Moynié
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews, Fife, Scotland, United Kingdom
| | | | - Dirk Bumann
- Biozentrum, University of Basel, Basel, Switzerland
| | - Lena Mazza
- Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | | | - James H Naismith
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews, Fife, Scotland, United Kingdom
| | - Thilo Köhler
- Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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Abstract
Microbial biofilms, which are elaborate and highly resistant microbial aggregates formed on surfaces or medical devices, cause two-thirds of infections and constitute a serious threat to public health. Immunocompromised patients, individuals who require implanted devices, artificial limbs, organ transplants, or external life support and those with major injuries or burns, are particularly prone to become infected. Antibiotics, the mainstay treatments of bacterial infections, have often proven ineffective in the fight against microbes when growing as biofilms, and to date, no antibiotic has been developed for use against biofilm infections. Antibiotic resistance is rising, but biofilm-mediated multidrug resistance transcends this in being adaptive and broad spectrum and dependent on the biofilm growth state of organisms. Therefore, the treatment of biofilms requires drug developers to start thinking outside the constricted "antibiotics" box and to find alternative ways to target biofilm infections. Here, we highlight recent approaches for combating biofilms focusing on the eradication of preformed biofilms, including electrochemical methods, promising antibiofilm compounds and the recent progress in drug delivery strategies to enhance the bioavailability and potency of antibiofilm agents.
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Affiliation(s)
- Heidi Wolfmeier
- Department of Microbiology and Immunology, Center for Microbial Diseases
and Immunity Research, University of British Columbia, Room 232, 2259
Lower Mall Research Station, Vancouver, British Columbia V6T 1Z4, Canada
| | - Daniel Pletzer
- Department of Microbiology and Immunology, Center for Microbial Diseases
and Immunity Research, University of British Columbia, Room 232, 2259
Lower Mall Research Station, Vancouver, British Columbia V6T 1Z4, Canada
| | - Sarah C. Mansour
- Department of Microbiology and Immunology, Center for Microbial Diseases
and Immunity Research, University of British Columbia, Room 232, 2259
Lower Mall Research Station, Vancouver, British Columbia V6T 1Z4, Canada
| | - Robert E. W. Hancock
- Department of Microbiology and Immunology, Center for Microbial Diseases
and Immunity Research, University of British Columbia, Room 232, 2259
Lower Mall Research Station, Vancouver, British Columbia V6T 1Z4, Canada
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Pletzer D, Wolfmeier H, Bains M, Hancock REW. Synthetic Peptides to Target Stringent Response-Controlled Virulence in a Pseudomonas aeruginosa Murine Cutaneous Infection Model. Front Microbiol 2017; 8:1867. [PMID: 29021784 PMCID: PMC5623667 DOI: 10.3389/fmicb.2017.01867] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/13/2017] [Indexed: 02/05/2023] Open
Abstract
Microorganisms continuously monitor their surroundings and adaptively respond to environmental cues. One way to cope with various stress-related situations is through the activation of the stringent stress response pathway. In Pseudomonas aeruginosa this pathway is controlled and coordinated by the activity of the RelA and SpoT enzymes that metabolize the small nucleotide secondary messenger molecule (p)ppGpp. Intracellular ppGpp concentrations are crucial in mediating adaptive responses and virulence. Targeting this cellular stress response has recently been the focus of an alternative approach to fight antibiotic resistant bacteria. Here, we examined the role of the stringent response in the virulence of P. aeruginosa PAO1 and the Liverpool epidemic strain LESB58. A ΔrelA/ΔspoT double mutant showed decreased cytotoxicity toward human epithelial cells, exhibited reduced hemolytic activity, and caused down-regulation of the expression of the alkaline protease aprA gene in stringent response mutants grown on blood agar plates. Promoter fusions of relA or spoT to a bioluminescence reporter gene revealed that both genes were expressed during the formation of cutaneous abscesses in mice. Intriguingly, virulence was attenuated in vivo by the ΔrelA/ΔspoT double mutant, but not the relA mutant nor the ΔrelA/ΔspoT complemented with either gene. Treatment of a cutaneous P. aeruginosa PAO1 infection with anti-biofilm peptides increased animal welfare, decreased dermonecrotic lesion sizes, and reduced bacterial numbers recovered from abscesses, resembling the phenotype of the ΔrelA/ΔspoT infection. It was previously demonstrated by our lab that ppGpp could be targeted by synthetic peptides; here we demonstrated that spoT promoter activity was suppressed during cutaneous abscess formation by treatment with peptides DJK-5 and 1018, and that a peptide-treated relA complemented stringent response double mutant strain exhibited reduced peptide susceptibility. Overall these data strongly indicated that synthetic peptides target the P. aeruginosa stringent response in vivo and thus offer a promising novel therapeutic approach.
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Affiliation(s)
- Daniel Pletzer
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Heidi Wolfmeier
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Manjeet Bains
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Robert E W Hancock
- Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
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Pothula KR, Dhanasekar NN, Lamichhane U, Younas F, Pletzer D, Benz R, Winterhalter M, Kleinekathöfer U. Single Residue Acts as Gate in OccK Channels. J Phys Chem B 2017; 121:2614-2621. [DOI: 10.1021/acs.jpcb.7b01787] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Karunakar R. Pothula
- Department
of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Naresh N. Dhanasekar
- Department
of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Usha Lamichhane
- Department
of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Farhan Younas
- Department
of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Daniel Pletzer
- Department
of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Roland Benz
- Department
of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Mathias Winterhalter
- Department
of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department
of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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Chalhoub H, Pletzer D, Weingart H, Braun Y, Tunney MM, Elborn JS, Rodriguez-Villalobos H, Plésiat P, Kahl BC, Denis O, Winterhalter M, Tulkens PM, Van Bambeke F. Mechanisms of intrinsic resistance and acquired susceptibility of Pseudomonas aeruginosa isolated from cystic fibrosis patients to temocillin, a revived antibiotic. Sci Rep 2017; 7:40208. [PMID: 28091521 PMCID: PMC5238406 DOI: 10.1038/srep40208] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 12/01/2016] [Indexed: 12/29/2022] Open
Abstract
The β-lactam antibiotic temocillin (6-α-methoxy-ticarcillin) shows stability to most extended spectrum β-lactamases, but is considered inactive against Pseudomonas aeruginosa. Mutations in the MexAB-OprM efflux system, naturally occurring in cystic fibrosis (CF) isolates, have been previously shown to reverse this intrinsic resistance. In the present study, we measured temocillin activity in a large collection (n = 333) of P. aeruginosa CF isolates. 29% of the isolates had MICs ≤ 16 mg/L (proposed clinical breakpoint for temocillin). Mutations were observed in mexA or mexB in isolates for which temocillin MIC was ≤512 mg/L (nucleotide insertions or deletions, premature termination, tandem repeat, nonstop, and missense mutations). A correlation was observed between temocillin MICs and efflux rate of N-phenyl-1-naphthylamine (MexAB-OprM fluorescent substrate) and extracellular exopolysaccharide abundance (contributing to a mucoid phenotype). OpdK or OpdF anion-specific porins expression decreased temocillin MIC by ~1 two-fold dilution only. Contrarily to the common assumption that temocillin is inactive on P. aeruginosa, we show here clinically-exploitable MICs on a non-negligible proportion of CF isolates, explained by a wide diversity of mutations in mexA and/or mexB. In a broader context, this work contributes to increase our understanding of MexAB-OprM functionality and help delineating how antibiotics interact with MexA and MexB.
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Affiliation(s)
- Hussein Chalhoub
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Daniel Pletzer
- Life Sciences, School of Engineering and Science, Jacobs University, Bremen, Germany
| | - Helge Weingart
- Life Sciences, School of Engineering and Science, Jacobs University, Bremen, Germany
| | - Yvonne Braun
- Life Sciences, School of Engineering and Science, Jacobs University, Bremen, Germany
| | - Michael M Tunney
- CF &Airways Microbiology Research Group, Queen's University Belfast, Belfast, UK
| | - J Stuart Elborn
- CF &Airways Microbiology Research Group, Queen's University Belfast, Belfast, UK
| | - Hector Rodriguez-Villalobos
- Laboratoire de microbiologie, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Patrick Plésiat
- Laboratoire de bactériologie, Hôpital Jean Minjoz, Besançon, France
| | | | - Olivier Denis
- Laboratoire de microbiologie, Hôpital Erasme, Université libre de Bruxelles, Brussels, Belgium
| | - Mathias Winterhalter
- Life Sciences, School of Engineering and Science, Jacobs University, Bremen, Germany
| | - Paul M Tulkens
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Françoise Van Bambeke
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
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Abdallah K, Hartman K, Pletzer D, Zhurina D, Ullrich MS. The bacteriophage-derived transcriptional regulator, LscR, activates the expression of levansucrase genes in Pseudomonas syringae. Mol Microbiol 2016; 102:1062-1074. [PMID: 27664099 DOI: 10.1111/mmi.13536] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2016] [Indexed: 11/30/2022]
Abstract
Synthesis of the exopolysaccharide levan occurs in the bacterial blight pathogen of soybean, Pseudomonas syringae pv. glycinea PG4180, when this bacterium encounters moderate to high concentrations of sucrose inside its host plant. The process is mediated by the temperature-dependent expression and secretion of two levansucrases, LscB and LscC. Previous studies showed the importance of a prophage-associated promoter element in driving the expression of levansucrase genes. Herein, heterologous screening for transcriptional activators revealed that the prophage-borne transcriptional regulator, LscR, from P. syringae mediates expression of levansucrase. A lscR-deficient mutant was generated and exhibited a levan-negative phenotype when grown on a sucrose-rich medium. This phenotype was confirmed by zymographic analysis and Western blots which demonstrated absence of levansucrase in the supernatant and total cell lysates. Transcriptional analysis showed a down-regulation of expression levels of levansucrase and glycosyl hydrolase genes in the lscR-deficient mutant. Ultimately, a direct binding of LscR to the promoter region of levansucrase was demonstrated using electrophoretic mobility shift assays allowing to conclude that a bacteriophage-derived regulator dictates expression of bacterial genes involved in in planta fitness.
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Affiliation(s)
- Khaled Abdallah
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany
| | - Katharina Hartman
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany
| | - Daniel Pletzer
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany
| | - Daria Zhurina
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany
| | - Matthias S Ullrich
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany
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Mansour SC, Pletzer D, de la Fuente-Núñez C, Kim P, Cheung GYC, Joo HS, Otto M, Hancock REW. Bacterial Abscess Formation Is Controlled by the Stringent Stress Response and Can Be Targeted Therapeutically. EBioMedicine 2016; 12:219-226. [PMID: 27658736 PMCID: PMC5078632 DOI: 10.1016/j.ebiom.2016.09.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/12/2016] [Accepted: 09/16/2016] [Indexed: 01/08/2023] Open
Abstract
Cutaneous abscess infections are difficult to treat with current therapies and alternatives to conventional antibiotics are needed. Understanding the regulatory mechanisms that govern abscess pathology should reveal therapeutic interventions for these recalcitrant infections. Here we demonstrated that the stringent stress response employed by bacteria to cope and adapt to environmental stressors was essential for the formation of lesions, but not bacterial growth, in a methicillin resistant Staphylococcus aureus (MRSA) cutaneous abscess mouse model. To pharmacologically confirm the role of the stringent response in abscess formation, a cationic peptide that causes rapid degradation of the stringent response mediator, guanosine tetraphosphate (ppGpp), was employed. The therapeutic application of this peptide strongly inhibited lesion formation in mice infected with Gram-positive MRSA and Gram-negative Pseudomonas aeruginosa. Overall, we provide insights into the mechanisms governing abscess formation and a paradigm for treating multidrug resistant cutaneous abscesses. Universal stringent stress response mediators drive abscess formation. Targeting stress response reduces the severity of cutaneous abscess infections. Pharmacological suppression of S. aureus cutaneous toxin production. Paradigm for treating Gram-positive and Gram-negative bacterial abscess infections.
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Affiliation(s)
- Sarah C Mansour
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - César de la Fuente-Núñez
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Paul Kim
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20814, United States
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20814, United States
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20814, United States
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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Pletzer D, Coleman SR, Hancock RE. Anti-biofilm peptides as a new weapon in antimicrobial warfare. Curr Opin Microbiol 2016; 33:35-40. [PMID: 27318321 DOI: 10.1016/j.mib.2016.05.016] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 01/30/2023]
Abstract
Microorganisms growing in a biofilm state are very resilient in the face of treatment by many antimicrobial agents. Biofilm infections are a significant problem in chronic and long-term infections, including those colonizing medical devices and implants. Anti-biofilm peptides represent a very promising approach to treat biofilm-related infections and have an extraordinary ability to interfere with various stages of the biofilm growth mode. Anti-biofilm peptides possess promising broad-spectrum activity in killing both Gram-positive and Gram-negative bacteria in biofilms, show strong synergy with conventional antibiotics, and act by targeting a universal stringent stress response. Understanding downstream processes at the molecular level will help to develop and design peptides with increased activity. Anti-biofilm peptides represent a novel, exciting approach to treating recalcitrant bacterial infections.
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Affiliation(s)
- Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Shannon R Coleman
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Robert Ew Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.
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Pletzer D, Braun Y, Weingart H. Swarming motility is modulated by expression of the putative xenosiderophore transporter SppR-SppABCD in Pseudomonas aeruginosa PA14. Antonie Van Leeuwenhoek 2016; 109:737-53. [PMID: 26995781 DOI: 10.1007/s10482-016-0675-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/03/2016] [Indexed: 12/14/2022]
Abstract
In the present study, we characterised the putative peptide ABC transporter SppABCD, which is co-transcribed with the TonB-dependent receptor SppR in Pseudomonas aeruginosa PA14. However, our data show that this transporter complex is not involved in the uptake of peptides. The fact that the TonB-dependent receptor SppR is regulated by an iron starvation ECF sigma factor suggested that this transporter is probably involved in the uptake of xenosiderophores. Therefore, we screened culture supernatants of 23 siderophore-producing bacteria for their ability to induce the expression of the SppR-regulating ECF sigma factor. However, none of them had an effect on the expression of this ECF sigma factor. Since the spp operon is not expressed under standard laboratory conditions, we overexpressed it from plasmids in PA14, which led to an impairment of its swarming motility on semisolid agar. Since we excluded the possibility that the uptake of a culture medium component was responsible for the observed phenotype, we hypothesize that the Spp transport system is involved in the uptake of a compound from the periplasmic space or a compound secreted by P. aeruginosa. Furthermore, we found that rhamnolipid synthesis was decreased while biofilm and exopolysaccharide synthesis was slightly increased upon overexpression of the spp operon. Moreover, we observed an impact of spp overexpression on regulation of genes involved in siderophore and phenazine biosynthesis.
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Affiliation(s)
- Daniel Pletzer
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany.
- R.E.W. Hancock Laboratory, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.
| | - Yvonne Braun
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Helge Weingart
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
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Pletzer D, Stahl A, Oja AE, Weingart H. Role of the cell envelope stress regulators BaeR and CpxR in control of RND-type multidrug efflux pumps and transcriptional cross talk with exopolysaccharide synthesis in Erwinia amylovora. Arch Microbiol 2015; 197:761-72. [DOI: 10.1007/s00203-015-1109-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 01/31/2023]
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Mehmood A, Abdallah K, Khandekar S, Zhurina D, Srivastava A, Al-Karablieh N, Alfaro-Espinoza G, Pletzer D, Ullrich MS. Expression of extra-cellular levansucrase in Pseudomonas syringae is controlled by the in planta fitness-promoting metabolic repressor HexR. BMC Microbiol 2015; 15:48. [PMID: 25886911 PMCID: PMC4357207 DOI: 10.1186/s12866-015-0349-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 01/15/2015] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Pseudomonas syringae pv. glycinea PG4180 causes bacterial blight on soybean plants and enters the leaf tissue through stomata or open wounds, where it encounters a sucrose-rich milieu. Sucrose is utilized by invading bacteria via the secreted enzyme, levansucrase (Lsc), liberating glucose and forming the polyfructan levan. P. syringae PG4180 possesses two functional lsc alleles transcribed at virulence-promoting low temperatures. RESULTS We hypothesized that transcription of lsc is controlled by the hexose metabolism repressor, HexR, since potential HexR binding sites were identified upstream of both lsc genes. A hexR mutant of PG4180 was significantly growth-impaired when incubated with sucrose or glucose as sole carbon source, but exhibited wild type growth when arabinose was provided. Analyses of lsc expression resulted in higher transcript and protein levels in the hexR mutant as compared to the wild type. The hexR mutant's ability to multiply in planta was reduced. HexR did not seem to impact hrp gene expression as evidenced by the hexR mutant's unaltered hypersensitive response in tobacco and its unmodified protein secretion pattern as compared to the wild type under hrp-inducing conditions. CONCLUSIONS Our data suggested a co-regulation of genes involved in extra-cellular sugar acquisition with those involved in intra-cellular energy-providing metabolic pathways in P. syringae.
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Affiliation(s)
- Amna Mehmood
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
| | - Khaled Abdallah
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
| | - Shaunak Khandekar
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
| | - Daria Zhurina
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
| | - Abhishek Srivastava
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
| | - Nehaya Al-Karablieh
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
- Hamdi Mango Center for Scientific Research, The University of Jordan, P.O. Box 13507, Amman, 11942, Jordan.
| | - Gabriela Alfaro-Espinoza
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
| | - Daniel Pletzer
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
| | - Matthias S Ullrich
- Molecular Life Science Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
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Karar MGE, Pletzer D, Jaiswal R, Weingart H, Kuhnert N. Identification, characterization, isolation and activity against Escherichia coli of quince (Cydonia oblonga) fruit polyphenols. Food Res Int 2014. [DOI: 10.1016/j.foodres.2013.10.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Pletzer D, Lafon C, Braun Y, Köhler T, Page MGP, Mourez M, Weingart H. High-throughput screening of dipeptide utilization mediated by the ABC transporter DppBCDF and its substrate-binding proteins DppA1-A5 in Pseudomonas aeruginosa. PLoS One 2014; 9:e111311. [PMID: 25338022 PMCID: PMC4206461 DOI: 10.1371/journal.pone.0111311] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/23/2014] [Indexed: 11/18/2022] Open
Abstract
In this study, we show that the dppBCDF operon of Pseudomonas aeruginosa PA14 encodes an ABC transporter responsible for the utilization of di/tripeptides. The substrate specificity of ABC transporters is determined by its associated substrate-binding proteins (SBPs). Whereas in E. coli only one protein, DppA, determines the specificity of the transporter, five orthologous SBPs, DppA1-A5 are present in P. aeruginosa. Multiple SBPs might broaden the substrate specificity by increasing the transporter capacity. We utilized the Biolog phenotype MicroArray technology to investigate utilization of di/tripeptides in mutants lacking either the transport machinery or all of the five SBPs. This high-throughput method enabled us to screen hundreds of dipeptides with various side-chains, and subsequently, to determine the substrate profile of the dipeptide permease. The substrate spectrum of the SBPs was elucidated by complementation of a penta mutant, deficient of all five SBPs, with plasmids carrying individual SBPs. It became apparent that some dipeptides were utilized with different affinity for each SBP. We found that DppA2 shows the highest flexibility on substrate recognition and that DppA2 and DppA4 have a higher tendency to utilize tripeptides. DppA5 was not able to complement the penta mutant under our screening conditions. Phaseolotoxin, a toxic tripeptide inhibiting the enzyme ornithine carbamoyltransferase, is also transported into P. aeruginosa via the DppBCDF permease. The SBP DppA1, and with much greater extend DppA3, are responsible for delivering the toxin to the permease. Our results provide a first overview of the substrate pattern of the ABC dipeptide transport machinery in P. aeruginosa.
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Affiliation(s)
- Daniel Pletzer
- Jacobs University Bremen, School of Engineering and Science, Bremen, Germany
| | - Corinne Lafon
- Sanofi-Aventis R&D, Infectious Diseases Therapeutic Unit, Toulouse, France
| | - Yvonne Braun
- Jacobs University Bremen, School of Engineering and Science, Bremen, Germany
| | - Thilo Köhler
- Department of Microbiology and Molecular Medicine and Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland
| | | | - Michael Mourez
- Sanofi-Aventis R&D, Infectious Diseases Therapeutic Unit, Toulouse, France
| | - Helge Weingart
- Jacobs University Bremen, School of Engineering and Science, Bremen, Germany
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Johnston CD, Bannantine JP, Govender R, Endersen L, Pletzer D, Weingart H, Coffey A, O'Mahony J, Sleator RD. Enhanced expression of codon optimized Mycobacterium avium subsp. paratuberculosis antigens in Lactobacillus salivarius. Front Cell Infect Microbiol 2014; 4:120. [PMID: 25237653 PMCID: PMC4154528 DOI: 10.3389/fcimb.2014.00120] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 08/15/2014] [Indexed: 01/03/2023] Open
Abstract
It is well documented that open reading frames containing high GC content show poor expression in A+T rich hosts. Specifically, G+C-rich codon usage is a limiting factor in heterologous expression of Mycobacterium avium subsp. paratuberculosis (MAP) proteins using Lactobacillus salivarius. However, re-engineering opening reading frames through synonymous substitutions can offset codon bias and greatly enhance MAP protein production in this host. In this report, we demonstrate that codon-usage manipulation of MAP2121c can enhance the heterologous expression of the major membrane protein (MMP), analogous to the form in which it is produced natively by MAP bacilli. When heterologously over-expressed, antigenic determinants were preserved in synthetic MMP proteins as shown by monoclonal antibody mediated ELISA. Moreover, MMP is a membrane protein in MAP, which is also targeted to the cellular surface of recombinant L. salivarius at levels comparable to MAP. Additionally, we previously engineered MAP3733c (encoding MptD) and show herein that MptD displays the tendency to associate with the cytoplasmic membrane boundary under confocal microscopy and the intracellularly accumulated protein selectively adheres to the MptD-specific bacteriophage fMptD. This work demonstrates there is potential for L. salivarius as a viable antigen delivery vehicle for MAP, which may provide an effective mucosal vaccine against Johne's disease.
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Affiliation(s)
| | - John P Bannantine
- United States Department of Agriculture - Agricultural Research Service, National Animal Disease Center Ames, IA, USA
| | - Rodney Govender
- Biological Sciences Department, Cork Institute of Technology Cork, Ireland
| | - Lorraine Endersen
- Biological Sciences Department, Cork Institute of Technology Cork, Ireland
| | - Daniel Pletzer
- School of Engineering and Science, Jacobs University Bremen Bremen, Germany
| | - Helge Weingart
- School of Engineering and Science, Jacobs University Bremen Bremen, Germany
| | - Aidan Coffey
- Biological Sciences Department, Cork Institute of Technology Cork, Ireland
| | - Jim O'Mahony
- Biological Sciences Department, Cork Institute of Technology Cork, Ireland
| | - Roy D Sleator
- Biological Sciences Department, Cork Institute of Technology Cork, Ireland
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Pletzer D, Weingart H. Characterization and regulation of the resistance-nodulation-cell division-type multidrug efflux pumps MdtABC and MdtUVW from the fire blight pathogen Erwinia amylovora. BMC Microbiol 2014; 14:185. [PMID: 25012600 PMCID: PMC4107485 DOI: 10.1186/1471-2180-14-185] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 07/03/2014] [Indexed: 12/01/2022] Open
Abstract
Background The Gram-negative bacterium Erwinia amylovora is the causal agent of the devastating disease fire blight in rosaceous plants such as apple, pear, quince, raspberry, and cotoneaster. In order to survive and multiply in a host, microbes must be able to circumvent the toxic effects of antimicrobial plant compounds, such as flavonoids and tannins. E. amylovora uses multidrug efflux transporters that recognize and actively export toxic compounds out of the cells. Here, two heterotrimeric resistance-nodulation-cell division (RND)-type multidrug efflux pumps, MdtABC and MdtUVW, from E. amylovora were identified. These RND systems are unusual in that they contain two different RND proteins forming a functional pump. Results To find the substrate specificities of the two efflux systems, we overexpressed the transporters in a hypersensitive mutant lacking the major RND pump AcrB. Both transporters mediated resistance to several flavonoids, fusidic acid and novobiocin. Additionally, MdtABC mediated resistance towards josamycin, bile salts and silver nitrate, and MdtUVW towards clotrimazole. The ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock was reduced. Quantitative RT-PCR analyses revealed that the expression of the transporter genes was induced during infection of apple rootstock. The polyphenolic plant compound tannin, as well as the heavy metal salt tungstate was found to induce the expression of mdtABC. Finally, the expression of the mdtABC genes was shown to be regulated by BaeR, the response regulator of the two-component system BaeSR, a cell envelope stress response system that controls the adaptive responses to changes in the environment. Conclusions The expression of MdtABC and MdtUVW is induced during growth of E. amylovora in planta. We identified the plant polyphenol tannin as inducer of mdtABC expression. The reduced ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock suggests that the efflux pumps are involved in resistance to plant antimicrobials, maybe including flavonoids, which were identified as substrates of both pumps. Furthermore, we found that the mdtABC operon belongs to the regulon of the two-component regulator BaeR suggesting a role of this RND transporter in the cell envelope stress response of E. amylovora.
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Affiliation(s)
| | - Helge Weingart
- School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany.
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Khandekar S, Srivastava A, Pletzer D, Stahl A, Ullrich MS. The conserved upstream region of lscB/C determines expression of different levansucrase genes in plant pathogen Pseudomonas syringae. BMC Microbiol 2014; 14:79. [PMID: 24670199 PMCID: PMC3973379 DOI: 10.1186/1471-2180-14-79] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/19/2014] [Indexed: 01/07/2023] Open
Abstract
Background Pseudomonas syringae pv. glycinea PG4180 is an opportunistic plant pathogen which causes bacterial blight of soybean plants. It produces the exopolysaccharide levan by the enzyme levansucrase. Levansucrase has three gene copies in PG4180, two of which, lscB and lscC, are expressed while the third, lscA, is cryptic. Previously, nucleotide sequence alignments of lscB/C variants in various P. syringae showed that a ~450-bp phage-associated promoter element (PAPE) including the first 48 nucleotides of the ORF is absent in lscA. Results Herein, we tested whether this upstream region is responsible for the expression of lscB/C and lscA. Initially, the transcriptional start site for lscB/C was determined. A fusion of the PAPE with the ORF of lscA (lscBUpNA) was generated and introduced to a levan-negative mutant of PG4180. Additionally, fusions comprising of the non-coding part of the upstream region of lscB with lscA (lscBUpA) or the upstream region of lscA with lscB (lscAUpB) were generated. Transformants harboring the lscBUpNA or the lscBUpA fusion, respectively, showed levan formation while the transformant carrying lscAUpB did not. qRT-PCR and Western blot analyses showed that lscBUpNA had an expression similar to lscB while lscBUpA had a lower expression. Accuracy of protein fusions was confirmed by MALDI-TOF peptide fingerprinting. Conclusions Our data suggested that the upstream sequence of lscB is essential for expression of levansucrase while the N-terminus of LscB mediates an enhanced expression. In contrast, the upstream region of lscA does not lead to expression of lscB. We propose that lscA might be an ancestral levansucrase variant upstream of which the PAPE got inserted by potentially phage-mediated transposition events leading to expression of levansucrase in P. syringae.
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Affiliation(s)
- Shaunak Khandekar
- Molecular Life Sciences Research Center, Jacobs University Bremen, Campus Ring 1, Bremen, 28759, Germany.
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Pletzer D, Weingart H. Characterization of AcrD, a resistance-nodulation-cell division-type multidrug efflux pump from the fire blight pathogen Erwinia amylovora. BMC Microbiol 2014; 14:13. [PMID: 24443882 PMCID: PMC3915751 DOI: 10.1186/1471-2180-14-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/03/2014] [Indexed: 01/24/2023] Open
Abstract
Background Multidrug efflux pumps are membrane translocases that have the ability to extrude a variety of structurally unrelated compounds from the cell. AcrD, a resistance-nodulation-cell division (RND) transporter, was shown to be involved in efflux of highly hydrophilic aminoglycosides and a limited number of amphiphilic compounds in E. coli. Here, a homologue of AcrD in the plant pathogen and causal agent of fire blight disease Erwinia amylovora was identified. Results The substrate specificity of AcrD was studied by overexpression of the corresponding gene from a high-copy plasmid in E. amylovora Ea1189-3, which is hypersensitive to many drugs due to a deficiency of the major multidrug pump AcrB. AcrD mediated resistance to several amphiphilic compounds including clotrimazole and luteolin, two compounds hitherto not described as substrates of AcrD in enterobacteria. However, AcrD was not able to expel aminoglycosides. An acrD mutant exhibited full virulence on apple rootstock and immature pear fruits. RT-PCR analysis revealed an induction of acrD expression in infected apple tissue but not on pear fruits. Moreover, a direct binding of BaeR, the response regulator of the two-component regulatory system BaeSR, to the acrD promoter was observed as has already been shown in other enterobacteria. Conclusions AcrD from E. amylovora is involved in resistance to a limited number of amphiphilic compounds, but in contrast to AcrD of E. coli, it is not involved in resistance to aminoglycosides. The expression of acrD was up-regulated by addition of the substrates deoxycholate, naringenin, tetracycline and zinc. AcrD appears to be regulated by the BaeSR two-component system, an envelope stress signal transduction pathway.
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Affiliation(s)
| | - Helge Weingart
- School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany.
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