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Scoffone VC, Barbieri G, Irudal S, Trespidi G, Buroni S. New Antimicrobial Strategies to Treat Multi-Drug Resistant Infections Caused by Gram-Negatives in Cystic Fibrosis. Antibiotics (Basel) 2024; 13:71. [PMID: 38247630 PMCID: PMC10812592 DOI: 10.3390/antibiotics13010071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/23/2024] Open
Abstract
People with cystic fibrosis (CF) suffer from recurrent bacterial infections which induce inflammation, lung tissue damage and failure of the respiratory system. Prolonged exposure to combinatorial antibiotic therapies triggers the appearance of multi-drug resistant (MDR) bacteria. The development of alternative antimicrobial strategies may provide a way to mitigate antimicrobial resistance. Here we discuss different alternative approaches to the use of classic antibiotics: anti-virulence and anti-biofilm compounds which exert a low selective pressure; phage therapies that represent an alternative strategy with a high therapeutic potential; new methods helping antibiotics activity such as adjuvants; and antimicrobial peptides and nanoparticle formulations. Their mechanisms and in vitro and in vivo efficacy are described, in order to figure out a complete landscape of new alternative approaches to fight MDR Gram-negative CF pathogens.
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Affiliation(s)
| | | | | | | | - Silvia Buroni
- Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, 27100 Pavia, Italy; (V.C.S.); (G.B.); (S.I.); (G.T.)
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2
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Hogan AM, Rahman ASMZ, Motnenko A, Natarajan A, Maydaniuk DT, León B, Batun Z, Palacios A, Bosch A, Cardona ST. Profiling cell envelope-antibiotic interactions reveals vulnerabilities to β-lactams in a multidrug-resistant bacterium. Nat Commun 2023; 14:4815. [PMID: 37558695 PMCID: PMC10412643 DOI: 10.1038/s41467-023-40494-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 07/28/2023] [Indexed: 08/11/2023] Open
Abstract
The cell envelope of Gram-negative bacteria belonging to the Burkholderia cepacia complex (Bcc) presents unique restrictions to antibiotic penetration. As a consequence, Bcc species are notorious for causing recalcitrant multidrug-resistant infections in immunocompromised individuals. Here, we present the results of a genome-wide screen for cell envelope-associated resistance and susceptibility determinants in a Burkholderia cenocepacia clinical isolate. For this purpose, we construct a high-density, randomly-barcoded transposon mutant library and expose it to 19 cell envelope-targeting antibiotics. By quantifying relative mutant fitness with BarSeq, followed by validation with CRISPR-interference, we profile over a hundred functional associations and identify mediators of antibiotic susceptibility in the Bcc cell envelope. We reveal connections between β-lactam susceptibility, peptidoglycan synthesis, and blockages in undecaprenyl phosphate metabolism. The synergy of the β-lactam/β-lactamase inhibitor combination ceftazidime/avibactam is primarily mediated by inhibition of the PenB carbapenemase. In comparison with ceftazidime, avibactam more strongly potentiates the activity of aztreonam and meropenem in a panel of Bcc clinical isolates. Finally, we characterize in Bcc the iron and receptor-dependent activity of the siderophore-cephalosporin antibiotic, cefiderocol. Our work has implications for antibiotic target prioritization, and for using additional combinations of β-lactam/β-lactamase inhibitors that can extend the utility of current antibacterial therapies.
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Affiliation(s)
- Andrew M Hogan
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Anna Motnenko
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Aakash Natarajan
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Dustin T Maydaniuk
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Beltina León
- CINDEFI, CONICET-CCT La Plata, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Zayra Batun
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Armando Palacios
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Alejandra Bosch
- CINDEFI, CONICET-CCT La Plata, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Silvia T Cardona
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada.
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3
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Ding Y, Hao J, Xiao W, Ye C, Xiao X, Jian C, Tang M, Li G, Liu J, Zeng Z. Role of efflux pumps, their inhibitors, and regulators in colistin resistance. Front Microbiol 2023; 14:1207441. [PMID: 37601369 PMCID: PMC10436536 DOI: 10.3389/fmicb.2023.1207441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/13/2023] [Indexed: 08/22/2023] Open
Abstract
Colistin is highly promising against multidrug-resistant and extensively drug-resistant bacteria clinically. Bacteria are resistant to colistin mainly through mcr and chromosome-mediated lipopolysaccharide (LPS) synthesis-related locus variation. However, the current understanding cannot fully explain the resistance mechanism in mcr-negative colistin-resistant strains. Significantly, the contribution of efflux pumps to colistin resistance remains to be clarified. This review aims to discuss the contribution of efflux pumps and their related transcriptional regulators to colistin resistance in various bacteria and the reversal effect of efflux pump inhibitors on colistin resistance. Previous studies suggested a complex regulatory relationship between the efflux pumps and their transcriptional regulators and LPS synthesis, transport, and modification. Carbonyl cyanide 3-chlorophenylhydrazone (CCCP), 1-(1-naphthylmethyl)-piperazine (NMP), and Phe-Arg-β-naphthylamide (PAβN) all achieved the reversal of colistin resistance, highlighting the role of efflux pumps in colistin resistance and their potential for adjuvant development. The contribution of the efflux pumps to colistin resistance might also be related to specific genetic backgrounds. They can participate in colistin tolerance and heterogeneous resistance to affect the treatment efficacy of colistin. These findings help understand the development of resistance in mcr-negative colistin-resistant strains.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jinbo Liu
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Zhangrui Zeng
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, China
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4
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Zhu S, Yue J, Wang X, Zhang J, Yu M, Zhan Y, Zhu Y, Sy SKB, Lv Z. Metabolomics revealed mechanism for the synergistic effect of sulbactam, polymyxin-B and amikacin combination against Acinetobacter baumannii. Front Microbiol 2023; 14:1217270. [PMID: 37455727 PMCID: PMC10343439 DOI: 10.3389/fmicb.2023.1217270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 06/13/2023] [Indexed: 07/18/2023] Open
Abstract
Introduction The emergence of multidrug-resistant (MDR) Acinetobacter baumannii prompts clinicians to consider treating these infections with polymyxin combination. Methods Metabolomic analysis was applied to investigate the synergistic effects of polymyxin-B, amikacin and sulbactam combination therapy against MDR A. baumannii harboring OXA-23 and other drug resistant genes. The drug concentrations tested were based on their clinical breakpoints: polymyxin-B (2 mg/L), amikacin (16 mg/L), polymyxin-B/amikacin (2/16 mg/L), and polymyxin-B/amikacin/sulbactam (2/16/4 mg/L). Results The triple antibiotic combination significantly disrupted levels of metabolites involved in cell outer membrane structure including fatty acids, glycerophospholipids, nucleotides, amino acids and peptides as early as 15 min after administration. Amikacin and polymyxin-B alone perturbed a large number of metabolites at 15 min and 1 h, respectively, but the changes in metabolites were short-lived lasting for less than 4 h. In contrast, the combination treatment disrupted a large amount of metabolites beyond 4 h. Compared to the double-combination, the addition of sulbactam to polymyxin-B/amikacin combination produce a greater disorder in A. baumannii metabolome that further confer susceptibility of bacteria to the antibiotics. Conclusion The metabolomic analysis identified mechanisms responsible for the synergistic activities of polymyxin-B/amikacin/sulbactam against MDR A. baumannii.
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Affiliation(s)
| | - Jiali Yue
- Ocean University of China, Qingdao, China
| | | | | | - Mingming Yu
- Ocean University of China, Qingdao, China
- Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | | | - Yuanqi Zhu
- Department of Laboratory Medicine, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Sherwin K. B. Sy
- Department of Statistics, State University of Maringá, Maringá, Paraná, Brazil
| | - Zhihua Lv
- Ocean University of China, Qingdao, China
- Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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5
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Pattinson A, Bahia S, Le Gall G, Morris CJ, Harding SV, McArthur M. Using a multi-omic approach to investigate the mechanism of 12-bis-THA activity against Burkholderia thailandensis. Front Microbiol 2023; 13:1092230. [PMID: 37252207 PMCID: PMC10213367 DOI: 10.3389/fmicb.2022.1092230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/28/2022] [Indexed: 05/31/2023] Open
Abstract
Burkholderia pseudomallei is the causative agent of the tropical disease, melioidosis. It is intrinsically resistant to many antimicrobials and treatment requires an onerous regimen of intravenous and orally administered drugs. Relapse of disease and high rates of mortality following treatment are common, demonstrating the need for new anti-Burkholderia agents. The cationic bola-amphiphile, 12,12'-(dodecane-1,12-diyl) bis (9-amino-1,2,3,4-tetrahydroacridinium), referred to as 12-bis-THA, is a molecule with the potential to treat Burkholderia infections. 12-bis-THA spontaneously forms cationic nanoparticles that bind anionic phospholipids in the prokaryotic membrane and are readily internalized. In this study, we examine the antimicrobial activity of 12-bis-THA against strains of Burkholderia thailandensis. As B. pseudomallei produces a polysaccharide capsule we first examined if this extra barrier influenced the activity of 12-bis-THA which is known to act on the bacterial envelope. Therefore two strains of B. thailandensis were selected for further testing, strain E264 which does not produce a capsule and strain E555 which does produce a capsule that is chemically similar to that found in B. pseudomallei. In this study no difference in the minimum inhibitory concentration (MIC) was observed when capsulated (E555) and unencapsulated (E264) strains of B. thailandensis were compared, however time-kill analysis showed that the unencapsulated strain was more susceptible to 12-bis-THA. The presence of the capsule did not affect the membrane permeation of 12-bis-THA at MIC concentrations. Proteomic and metabolomic analyses showed that 12-bis-THA causes a shift in central metabolism away from glycolysis and glyoxylate cycle, and suppressed the production of the F1 domain of ATP synthase. In summary, we provide insight into the molecular mechanisms underpinning the activity of 12-bis-THA against B. thailandensis and discuss its potential for further development.
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Affiliation(s)
- Adam Pattinson
- Norwich Medical School, Bob Champion Building for Research and Education, University of East Anglia, Norwich, United Kingdom
| | - Sandeep Bahia
- School of Pharmacy, University of East Anglia, Norwich, United Kingdom
| | - Gwénaëlle Le Gall
- Norwich Medical School, Bob Champion Building for Research and Education, University of East Anglia, Norwich, United Kingdom
| | | | - Sarah V. Harding
- CBR Division, Defense Science and Technology Laboratory, Salisbury, United Kingdom
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | - Michael McArthur
- Norwich Medical School, Bob Champion Building for Research and Education, University of East Anglia, Norwich, United Kingdom
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6
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A Two-Component-System-Governed Regulon That Includes a β-Lactamase Gene is Responsive to Cell Envelope Disturbance. mBio 2022; 13:e0174922. [PMID: 35968954 PMCID: PMC9426598 DOI: 10.1128/mbio.01749-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
β-Lactamase production facilitates bacterial survival in nature and affects many infection therapies. However, much of its regulation remains unexplored. We used a genetics-based approach to identify a two-component system (TCS) present in a strain of Burkholderia thailandensis essential for the regulated expression of a class A β-lactamase gene, penL, by sensing subtle envelope disturbance caused by β-lactams, polymyxin B, or other chemical agents. The genes encoding stress responses and resistance to various antibiotics were coregulated, as were the catabolic genes that enabled the B. thailandensis strain to grow on penicillin G or phenylacetate, a degradation product of penicillin G. This regulon has likely evolved to facilitate bacterial survival in the soil microbiome that contains a multitude of antibiotic producers. Practically, this regulatory system makes this TCS, which we named BesRS, an excellent drug target for the purpose of increasing antibiotic efficacy in combination therapies for Burkholderia infections.
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Hogan AM, Cardona ST. Gradients in gene essentiality reshape antibacterial research. FEMS Microbiol Rev 2022; 46:fuac005. [PMID: 35104846 PMCID: PMC9075587 DOI: 10.1093/femsre/fuac005] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 01/14/2022] [Accepted: 01/24/2022] [Indexed: 02/03/2023] Open
Abstract
Essential genes encode the processes that are necessary for life. Until recently, commonly applied binary classifications left no space between essential and non-essential genes. In this review, we frame bacterial gene essentiality in the context of genetic networks. We explore how the quantitative properties of gene essentiality are influenced by the nature of the encoded process, environmental conditions and genetic background, including a strain's distinct evolutionary history. The covered topics have important consequences for antibacterials, which inhibit essential processes. We argue that the quantitative properties of essentiality can thus be used to prioritize antibacterial cellular targets and desired spectrum of activity in specific infection settings. We summarize our points with a case study on the core essential genome of the cystic fibrosis pathobiome and highlight avenues for targeted antibacterial development.
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Affiliation(s)
- Andrew M Hogan
- Department of Microbiology, University of Manitoba, 45 Chancellor's Circle, Winnipeg, Manitoba R3T 2N2, Canada
| | - Silvia T Cardona
- Department of Microbiology, University of Manitoba, 45 Chancellor's Circle, Winnipeg, Manitoba R3T 2N2, Canada
- Department of Medical Microbiology and Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Room 543 - 745 Bannatyne Avenue, Winnipeg, Manitoba, R3E 0J9, Canada
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8
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Human Cryptic Host Defence Peptide GVF27 Exhibits Anti-Infective Properties against Biofilm Forming Members of the Burkholderia cepacia Complex. Pharmaceuticals (Basel) 2022; 15:ph15020260. [PMID: 35215373 PMCID: PMC8878536 DOI: 10.3390/ph15020260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 02/01/2022] [Accepted: 02/16/2022] [Indexed: 11/16/2022] Open
Abstract
Therapeutic solutions to counter Burkholderia cepacia complex (Bcc) bacteria are challenging due to their intrinsically high level of antibiotic resistance. Bcc organisms display a variety of potential virulence factors, have a distinct lipopolysaccharide naturally implicated in antimicrobial resistance. and are able to form biofilms, which may further protect them from both host defence peptides (HDPs) and antibiotics. Here, we report the promising anti-biofilm and immunomodulatory activities of human HDP GVF27 on two of the most clinically relevant Bcc members, Burkholderia multivorans and Burkholderia cenocepacia. The effects of synthetic and labelled GVF27 were tested on B. cenocepacia and B. multivorans biofilms, at three different stages of formation, by confocal laser scanning microscopy (CLSM). Assays on bacterial cultures and on human monocytes challenged with B. cenocepacia LPS were also performed. GVF27 exerts, at different stages of formation, anti-biofilm effects towards both Bcc strains, a significant propensity to function in combination with ciprofloxacin, a relevant affinity for LPSs isolated from B. cenocepacia as well as a good propensity to mitigate the release of pro-inflammatory cytokines in human cells pre-treated with the same endotoxin. Overall, all these findings contribute to the elucidation of the main features that a good therapeutic agent directed against these extremely leathery biofilm-forming bacteria should possess.
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9
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O'Leary MK, Sundaram V, LiPuma JJ, Dörr T, Westblade LF, Alabi CA. Mechanism of Action and Resistance Evasion of an Antimicrobial Oligomer against Multidrug-Resistant Gram-Negative Bacteria. ACS APPLIED BIO MATERIALS 2022; 5:1159-1168. [PMID: 35167257 DOI: 10.1021/acsabm.1c01217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The last resort for treating multidrug-resistant (MDR) Pseudomonas aeruginosa and other MDR Gram-negative bacteria is a class of antibiotics called the polymyxins; however, polymyxin-resistant isolates have emerged. In response, antimicrobial peptides (AMPs) and their synthetic mimetics have been investigated as alternative therapeutic options. Oligothioetheramides (oligoTEAs) are a class of synthetic, sequence-defined oligomers composed of N-allylacrylamide monomers and an abiotic dithiol backbone that is resistant to serum degradation. Characteristic of other AMP mimetics, the precise balance between charge and hydrophobicity has afforded cationic oligoTEAs potent antimicrobial activity, particularly for the compound BDT-4G, which consists of a 1,4-butanedithiol backbone and guanidine pendant groups, the latter of which provides a cationic charge at physiological pH. However, the activity and mechanism of cationic oligoTEAs against MDR Gram-negative isolates have yet to be fully investigated. Herein, we demonstrated the potent antimicrobial activity of BDT-4G against clinical isolates of P. aeruginosa with a range of susceptibility profiles, assessed the kinetics of bactericidal activity, and further elucidated its mechanism of action. Activity was also evaluated against a panel of polymyxin-resistant isolates, including intrinsically-resistant species. We demonstrate that BDT-4G can evade some of the mechanisms conferring resistance to polymyxin B and thus may have therapeutic potential.
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Affiliation(s)
- Meghan K O'Leary
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Vishal Sundaram
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - John J LiPuma
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Tobias Dörr
- Department of Microbiology, Cornell University, Ithaca, New York 14853, United States.,Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, United States.,Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York 14853, United States
| | - Lars F Westblade
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York 10065, United States.,Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, New York 10065, United States
| | - Christopher A Alabi
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
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Torres DA, Seth-Smith HMB, Joosse N, Lang C, Dubuis O, Nüesch-Inderbinen M, Hinic V, Egli A. Colistin resistance in Gram-negative bacteria analysed by five phenotypic assays and inference of the underlying genomic mechanisms. BMC Microbiol 2021; 21:321. [PMID: 34798825 PMCID: PMC8605564 DOI: 10.1186/s12866-021-02388-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/09/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Colistin is used against multi-drug resistant pathogens, yet resistance emerges through dissemination of plasmid-mediated genes (mcr) or chromosomal mutation of genes involved in lipopolysaccharide synthesis (i.e. mgrB, phoPQ, pmrCAB). Phenotypic susceptibility testing is challenging due to poor diffusion of colistin in agar media, leading to an underestimation of resistance. Performance of five phenotypic approaches was compared in the context of different molecular mechanisms of resistance. We evaluated Vitek 2® (bioMérieux, AST N242), Colistin MIC Test Strip (Liofilchem Diagnostici), UMIC (Biocentric), and Rapid Polymyxin™ NP test (ELITechGroup) against the standard broth microdilution (BMD) method. We used whole genome sequencing (WGS) to infer molecular resistance mechanisms. We analysed 97 Enterobacterales and non-fermenting bacterial isolates, largely clinical isolates collected up to 2018. Data was analysed by comparing susceptibility categories (susceptible or resistant) and minimal inhibitory concentrations (MIC). Susceptibility category concordance is the percentage of test results sharing the same category to BMD. MIC concordance was calculated similarly but considering ±1 MIC titre error range. We determined genomic diversity by core genome multi locus sequencing typing (cgMLST) and identified putative antimicrobial resistance genes using NCBI and CARD databases, and manual annotation. RESULTS Of 97 isolates, 54 (56%) were resistant with standard BMD. Highest susceptibility category concordance was achieved by Rapid Polymyxin™ NP (98.8%) followed by UMIC (97.9%), Colistin E-test MIC strip (96.9%) and Vitek 2® (95.6%). Highest MIC concordance was achieved by UMIC (80.4%), followed by Vitek 2® (72.5%) and Colistin E-test MIC strip (62.9%). Among resistant isolates, 23/54 (43%) were intrinsically resistant to colistin, whereas 31/54 (57%) isolates had acquired colistin resistance. Of these, mcr-1 was detected in four isolates and mcr-2 in one isolate. Non-synonymous mutations in mgrB, phoQ, pmrA, pmrB, and pmrC genes were encountered in Klebsiella pneumoniae, Escherichia coli, and Acinetobacter bereziniae resistant isolates. Mutations found in mgrB and pmrB were only identified in isolates exhibiting MICs of ≥16 mg/L. CONCLUSIONS The Rapid Polymyxin™ NP test showed highest categorical concordance and the UMIC test provided MIC values with high concordance to BMD. We found colistin resistance in diverse species occurred predominantly through spontaneous chromosomal mutation rather than plasmid-mediated resistance.
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Affiliation(s)
- Diana Albertos Torres
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Helena M B Seth-Smith
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Nicole Joosse
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Unilabs Bern-Mittelland, Bern, Switzerland
| | - Claudia Lang
- Clinical Microbiology, Viollier AG, Allschwil, Switzerland
| | - Olivier Dubuis
- Clinical Microbiology, Viollier AG, Allschwil, Switzerland
| | | | - Vladimira Hinic
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Adrian Egli
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland.
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland.
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11
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Rodríguez AA, Otero-González A, Ghattas M, Ständker L. Discovery, Optimization, and Clinical Application of Natural Antimicrobial Peptides. Biomedicines 2021; 9:1381. [PMID: 34680498 PMCID: PMC8533436 DOI: 10.3390/biomedicines9101381] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 09/28/2021] [Indexed: 12/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are widespread in multicellular organisms. These structurally diverse molecules are produced as the first line of defense against pathogens such as bacteria, viruses, fungi, and parasites. Also known as host defense peptides in higher eukaryotic organisms, AMPs display immunomodulatory and anticancer activities. During the last 30 years, technological advances have boosted the research on antimicrobial peptides, which have also attracted great interest as an alternative to tackling the antimicrobial resistance scenario mainly provoked by some bacterial and fungal pathogens. However, the introduction of natural AMPs in clinical trials faces challenges such as proteolytic digestion, short half-lives, and cytotoxicity upon systemic and oral application. Therefore, some strategies have been implemented to improve the properties of AMPs aiming to be used as effective therapeutic agents. In the present review, we summarize the discovery path of AMPs, focusing on preclinical development, recent advances in chemical optimization and peptide delivery systems, and their introduction into the market.
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Affiliation(s)
- Armando A. Rodríguez
- Core Facility for Functional Peptidomics, Ulm University Medical Center, 89081 Ulm, Germany
- Core Unit of Mass Spectrometry and Proteomics, Ulm University Medical Center, 89081 Ulm, Germany
| | | | - Maretchia Ghattas
- Faculty of Pharmacy and Biotechnology, German University in Cairo (GUC), Cairo 11511, Egypt;
| | - Ludger Ständker
- Core Facility for Functional Peptidomics, Ulm University Medical Center, 89081 Ulm, Germany
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12
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Antibiofilm activity of host defence peptides: complexity provides opportunities. Nat Rev Microbiol 2021; 19:786-797. [PMID: 34183822 DOI: 10.1038/s41579-021-00585-w] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2021] [Indexed: 12/21/2022]
Abstract
Host defence peptides (HDPs) are integral components of innate immunity across all living organisms. These peptides can exert direct antibacterial effects, targeting planktonic cells (referred to as antimicrobial peptides), and exhibit antibiofilm (referred to as antibiofilm peptides), antiviral, antifungal and host-directed immunomodulatory activities. In this Review, we discuss how the complex functional attributes of HDPs provide many opportunities for the development of antimicrobial therapeutics, focusing particularly on their emerging antibiofilm properties. The mechanisms of action of antibiofilm peptides are compared and contrasted with those of antimicrobial peptides. Furthermore, obstacles for the practical translation of candidate peptides into therapeutics and the potential solutions are discussed. Critically, HDPs have the value-added assets of complex functional attributes, particularly antibiofilm and anti-inflammatory activities and their synergy with conventional antibiotics.
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13
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Panta PR, Doerrler WT. A link between pH homeostasis and colistin resistance in bacteria. Sci Rep 2021; 11:13230. [PMID: 34168215 PMCID: PMC8225787 DOI: 10.1038/s41598-021-92718-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/14/2021] [Indexed: 12/15/2022] Open
Abstract
Colistin resistance is complex and multifactorial. DbcA is an inner membrane protein belonging to the DedA superfamily required for maintaining extreme colistin resistance of Burkholderia thailandensis. The molecular mechanisms behind this remain unclear. Here, we report that ∆dbcA displays alkaline pH/bicarbonate sensitivity and propose a role of DbcA in extreme colistin resistance of B. thailandensis by maintaining cytoplasmic pH homeostasis. We found that alkaline pH or presence of sodium bicarbonate displays a synergistic effect with colistin against not only extremely colistin resistant species like B. thailandensis and Serratia marcescens, but also a majority of Gram-negative and Gram-positive bacteria tested, suggesting a link between cytoplasmic pH homeostasis and colistin resistance across species. We found that lowering the level of oxygen in the growth media or supplementation of fermentable sugars such as glucose not only alleviated alkaline pH stress, but also increased colistin resistance in most bacteria tested, likely by avoiding cytoplasmic alkalinization. Our observations suggest a previously unreported link between pH, oxygen, and colistin resistance. We propose that maintaining optimal cytoplasmic pH is required for colistin resistance in a majority of bacterial species, consistent with the emerging link between cytoplasmic pH homeostasis and antibiotic resistance.
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Affiliation(s)
- Pradip R Panta
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - William T Doerrler
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA.
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Modupe SL, Yaa NB, Henaku OE, Ohya K, Masato S, Opare OJ, Baboreka KB. Protected but not from Contamination: Antimicrobial Resistance Profiles of Bacteria from Birds in a Ghanaian Forest Protected Area. ENVIRONMENTAL HEALTH INSIGHTS 2021; 15:11786302211017687. [PMID: 34121841 PMCID: PMC8174002 DOI: 10.1177/11786302211017687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
Resistance to antimicrobial agents is a growing concern in public health. It has been reported in wildlife from several places in the world though wild animals are not normally exposed to clinically used antimicrobial agents. Despite this, very little research has been done in Ghana to determine antimicrobial resistance in wild animals, particularly those in protected areas. In this study, the presence of colistin resistant and multidrug resistant (MDR) gram-negative bacteria in cloacal swabs of wild birds captured in a Ghanaian forest protected area were evaluated. A total of 195 isolates from 138 individual birds were obtained, identified and tested for resistance to colistin. The colistin-resistant isolates were subsequently tested for multidrug resistance to 4 other antimicrobial agents (Oxytetracycline, Streptomycin, Ampicillin and Ciprofloxacin). Colistin resistance was observed in 6.5% (9/138) of the birds and this was seen in only birds that were sampled close to the reception area of the protected area. About 50% of the colistin-resistant isolates were multidrug resistant. AMR isolates were obtained from birds that have been documented to show an insectivorous or omnivorous feeding preference. Data obtained from the study suggests that AMR and MDR occurred in wild birds from the Conservation Area and supports the claim that proximity to human impacted habitats (settlements/farmlands) increased the likelihood of carriage of AMR. Though the routes of transmission remain unclear, there is potential for spread from the wild birds to other wild/domestic animals and possibly back to humans.
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Affiliation(s)
| | - Ntiamoa-Baidu Yaa
- Centre for African Wetlands, University of Ghana, Legon, Ghana
- Department of Animal Biology and Conservation Science, University of Ghana, Legon, Ghana
| | - Owusu Erasmus Henaku
- Department of Animal Biology and Conservation Science, University of Ghana, Legon, Ghana
- Centre for Climate Change and Sustainability Studies, University of Ghana, Legon, Ghana
| | - Kenji Ohya
- Department of Applied Veterinary Sciences, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Suzuki Masato
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Odoi Justice Opare
- Department of Applied Veterinary Sciences, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
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15
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CLEAR - Contact lens wettability, cleaning, disinfection and interactions with tears. Cont Lens Anterior Eye 2021; 44:157-191. [DOI: 10.1016/j.clae.2021.02.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/15/2022]
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16
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The ABC-Type Efflux Pump MacAB Is Involved in Protection of Serratia marcescens against Aminoglycoside Antibiotics, Polymyxins, and Oxidative Stress. mSphere 2021; 6:6/2/e00033-21. [PMID: 33692192 PMCID: PMC8546677 DOI: 10.1128/msphere.00033-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Serratia marcescens is an emerging pathogen with increasing clinical importance due to its intrinsic resistance to several classes of antibiotics. The chromosomally encoded drug efflux pumps contribute to antibiotic resistance and represent a major challenge for the treatment of bacterial infections. The ABC-type efflux pump MacAB was previously linked to macrolide resistance in Escherichia coli and Salmonella enterica serovar Typhimurium. The role of the MacAB homolog in antibiotic resistance of S. marcescens is currently unknown. We found that an S. marcescens mutant lacking the MacAB pump did not show increased sensitivity to the macrolide antibiotic erythromycin but was significantly more sensitive to aminoglycoside antibiotics and polymyxins. We also showed that, in addition to its role in drug efflux, the MacAB efflux pump is required for swimming motility and biofilm formation. We propose that the motility defect of the ΔmacAB mutant is due, at least in part, to the loss of functional flagella on the bacterial surface. Furthermore, we found that the promoter of the MacAB efflux pump was active during the initial hours of growth in laboratory medium and that its activity was further elevated in the presence of hydrogen peroxide. Finally, we demonstrate a complete loss of ΔmacAB mutant viability in the presence of peroxide, which is fully restored by complementation. Thus, the S. marcescens MacAB efflux pump is essential for survival during oxidative stress and is involved in protection from polymyxins and aminoglycoside antibiotics. IMPORTANCE The opportunistic pathogen Serratia marcescens can cause urinary tract infections, respiratory infections, meningitis, and sepsis in immunocompromised individuals. These infections are challenging to treat due to the intrinsic resistance of S. marcescens to an extensive array of antibiotics. Efflux pumps play a crucial role in protection of bacteria from antimicrobials. The MacAB efflux pump, previously linked to efflux of macrolides in Escherichia coli and protection from oxidative stress in Salmonella enterica serovar Typhimurium, is not characterized in S. marcescens. We show the role of the MacAB efflux pump in S. marcescens protection from aminoglycoside antibiotics and polymyxins, modulation of bacterial motility, and biofilm formation, and we illustrate the essential role for this pump in bacterial survival during oxidative stress. Our findings make the MacAB efflux pump an attractive target for inhibition to gain control over S. marcescens infections.
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Cardoso P, Glossop H, Meikle TG, Aburto-Medina A, Conn CE, Sarojini V, Valery C. Molecular engineering of antimicrobial peptides: microbial targets, peptide motifs and translation opportunities. Biophys Rev 2021; 13:35-69. [PMID: 33495702 PMCID: PMC7817352 DOI: 10.1007/s12551-021-00784-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 01/07/2021] [Indexed: 02/07/2023] Open
Abstract
The global public health threat of antimicrobial resistance has led the scientific community to highly engage into research on alternative strategies to the traditional small molecule therapeutics. Here, we review one of the most popular alternatives amongst basic and applied research scientists, synthetic antimicrobial peptides. The ease of peptide chemical synthesis combined with emerging engineering principles and potent broad-spectrum activity, including against multidrug-resistant strains, has motivated intense scientific focus on these compounds for the past decade. This global effort has resulted in significant advances in our understanding of peptide antimicrobial activity at the molecular scale. Recent evidence of molecular targets other than the microbial lipid membrane, and efforts towards consensus antimicrobial peptide motifs, have supported the rise of molecular engineering approaches and design tools, including machine learning. Beyond molecular concepts, supramolecular chemistry has been lately added to the debate; and helped unravel the impact of peptide self-assembly on activity, including on biofilms and secondary targets, while providing new directions in pharmaceutical formulation through taking advantage of peptide self-assembled nanostructures. We argue that these basic research advances constitute a solid basis for promising industry translation of rationally designed synthetic peptide antimicrobials, not only as novel drugs against multidrug-resistant strains but also as components of emerging antimicrobial biomaterials. This perspective is supported by recent developments of innovative peptide-based and peptide-carrier nanobiomaterials that we also review.
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Affiliation(s)
- Priscila Cardoso
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Australia.,School of Science, RMIT University, Melbourne, Australia
| | - Hugh Glossop
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | | | | | | | | | - Celine Valery
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Australia
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18
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Panta PR, Doerrler WT. A Burkholderia thailandensis DedA Family Membrane Protein Is Required for Proton Motive Force Dependent Lipid A Modification. Front Microbiol 2021; 11:618389. [PMID: 33510730 PMCID: PMC7835334 DOI: 10.3389/fmicb.2020.618389] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2020] [Indexed: 12/18/2022] Open
Abstract
The DedA family is a conserved membrane protein family found in most organisms. A Burkholderia thailandensis DedA family protein, named DbcA, is required for high-level colistin (polymyxin E) resistance, but the mechanism awaits elucidation. Modification of lipopolysaccharide lipid A with the cationic sugar aminoarabinose (Ara4N) is required for colistin resistance and is dependent upon protonmotive force (PMF) dependent transporters. B. thailandensis ΔdbcA lipid A contains only small amounts of Ara4N, likely leading to colistin sensitivity. Two B. thailandensis operons are required for lipid A modification with Ara4N, one needed for biosynthesis of undecaprenyl-P-Ara4N and one for transport of the lipid linked sugar and subsequent lipid A modification. Here, we directed overexpression of each arn operon by genomic insertion of inducible promoters. We found that overexpression of arn operons in ΔdbcA can partially, but not completely, restore Ara4N modification of lipid A and colistin resistance. Artificially increasing the PMF by lowering the pH of the growth media also increased membrane potential, amounts of Ara4N, and colistin resistance of ΔdbcA. In addition, the products of arn operons are essential for acid tolerance, suggesting a physiological function of Ara4N modification. Finally, we show that ΔdbcA is sensitive to bacitracin and expression of a B. thailandensis UppP/BacA homolog (BTH_I1512) can partially restore resistance to bacitracin. Expression of a different UppP/BacA homolog (BTH_I2750) can partially restore colistin resistance, without changing the lipid A profile. This work suggests that maintaining optimal membrane potential at slightly alkaline pH media by DbcA is responsible for proper modification of lipid A by Ara4N and provides evidence of lipid A modification-dependent and -independent mechanisms of colistin resistance in B. thailandensis.
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Affiliation(s)
- Pradip R Panta
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
| | - William T Doerrler
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
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19
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Patrulea V, Borchard G, Jordan O. An Update on Antimicrobial Peptides (AMPs) and Their Delivery Strategies for Wound Infections. Pharmaceutics 2020; 12:E840. [PMID: 32887353 PMCID: PMC7560145 DOI: 10.3390/pharmaceutics12090840] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/22/2020] [Accepted: 08/28/2020] [Indexed: 12/13/2022] Open
Abstract
Bacterial infections occur when wound healing fails to reach the final stage of healing, which is usually hindered by the presence of different pathogens. Different topical antimicrobial agents are used to inhibit bacterial growth due to antibiotic failure in reaching the infected site, which is accompanied very often by increased drug resistance and other side effects. In this review, we focus on antimicrobial peptides (AMPs), especially those with a high potential of efficacy against multidrug-resistant and biofilm-forming bacteria and fungi present in wound infections. Currently, different AMPs undergo preclinical and clinical phase to combat infection-related diseases. AMP dendrimers (AMPDs) have been mentioned as potent microbial agents. Various AMP delivery strategies that are used to combat infection and modulate the healing rate-such as polymers, scaffolds, films and wound dressings, and organic and inorganic nanoparticles-have been discussed as well. New technologies such as Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-associated protein (CRISPR-Cas) are taken into consideration as potential future tools for AMP delivery in skin therapy.
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Affiliation(s)
- Viorica Patrulea
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1 Rue Michel Servet, 1211 Geneva, Switzerland;
- Section of Pharmaceutical Sciences, University of Geneva, 1 Rue Michel Servet, 1211 Geneva, Switzerland
| | - Gerrit Borchard
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1 Rue Michel Servet, 1211 Geneva, Switzerland;
- Section of Pharmaceutical Sciences, University of Geneva, 1 Rue Michel Servet, 1211 Geneva, Switzerland
| | - Olivier Jordan
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1 Rue Michel Servet, 1211 Geneva, Switzerland;
- Section of Pharmaceutical Sciences, University of Geneva, 1 Rue Michel Servet, 1211 Geneva, Switzerland
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20
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Abstract
The causative agent of melioidosis, Burkholderia pseudomallei, a tier 1 select agent, is endemic in Southeast Asia and northern Australia, with increased incidence associated with high levels of rainfall. Increasing reports of this condition have occurred worldwide, with estimates of up to 165,000 cases and 89,000 deaths per year. The ecological niche of the organism has yet to be clearly defined, although the organism is associated with soil and water. The culture of appropriate clinical material remains the mainstay of laboratory diagnosis. Identification is best done by phenotypic methods, although mass spectrometric methods have been described. Serology has a limited diagnostic role. Direct molecular and antigen detection methods have limited availability and sensitivity. Clinical presentations of melioidosis range from acute bacteremic pneumonia to disseminated visceral abscesses and localized infections. Transmission is by direct inoculation, inhalation, or ingestion. Risk factors for melioidosis include male sex, diabetes mellitus, alcohol abuse, and immunosuppression. The organism is well adapted to intracellular survival, with numerous virulence mechanisms. Immunity likely requires innate and adaptive responses. The principles of management of this condition are drainage and debridement of infected material and appropriate antimicrobial therapy. Global mortality rates vary between 9% and 70%. Research into vaccine development is ongoing.
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Affiliation(s)
- I Gassiep
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - M Armstrong
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
| | - R Norton
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
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21
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Baindara P, Ghosh AK, Mandal SM. Coevolution of Resistance Against Antimicrobial Peptides. Microb Drug Resist 2020; 26:880-899. [PMID: 32119634 DOI: 10.1089/mdr.2019.0291] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are produced by all forms of life, ranging from eukaryotes to prokaryotes, and they are a crucial component of innate immunity, involved in clearing infection by inhibiting pathogen colonization. In the recent past, AMPs received high attention due to the increase of extensive antibiotic resistance by these pathogens. AMPs exhibit a diverse spectrum of activity against bacteria, fungi, parasites, and various types of cancer. AMPs are active against various bacterial pathogens that cause disease in animals and plants. However, because of the coevolution of host and pathogen interaction, bacteria have developed the mechanisms to sense and exhibit an adaptive response against AMPs. These resistance mechanisms are playing an important role in bacterial virulence within the host. Here, we have discussed the different resistance mechanisms used by gram-positive and gram-negative bacteria to sense and combat AMP actions. Understanding the mechanism of AMP resistance may provide directions toward the development of novel therapeutic strategies to control multidrug-resistant pathogens.
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Affiliation(s)
- Piyush Baindara
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ananta K Ghosh
- Department of Biotechnology, Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Santi M Mandal
- Department of Biotechnology, Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, India
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22
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Mitra S, Basu S, Rath S, Sahu SK. Colistin resistance in Gram-negative ocular infections: prevalence, clinical outcome and antibiotic susceptibility patterns. Int Ophthalmol 2020; 40:1307-1317. [DOI: 10.1007/s10792-020-01298-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/20/2020] [Indexed: 10/25/2022]
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Olagnon C, Monjaras Feria J, Grünwald-Gruber C, Blaukopf M, Valvano MA, Kosma P. Synthetic Phosphodiester-Linked 4-Amino-4-deoxy-l-arabinose Derivatives Demonstrate that ArnT is an Inverting Aminoarabinosyl Transferase. Chembiochem 2019; 20:2936-2948. [PMID: 31233657 PMCID: PMC6902282 DOI: 10.1002/cbic.201900349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Indexed: 12/22/2022]
Abstract
4‐Amino‐4‐deoxy‐l‐arabinopyranose (Ara4N) residues have been linked to antibiotic resistance due to reduction of the negative charge in the lipid A and core regions of the bacterial lipopolysaccharide (LPS). To study the enzymatic transfer of Ara4N onto lipid A, which is catalysed by the ArnT transferase, we chemically synthesised a series of anomeric phosphodiester‐linked lipid Ara4N derivatives containing linear aliphatic chains as well as E‐ and Z‐configured monoterpene units. Coupling reactions were based on sugar‐derived H‐phosphonates, followed by oxidation and global deprotection. The enzymatic Ara4N transfer was performed in vitro with crude membranes from a deep‐rough mutant from Escherichia coli as acceptor. Product formation was detected by TLC and LC‐ESI‐QTOF mass spectrometry. Out of seven analogues tested, only the α‐neryl derivative was accepted by the Burkholderia cenocepacia ArnT protein, leading to substitution of the Kdo2‐lipid A acceptor and thus affording evidence that ArnT is an inverting glycosyl transferase that requires the Z‐configured double bond next to the anomeric phosphate moiety. This approach provides an easily accessible donor substrate for biochemical studies relating to modifications of bacterial LPS that modulate antibiotic resistance and immune recognition.
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Affiliation(s)
- Charlotte Olagnon
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Julia Monjaras Feria
- Wellcome-Wolfson Institute of Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, BT9 7BL, Belfast, UK
| | - Clemens Grünwald-Gruber
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Markus Blaukopf
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Miguel A Valvano
- Wellcome-Wolfson Institute of Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, BT9 7BL, Belfast, UK
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190, Vienna, Austria
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Bellotti D, Toniolo M, Dudek D, Mikołajczyk A, Guerrini R, Matera-Witkiewicz A, Remelli M, Rowińska-Żyrek M. Bioinorganic chemistry of calcitermin - the picklock of its antimicrobial activity. Dalton Trans 2019; 48:13740-13752. [PMID: 31475275 DOI: 10.1039/c9dt02869b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Calcitermin, an antimicrobial peptide from the fluid of the human airways, is a well-conserved, 15 amino acid C-terminal cleavage fragment of calgranulin C (VAIALKAAHYHTHKE), which is active under acidic pH conditions (pH 5.4). In an attempt to understand the impact of the coordination of Zn(ii) and Cu(ii) on the biological activity of calcitermin, we mutated each of the histidines with an alanine and studied the thermodynamics, binding mode and antimicrobial activity of wild type calcitermin and its H9A, H11A and H13A mutants and their Zn(ii) and Cu(ii) complexes. Both metals strongly enhance the antimicrobial activity of calcitermin-like peptides, although the link between the minimal inhibitory concentration (MIC) values and the stability, charge or structure of the complexes is not so obvious. As expected, the increase in the number of histidines makes the coordination of both metals more effective. There is no preferred Cu(ii) binding site in calcitermin: the stabilities of the Cu(ii)-H9A and Cu(ii)-H13A complexes are almost identical, while the Cu(ii)-H11A complex (in which two histidines are separated by three amino acids and only one His residue is involved in binding) is less stable. On the other hand, the higher stability of the Zn(ii)-H13A complex with respect to those formed by H9A and H11A suggests a pivotal role of His9 and His11 in Zn(ii) complexation. Impressive MIC breakpoints were obtained, similar and lower than those for commonly used antimicrobial agents that treat Candida albicans (Zn(ii) and Cu(ii) complexes of WT calcitermin and H9A, as well as H9A alone), Enterococcus faecalis (H11A, H13A and their metal complexes) and Staphylococcus aureus (H13A and its complexes).
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Affiliation(s)
- Denise Bellotti
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Luigi Borsari 46, 44121 Ferrara, Italy. and Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wroclaw, Poland
| | - Mattia Toniolo
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Luigi Borsari 46, 44121 Ferrara, Italy.
| | - Dorota Dudek
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wroclaw, Poland
| | - Aleksandra Mikołajczyk
- Screening Laboratory of Biological Activity Test and Collection of Biological Material, Faculty of Pharmacy with Division of Laboratory Diagnostics, Wrocław Medical University, Borowska 211A, 50-556 Wrocław, Poland
| | - Remo Guerrini
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Luigi Borsari 46, 44121 Ferrara, Italy.
| | - Agnieszka Matera-Witkiewicz
- Screening Laboratory of Biological Activity Test and Collection of Biological Material, Faculty of Pharmacy with Division of Laboratory Diagnostics, Wrocław Medical University, Borowska 211A, 50-556 Wrocław, Poland
| | - Maurizio Remelli
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Luigi Borsari 46, 44121 Ferrara, Italy.
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Nosocomial bloodstream infection and the emerging carbapenem-resistant pathogen Ralstonia insidiosa. BMC Infect Dis 2019; 19:334. [PMID: 31014269 PMCID: PMC6480722 DOI: 10.1186/s12879-019-3985-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 04/12/2019] [Indexed: 02/05/2023] Open
Abstract
Background Ralstonia picketti, Ralstonia mannitolilytica, and Ralstonia insidiosa have recently been regarded as emerging pathogens of infectious diseases, in particular as the pathogens responsible for nosocomial infection in immunocompromised patients. R. insidiosa differs from R. picketti and R. mannitolilytica, and its related infections are rarely reported. Methods Clinical data from two nosocomial bloodstream infection cases were extracted and analyzed. The causable isolates were identified by the VITEK 2 Compact system, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and molecular identification methods using PCR with universal and species-specific primers. Antimicrobial susceptibility testing was performed using the broth microdilution method. Both of the isolates were subjected to whole genome sequencing using a HiSeq X10 Sequencer. Antimicrobial resistance genes, virulence factors, and plasmid replicons were identified from assembled genomes. A real-time RT-PCR experiment and a cloning experiment were conducted to explore the related class D β-lactamase-encoding genes. Results Both patients recovered under therapy with antibiotics. Isolates were initially misidentified as R. mannitolilytica by the VITEK 2 Compact system rather than R. insidiosa, as identified by both MALDI-TOF MS and 16S rRNA gene sequencing. Both isolates were resistant to aminoglycosides, β-lactams, and polymyxin B. One isolate harboring blaOXA-570 was resistant to carbapenems. The whole genome sequencing data confirmed species identification based on average nucleotide identity (ANI) and revealed two variants of class D β-lactamase-encoding gene blaOXA (blaOXA-573 and blaOXA-574). The real-time RT-PCR experiment showed no difference in gene expression between blaOXA-570 and blaOXA-573 in our strains. The cloning experiment showed that variant OXA-573 had no carbapenem hydrolase activity. Conclusions We described two cases of nosocomial bloodstream infection caused by R. insidiosa strains. MALDI-TOF MS was cost-effective for rapid species identification. Clinicians should be aware that R. insidiosa can be resistant to commonly used antibiotics, even carbapenems.
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Haney EF, Straus SK, Hancock REW. Reassessing the Host Defense Peptide Landscape. Front Chem 2019; 7:43. [PMID: 30778385 PMCID: PMC6369191 DOI: 10.3389/fchem.2019.00043] [Citation(s) in RCA: 216] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 01/15/2019] [Indexed: 12/18/2022] Open
Abstract
Current research has demonstrated that small cationic amphipathic peptides have strong potential not only as antimicrobials, but also as antibiofilm agents, immune modulators, and anti-inflammatories. Although traditionally termed antimicrobial peptides (AMPs) these additional roles have prompted a shift in terminology to use the broader term host defense peptides (HDPs) to capture the multi-functional nature of these molecules. In this review, we critically examined the role of AMPs and HDPs in infectious diseases and inflammation. It is generally accepted that HDPs are multi-faceted mediators of a wide range of biological processes, with individual activities dependent on their polypeptide sequence. In this context, we explore the concept of chemical space as it applies to HDPs and hypothesize that the various functions and activities of this class of molecule exist on independent but overlapping activity landscapes. Finally, we outline several emerging functions and roles of HDPs and highlight how an improved understanding of these processes can potentially be leveraged to more fully realize the therapeutic promise of HDPs.
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Affiliation(s)
- Evan F Haney
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Suzana K Straus
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
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The Mla Pathway Plays an Essential Role in the Intrinsic Resistance of Burkholderia cepacia Complex Species to Antimicrobials and Host Innate Components. J Bacteriol 2018; 200:JB.00156-18. [PMID: 29986943 DOI: 10.1128/jb.00156-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 07/02/2018] [Indexed: 11/20/2022] Open
Abstract
Antibiotic resistance is a threat to our modern society, and new strategies leading to the identification of new molecules or targets to combat multidrug-resistant pathogens are needed. Species of the genus Burkholderia, including the Burkholderia cepacia complex (Bcc), Burkholderia pseudomallei, and Burkholderia mallei, can be highly pathogenic and are intrinsically resistant to multiple classes of antibiotics. Bcc species are nonetheless sensitive to extracellular products released by Pseudomonas aeruginosa in interspecies competition. We screened for Burkholderia transposon mutants with increased sensitivity to P. aeruginosa spent medium and identified multiple mutants in genes sharing homology with the Mla pathway. Insertional mutants in representative genes of the Bcc Mla pathway had a compromised cell membrane and were more sensitive to various extracellular stresses, including antibiotics and human serum. More precisely, mla mutants in the Bcc species Burkholderia cenocepacia and Burkholderia dolosa were more susceptible to Gram-positive antibiotics (i.e., macrolides and rifampin), fluoroquinolones, tetracyclines, and chloramphenicol. Genetic complementation of mlaC insertional mutants restored cell permeability and resistance to Gram-positive antibiotics. Importantly, Bcc mla mutants were not universally weaker strains since their susceptibilities to other classes of antibiotics were unaffected. Although cell permeability of homologous mla mutants in Escherichia coli or P. aeruginosa was also impaired, they were not more sensitive to Gram-positive antibiotics or other antimicrobials as was observed in Bcc mla mutants. Together, the data suggest that the Mla pathway in Burkholderia may play a different biological role, which could potentially represent a Burkholderia-specific drug target in combination therapy with antibiotic adjuvants.IMPORTANCE The outer membrane of Gram-negative bacteria acts as an effective barrier against toxic compounds, and therefore compromising this structure could increase sensitivity to currently available antibiotics. In this study, we show that the Mla pathway, a system involved in maintaining the integrity of the outer membrane, is genetically and functionally different in Burkholderia cepacia complex species compared to that in other proteobacteria. Mutants in mla genes of Burkholderia cenocepacia or Burkholderia dolosa were sensitive to Gram-positive antibiotics, while this effect was not observed in Escherichia coli or Pseudomonas aeruginosa The Mla pathway in Burkholderia species may represent an ideal genus-specific target to address their intrinsic antimicrobial resistances.
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Targeting the Nonmevalonate Pathway in Burkholderia cenocepacia Increases Susceptibility to Certain β-Lactam Antibiotics. Antimicrob Agents Chemother 2018; 62:AAC.02607-17. [PMID: 29439968 DOI: 10.1128/aac.02607-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/07/2018] [Indexed: 11/20/2022] Open
Abstract
The nonmevalonate pathway is the sole pathway for isoprenoid biosynthesis in Burkholderia cenocepacia and is possibly a novel target for the development of antibacterial chemotherapy. The goals of the present study were to evaluate the essentiality of dxr, the second gene of the nonmevalonate pathway, in B. cenocepacia and to determine whether interfering with the nonmevalonate pathway increases susceptibility toward antibiotics. To this end, a rhamnose-inducible conditional dxr knockdown mutant of B. cenocepacia strain K56-2 (B. cenocepacia K56-2dxr) was constructed, using a plasmid which enables the delivery of a rhamnose-inducible promoter in the chromosome. Expression of dxr is essential for bacterial growth; the growth defect observed in the dxr mutant could be complemented by expressing dxr in trans under the control of a constitutive promoter, but not by providing 2-C-methyl-d-erythritol-4-phosphate, the reaction product of DXR (1-deoxy-d-xylulose 5-phosphate reductoisomerase). B. cenocepacia K56-2dxr showed markedly increased susceptibility to the β-lactam antibiotics aztreonam, ceftazidime, and cefotaxime, while susceptibility to other antibiotics was not (or was much less) affected; this increased susceptibility could also be complemented by in trans expression of dxr A similarly increased susceptibility was observed when antibiotics were combined with FR900098, a known DXR inhibitor. Our data confirm that the nonmevalonate pathway is essential in B. cenocepacia and suggest that combining potent DXR inhibitors with selected β-lactam antibiotics is a useful strategy to combat B. cenocepacia infections.
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Successful Treatment of Persistent Burkholderia cepacia Complex Bacteremia with Ceftazidime-Avibactam. Antimicrob Agents Chemother 2018; 62:62/4/e02213-17. [PMID: 29588357 DOI: 10.1128/aac.02213-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We report our clinical experience treating a 2-month-old infant with congenital diaphragmatic hernia who experienced prolonged bacteremia with Burkholderia cepacia complex (Bcc) despite conventional antibiotic therapy and appropriate source control measures. The infection resolved after initiation of ceftazidime-avibactam. Whole-genome sequencing revealed that the isolate most closely resembled B. contaminans and identified the mechanism of resistance that likely contributed to clinical cure with this agent. Ceftazidime-avibactam should be considered salvage therapy for Bcc infections if other treatment options have been exhausted.
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Bakthavatchalam YD, Pragasam AK, Biswas I, Veeraraghavan B. Polymyxin susceptibility testing, interpretative breakpoints and resistance mechanisms: An update. J Glob Antimicrob Resist 2018; 12:124-136. [DOI: 10.1016/j.jgar.2017.09.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/25/2017] [Accepted: 09/19/2017] [Indexed: 12/12/2022] Open
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Yokota SI, Hakamada H, Yamamoto S, Sato T, Shiraishi T, Shinagawa M, Takahashi S. Release of large amounts of lipopolysaccharides from Pseudomonas aeruginosa cells reduces their susceptibility to colistin. Int J Antimicrob Agents 2018; 51:888-896. [PMID: 29432867 DOI: 10.1016/j.ijantimicag.2018.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/10/2018] [Accepted: 02/03/2018] [Indexed: 10/18/2022]
Abstract
Pseudomonas aeruginosa is an important etiological agent of opportunistic infections. Injectable colistin is available as a last-line treatment option for multidrug-resistant P. aeruginosa infections. When cells were inoculated at a high number, colistin-susceptible P. aeruginosa grew on agar medium containing colistin at a concentration 10-fold higher than the minimum inhibitory concentration without acquiring colistin resistance. This study examined the responsible mechanism for growth in the presence of a high concentration of colistin. Cell wash fluid derived from P. aeruginosa efficiently reduced colistin antimicrobial activity. This reduction was mediated by lipopolysaccharide (LPS) in the wash fluid. Extracellular LPS inhibited colistin activity more effectively than cell-bound LPS in fixed cells. Cell wash fluids from Escherichia coli and Acinetobacter baumannii also reduced colistin activity; however, they were less potent than those from P. aeruginosa. The amount of LPS in cell wash fluid from P. aeruginosa was approximately 10-fold higher than that in fluid from E. coli or A. baumannii. In conclusion, cell-free LPS derived from bacterial cells inhibited the antimicrobial activity of colistin, and this effect was greatest for P. aeruginosa. Thus, large amounts of broken and dead cells of P. aeruginosa at infection foci will reduce the effectiveness of colistin, even against cells that have not yet acquired resistance.
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Affiliation(s)
- Shin-Ichi Yokota
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan.
| | - Hiroshi Hakamada
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Soh Yamamoto
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Toyotaka Sato
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Tsukasa Shiraishi
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Masaaki Shinagawa
- Division of Laboratory Medicine, Sapporo Medical University Hospital, Sapporo, Japan
| | - Satoshi Takahashi
- Division of Laboratory Medicine, Sapporo Medical University Hospital, Sapporo, Japan; Department of Infection Control and Laboratory Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
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The Essential Genome of Burkholderia cenocepacia H111. J Bacteriol 2017; 199:JB.00260-17. [PMID: 28847919 DOI: 10.1128/jb.00260-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 08/19/2017] [Indexed: 12/31/2022] Open
Abstract
The study of the minimum set of genes required to sustain life is a fundamental question in biological research. Recent studies on bacterial essential genes suggested that between 350 and 700 genes are essential to support autonomous bacterial cell growth. Essential genes are of interest as potential new antimicrobial drug targets; hence, our aim was to identify the essential genome of the cystic fibrosis (CF) isolate Burkholderia cenocepacia H111. Using a transposon sequencing (Tn-Seq) approach, we identified essential genes required for growth in rich medium under aerobic and microoxic conditions as well as in a defined minimal medium with citrate as a sole carbon source. Our analysis suggests that 398 genes are required for autonomous growth in rich medium, a number that represents only around 5% of the predicted genes of this bacterium. Five hundred twenty-six genes were required to support growth in minimal medium, and 434 genes were essential under microoxic conditions (0.5% O2). A comparison of these data sets identified 339 genes that represent the minimal set of essential genes required for growth under all conditions tested and can be considered the core essential genome of B. cenocepacia H111. The majority of essential genes were found to be located on chromosome 1, and few such genes were located on chromosome 2, where most of them were clustered in one region. This gene cluster is fully conserved in all Burkholderia species but is present on chromosome 1 in members of the closely related genus Ralstonia, suggesting that the transfer of these essential genes to chromosome 2 in a common ancestor contributed toward the separation of the two genera.IMPORTANCE Transposon sequencing (Tn-Seq) is a powerful method used to identify genes that are essential for autonomous growth under various conditions. In this study, we have identified a set of "core essential genes" that are required for growth under multiple conditions, and these genes represent potential antimicrobial targets. We also identified genes specifically required for growth under low-oxygen and nutrient-limited environments. We generated conditional mutants to verify the results of our Tn-Seq analysis and demonstrate that one of the identified genes was not essential per se but was an artifact of the construction of the mutant library. We also present verified examples of genes that were not truly essential but, when inactivated, showed a growth defect. These examples have identified so-far-underestimated shortcomings of this powerful method.
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Scoffone VC, Chiarelli LR, Trespidi G, Mentasti M, Riccardi G, Buroni S. Burkholderia cenocepacia Infections in Cystic Fibrosis Patients: Drug Resistance and Therapeutic Approaches. Front Microbiol 2017; 8:1592. [PMID: 28878751 PMCID: PMC5572248 DOI: 10.3389/fmicb.2017.01592] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/04/2017] [Indexed: 12/29/2022] Open
Abstract
Burkholderia cenocepacia is an opportunistic pathogen particularly dangerous for cystic fibrosis (CF) patients. It can cause a severe decline in CF lung function possibly developing into a life-threatening systemic infection known as cepacia syndrome. Antibiotic resistance and presence of numerous virulence determinants in the genome make B. cenocepacia extremely difficult to treat. Better understanding of its resistance profiles and mechanisms is crucial to improve management of these infections. Here, we present the clinical distribution of B. cenocepacia described in the last 6 years and methods for identification and classification of epidemic strains. We also detail new antibiotics, clinical trials, and alternative approaches reported in the literature in the last 5 years to tackle B. cenocepacia resistance issue. All together these findings point out the urgent need of new and alternative therapies to improve CF patients’ life expectancy.
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Affiliation(s)
- Viola C Scoffone
- Department of Biology and Biotechnology, University of PaviaPavia, Italy
| | | | - Gabriele Trespidi
- Department of Biology and Biotechnology, University of PaviaPavia, Italy
| | - Massimo Mentasti
- Respiratory and Vaccine Preventable Bacteria Reference Unit, Public Health EnglandLondon, United Kingdom.,Department of Microbiology, Royal Cornwall HospitalTruro, United Kingdom
| | - Giovanna Riccardi
- Department of Biology and Biotechnology, University of PaviaPavia, Italy
| | - Silvia Buroni
- Department of Biology and Biotechnology, University of PaviaPavia, Italy
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Relationships Between Resistance and Virulence in Burkholderia pseudomallei. CURRENT TROPICAL MEDICINE REPORTS 2017. [DOI: 10.1007/s40475-017-0119-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dingjan T, Imberty A, Pérez S, Yuriev E, Ramsland PA. Molecular Simulations of Carbohydrates with a Fucose-Binding Burkholderia ambifaria Lectin Suggest Modulation by Surface Residues Outside the Fucose-Binding Pocket. Front Pharmacol 2017; 8:393. [PMID: 28680402 PMCID: PMC5478714 DOI: 10.3389/fphar.2017.00393] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 06/06/2017] [Indexed: 12/22/2022] Open
Abstract
Burkholderia ambifaria is an opportunistic respiratory pathogen belonging to the Burkholderia cepacia complex, a collection of species responsible for the rapidly fatal cepacia syndrome in cystic fibrosis patients. A fucose-binding lectin identified in the B. ambifaria genome, BambL, is able to adhere to lung tissue, and may play a role in respiratory infection. X-ray crystallography has revealed the bound complex structures for four fucosylated human blood group epitopes (blood group B, H type 1, H type 2, and Lex determinants). The present study employed computational approaches, including docking and molecular dynamics (MD), to extend the structural analysis of BambL-oligosaccharide complexes to include four additional blood group saccharides (A, Lea, Leb, and Ley) and a library of blood-group-related carbohydrates. Carbohydrate recognition is dominated by interactions with fucose via a hydrogen-bonding network involving Arg15, Glu26, Ala38, and Trp79 and a stacking interaction with Trp74. Additional hydrogen bonds to non-fucose residues are formed with Asp30, Tyr35, Thr36, and Trp74. BambL recognition is dominated by interactions with fucose, but also features interactions with other parts of the ligands that may modulate specificity or affinity. The detailed computational characterization of the BambL carbohydrate-binding site provides guidelines for the future design of lectin inhibitors.
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Affiliation(s)
- Tamir Dingjan
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash UniversityMelbourne, VIC, Australia
| | - Anne Imberty
- Centre de Recherches sur les Macromolécules Végétales, Centre National de la Recherche Scientifique UPR5301, Université Grenoble AlpesGrenoble, France
| | - Serge Pérez
- Département de Pharmacochimie Moléculaire, Centre National de la Recherche Scientifique, UMR5063, Université Grenoble AlpesGrenoble, France
| | - Elizabeth Yuriev
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash UniversityMelbourne, VIC, Australia
| | - Paul A Ramsland
- School of Science, RMIT UniversityMelbourne, VIC, Australia.,Department of Surgery Austin Health, University of MelbourneMelbourne, VIC, Australia.,Department of Immunology, Central Clinical School, Monash UniversityMelbourne, VIC, Australia.,Burnet InstituteMelbourne, VIC, Australia
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Iida M, Yamada K, Nango Y, Yamaguchi Y, Ogita A, Fujita KI, Tanaka T. Vacuolar H+-ATPase subunit Vma1p functions as the molecular ligand in the vacuole-targeting fungicidal activity of polymyxin B. Microbiology (Reading) 2017; 163:531-540. [DOI: 10.1099/mic.0.000450] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Maki Iida
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Keiichi Yamada
- Department of Chemistry and Chemical Biology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Yoshiya Nango
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Yoshihiro Yamaguchi
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Akira Ogita
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Research Center for Urban Health and Sports, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Ken-ichi Fujita
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Toshio Tanaka
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
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Respiratory Microbiome of Endangered Southern Resident Killer Whales and Microbiota of Surrounding Sea Surface Microlayer in the Eastern North Pacific. Sci Rep 2017; 7:394. [PMID: 28341851 PMCID: PMC5428453 DOI: 10.1038/s41598-017-00457-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/27/2017] [Indexed: 01/01/2023] Open
Abstract
In the Salish Sea, the endangered Southern Resident Killer Whale (SRKW) is a high trophic indicator of ecosystem health. Three major threats have been identified for this population: reduced prey availability, anthropogenic contaminants, and marine vessel disturbances. These perturbations can culminate in significant morbidity and mortality, usually associated with secondary infections that have a predilection to the respiratory system. To characterize the composition of the respiratory microbiota and identify recognized pathogens of SRKW, exhaled breath samples were collected between 2006–2009 and analyzed for bacteria, fungi and viruses using (1) culture-dependent, targeted PCR-based methodologies and (2) taxonomically broad, non-culture dependent PCR-based methodologies. Results were compared with sea surface microlayer (SML) samples to characterize the respective microbial constituents. An array of bacteria and fungi in breath and SML samples were identified, as well as microorganisms that exhibited resistance to multiple antimicrobial agents. The SML microbes and respiratory microbiota carry a pathogenic risk which we propose as an additional, fourth putative stressor (pathogens), which may adversely impact the endangered SRKW population.
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Abstract
Antimicrobial peptides (AMPs), also known as host defense peptides, are small naturally occurring microbicidal molecules produced by the host innate immune response that function as a first line of defense to kill pathogenic microorganisms by inducing deleterious cell membrane damage. AMPs also possess signaling and chemoattractant activities and can modulate the innate immune response to enhance protective immunity or suppress inflammation. Human pathogens have evolved defense molecules and strategies to counter and survive the AMPs released by host immune cells such as neutrophils and macrophages. Here, we review the various mechanisms used by human bacterial pathogens to resist AMP-mediated killing, including surface charge modification, active efflux, alteration of membrane fluidity, inactivation by proteolytic digestion, and entrapment by surface proteins and polysaccharides. Enhanced understanding of AMP resistance at the molecular level may offer insight into the mechanisms of bacterial pathogenesis and augment the discovery of novel therapeutic targets and drug design for the treatment of recalcitrant multidrug-resistant bacterial infections.
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Trimble MJ, Mlynárčik P, Kolář M, Hancock REW. Polymyxin: Alternative Mechanisms of Action and Resistance. Cold Spring Harb Perspect Med 2016; 6:cshperspect.a025288. [PMID: 27503996 DOI: 10.1101/cshperspect.a025288] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antibiotic resistance among pathogenic bacteria is an ever-increasing issue worldwide. Unfortunately, very little has been achieved in the pharmaceutical industry to combat this problem. This has led researchers and the medical field to revisit past drugs that were deemed too toxic for clinical use. In particular, the cyclic cationic peptides polymyxin B and colistin, which are specific for Gram-negative bacteria, have been used as "last resort" antimicrobials. Before the 1980s, these drugs were known for their renal and neural toxicities; however, new clinical practices and possibly improved manufacturing have made them safer to use. Previously suggested to primarily attack the membranes of Gram-negative bacteria and to not easily select for resistant mutants, recent research exploring resistance and mechanisms of action has provided new perspectives. This review focuses primarily on the proposed alternative mechanisms of action, known resistance mechanisms, and how these support the alternative mechanisms of action.
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Affiliation(s)
- Michael J Trimble
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Patrik Mlynárčik
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University, 771 47 Olomouc, Czech Republic
| | - Milan Kolář
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University, 771 47 Olomouc, Czech Republic
| | - Robert E W Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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40
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Wong YC, Abd El Ghany M, Naeem R, Lee KW, Tan YC, Pain A, Nathan S. Candidate Essential Genes in Burkholderia cenocepacia J2315 Identified by Genome-Wide TraDIS. Front Microbiol 2016; 7:1288. [PMID: 27597847 PMCID: PMC4993015 DOI: 10.3389/fmicb.2016.01288] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/04/2016] [Indexed: 12/13/2022] Open
Abstract
Burkholderia cenocepacia infection often leads to fatal cepacia syndrome in cystic fibrosis patients. However, antibiotic therapy rarely results in complete eradication of the pathogen due to its intrinsic resistance to many clinically available antibiotics. Recent attention has turned to the identification of essential genes as the proteins encoded by these genes may serve as potential targets for development of novel antimicrobials. In this study, we utilized TraDIS (Transposon Directed Insertion-site Sequencing) as a genome-wide screening tool to facilitate the identification of B. cenocepacia genes essential for its growth and viability. A transposon mutant pool consisting of approximately 500,000 mutants was successfully constructed, with more than 400,000 unique transposon insertion sites identified by computational analysis of TraDIS datasets. The saturated library allowed for the identification of 383 genes that were predicted to be essential in B. cenocepacia. We extended the application of TraDIS to identify conditionally essential genes required for in vitro growth and revealed an additional repertoire of 439 genes to be crucial for B. cenocepacia growth under nutrient-depleted conditions. The library of B. cenocepacia mutants can subsequently be subjected to various biologically related conditions to facilitate the discovery of genes involved in niche adaptation as well as pathogenicity and virulence.
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Affiliation(s)
- Yee-Chin Wong
- Faculty of Science and Technology, School of Biosciences and Biotechnology, Universiti Kebangsaan Malaysia Bangi, Malaysia
| | - Moataz Abd El Ghany
- Chemical and Life Sciences and Engineering Division, King Abdullah University of Science and TechnologyThuwal, Saudi Arabia; The Westmead Institute for Medical Research and The Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, SydneyNSW, Australia
| | - Raeece Naeem
- Chemical and Life Sciences and Engineering Division, King Abdullah University of Science and Technology Thuwal, Saudi Arabia
| | | | | | - Arnab Pain
- Chemical and Life Sciences and Engineering Division, King Abdullah University of Science and Technology Thuwal, Saudi Arabia
| | - Sheila Nathan
- Faculty of Science and Technology, School of Biosciences and Biotechnology, Universiti Kebangsaan Malaysia Bangi, Malaysia
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Abstract
The genus Burkholderia comprises metabolically diverse and adaptable Gram-negative bacteria, which thrive in often adversarial environments. A few members of the genus are prominent opportunistic pathogens. These include Burkholderia mallei and Burkholderia pseudomallei of the B. pseudomallei complex, which cause glanders and melioidosis, respectively. Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia vietnamiensis belong to the Burkholderia cepacia complex and affect mostly cystic fibrosis patients. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. The first line of defense against antimicrobials in Burkholderia species is the outer membrane penetration barrier. Most Burkholderia contain a modified lipopolysaccharide that causes intrinsic polymyxin resistance. Contributing to reduced drug penetration are restrictive porin proteins. Efflux pumps of the resistance nodulation cell division family are major players in Burkholderia multidrug resistance. Third and fourth generation β-lactam antibiotics are seminal for treatment of Burkholderia infections, but therapeutic efficacy is compromised by expression of several β-lactamases and ceftazidime target mutations. Altered DNA gyrase and dihydrofolate reductase targets cause fluoroquinolone and trimethoprim resistance, respectively. Although antibiotic resistance hampers therapy of Burkholderia infections, the characterization of resistance mechanisms lags behind other non-enteric Gram-negative pathogens, especially ESKAPE bacteria such as Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa.
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Affiliation(s)
- Katherine A Rhodes
- Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute and Institute for Therapeutic Innovation, University of Florida, Gainesville, FL, USA; Department of Microbiology Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Herbert P Schweizer
- Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute and Institute for Therapeutic Innovation, University of Florida, Gainesville, FL, USA.
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150292. [PMID: 27160595 PMCID: PMC4874390 DOI: 10.1098/rstb.2015.0292] [Citation(s) in RCA: 205] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2016] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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43
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016. [PMID: 27160595 DOI: 10.1098/rstb.2015.0292.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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Abstract
Cationic antimicrobial peptides (CAMPs) are important innate immune defenses that inhibit colonization by pathogens and contribute to clearance of infections. Gram-negative bacterial pathogens are a major target, yet many of them have evolved mechanisms to resist these antimicrobials. These resistance mechanisms can be critical contributors to bacterial virulence and are often crucial for survival within the host. Here, we summarize methods used by Gram-negative bacteria to resist CAMPs. Understanding these mechanisms may lead to new therapeutic strategies against pathogens with extensive CAMP resistance.
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Affiliation(s)
- Victor I. Band
- Department of Microbiology and Immunology, Emory University, Atlanta, GA 30329, USA; E-Mail:
- Yerkes Primate Research Center, Emory University, Atlanta, GA 30329, USA
- Emory Vaccine Center, Emory University, Atlanta, GA 30329, USA
| | - David S. Weiss
- Yerkes Primate Research Center, Emory University, Atlanta, GA 30329, USA
- Emory Vaccine Center, Emory University, Atlanta, GA 30329, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30329, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-404-727-8214; Fax: +1-404-727-8199
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de la Fuente-Núñez C, Mansour SC, Wang Z, Jiang L, Breidenstein EB, Elliott M, Reffuveille F, Speert DP, Reckseidler-Zenteno SL, Shen Y, Haapasalo M, Hancock RE. Anti-Biofilm and Immunomodulatory Activities of Peptides That Inhibit Biofilms Formed by Pathogens Isolated from Cystic Fibrosis Patients. Antibiotics (Basel) 2016. [PMID: 26221537 PMCID: PMC4515429 DOI: 10.3390/antibiotics3040509] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Cystic fibrosis (CF) patients often acquire chronic respiratory tract infections due to Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc) species. In the CF lung, these bacteria grow as multicellular aggregates termed biofilms. Biofilms demonstrate increased (adaptive) resistance to conventional antibiotics, and there are currently no available biofilm-specific therapies. Using plastic adherent, hydroxyapatite and flow cell biofilm models coupled with confocal and scanning electron microscopy, it was demonstrated that an anti-biofilm peptide 1018 prevented biofilm formation, eradicated mature biofilms and killed biofilms formed by a wide range of P. aeruginosa and B. cenocepacia clinical isolates. New peptide derivatives were designed that, compared to their parent peptide 1018, showed similar or decreased anti-biofilm activity against P. aeruginosa biofilms, but increased activity against biofilms formed by the Gram-positive bacterium methicillin resistant Staphylococcus aureus. In addition, some of these new peptide derivatives retained the immunomodulatory activity of 1018 since they induced the production of the chemokine monocyte chemotactic protein-1 (MCP-1) and suppressed lipopolysaccharide-mediated tumor necrosis factor-α (TNF-α) production by human peripheral blood mononuclear cells (PBMC) and were non-toxic towards these cells. Peptide 1018 and its derivatives provide promising leads for the treatment of chronic biofilm infections and hyperinflammatory lung disease in CF patients.
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Affiliation(s)
- César de la Fuente-Núñez
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; E-Mails: (C.D.L.F.-N.); (S.C.M.); (L.J.); (E.B.M.B.); (M.E.); (F.R.)
| | - Sarah C. Mansour
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; E-Mails: (C.D.L.F.-N.); (S.C.M.); (L.J.); (E.B.M.B.); (M.E.); (F.R.)
| | - Zhejun Wang
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada; E-Mails: (Z.W.); (Y.S.); (M.H.)
| | - Lucy Jiang
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; E-Mails: (C.D.L.F.-N.); (S.C.M.); (L.J.); (E.B.M.B.); (M.E.); (F.R.)
| | - Elena B.M. Breidenstein
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; E-Mails: (C.D.L.F.-N.); (S.C.M.); (L.J.); (E.B.M.B.); (M.E.); (F.R.)
| | - Melissa Elliott
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; E-Mails: (C.D.L.F.-N.); (S.C.M.); (L.J.); (E.B.M.B.); (M.E.); (F.R.)
| | - Fany Reffuveille
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; E-Mails: (C.D.L.F.-N.); (S.C.M.); (L.J.); (E.B.M.B.); (M.E.); (F.R.)
| | - David P. Speert
- Department of Pediatrics, University of British Columbia, Vancouver, BC, V6H 3V4, Canada; E-Mail:
| | | | - Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada; E-Mails: (Z.W.); (Y.S.); (M.H.)
| | - Markus Haapasalo
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada; E-Mails: (Z.W.); (Y.S.); (M.H.)
| | - Robert E.W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; E-Mails: (C.D.L.F.-N.); (S.C.M.); (L.J.); (E.B.M.B.); (M.E.); (F.R.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel: +1-604-822-2682; Fax: +1-604-827-5566
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Functional Genome Screening to Elucidate the Colistin Resistance Mechanism. Sci Rep 2016; 6:23156. [PMID: 26988670 PMCID: PMC4796810 DOI: 10.1038/srep23156] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/25/2016] [Indexed: 12/17/2022] Open
Abstract
Antibiogram profile of 1590 clinical bacterial isolates based on thirteen different antimicrobial compounds showed that 1.6% of the bacterial isolates are multidrug resistant. Distribution pattern based on 16S rRNA sequence analysis showed that Pseudomonas aeruginosa constituted the largest group (83.6%) followed by Burkholderia pseudomallei sp. A191 (5.17%), Staphylococcus sp. A261 (3.45%). Among the various antibiotics used, colistin appeared to be the most effective against the Gram negative bacteria. Burkholderia pseudomallei sp. A191 and Pseudomonas aeruginosa sp. A111 showed resistance to 1500 μg/ml and 750 μg/ml of colistin respectively which constitutes 7.7% of the bacterial population. A functional genomics strategy was employed to discover the molecular support for colistin resistance in Burkholderia pseudomallei sp. A191. A pUC plasmid-based genomic expression library was constructed with an estimated library size of 2.1 × 107bp. Five colistin resistant clones were obtained after functional screening of the library. Analysis of DNA sequence of five colistin resistant clones showed homology to two component regularity systems (TCRS) encoding for a histidine kinase (mrgS) and its regulatory component (mrgR). Cross complementation assay showed that mutations in mrgS were sufficient enough to confer colistin resistant phenotype in a sensitive strain.
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Using adjuvants and environmental factors to modulate the activity of antimicrobial peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:926-35. [PMID: 26751595 DOI: 10.1016/j.bbamem.2015.12.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 12/22/2015] [Accepted: 12/29/2015] [Indexed: 12/12/2022]
Abstract
The increase in antibiotic resistant and multi-drug resistant bacterial infections has serious implications for the future of health care. The difficulty in finding both new microbial targets and new drugs against existing targets adds to the concern. The use of combination and adjuvant therapies are potential strategies to counter this threat. Antimicrobial peptides (AMPs) are a promising class of antibiotics (ABs), particularly for topical and surface applications. Efforts have been directed toward a number of strategies, including the use of conventional ABs combined with AMPs, and the use of potentiating agents to increase the performance of AMPs. This review focuses on combination strategies such as adjuvants and the manipulation of environmental variables to improve the efficacy of AMPs as potential therapeutic agents. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert.
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Loutet SA, El-Halfawy OM, Jassem AN, López JMS, Medarde AF, Speert DP, Davies JE, Valvano MA. Identification of synergists that potentiate the action of polymyxin B against Burkholderia cenocepacia. Int J Antimicrob Agents 2015; 46:376-80. [PMID: 26187366 DOI: 10.1016/j.ijantimicag.2015.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/19/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
Abstract
Burkholderia cenocepacia and other members of the Burkholderia cepacia complex (BCC) are highly multidrug-resistant bacteria that cause severe pulmonary infections in patients with cystic fibrosis. A screen of 2686 compounds derived from marine organisms identified molecules that could synergise with polymyxin B (PMB) to inhibit the growth of B. cenocepacia. At 1 μg/mL, five compounds synergised with PMB and inhibited the growth of B. cenocepacia by ≥70% compared with growth in PMB alone. Follow-up testing revealed that one compound from the screen, the aminocoumarin antibiotic novobiocin, synergised with PMB and colistin against tobramycin-resistant clinical isolates of B. cenocepacia and Burkholderia multivorans. In parallel, we show that novobiocin sensitivity is common among BCC species and that these bacteria are even more susceptible to an alternative aminocoumarin, clorobiocin, which also had an additive effect with PMB against B. cenocepacia. These studies support using aminocoumarin antibiotics to treat BCC infections and show that synergisers can be found to increase the efficacy of antimicrobial peptides and polymyxins against BCC bacteria.
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Affiliation(s)
- Slade A Loutet
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada; Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Omar M El-Halfawy
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada; Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Agatha N Jassem
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | | | | | - David P Speert
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada; Department of Pathology, University of British Columbia, Vancouver, BC, Canada
| | - Julian E Davies
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Miguel A Valvano
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada; Centre for Infection and Immunity, Queen's University Belfast, Belfast, UK.
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Kim JK, Son DW, Kim CH, Cho JH, Marchetti R, Silipo A, Sturiale L, Park HY, Huh YR, Nakayama H, Fukatsu T, Molinaro A, Lee BL. Insect Gut Symbiont Susceptibility to Host Antimicrobial Peptides Caused by Alteration of the Bacterial Cell Envelope. J Biol Chem 2015; 290:21042-21053. [PMID: 26116716 DOI: 10.1074/jbc.m115.651158] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Indexed: 01/05/2023] Open
Abstract
The molecular characterization of symbionts is pivotal for understanding the cross-talk between symbionts and hosts. In addition to valuable knowledge obtained from symbiont genomic studies, the biochemical characterization of symbionts is important to fully understand symbiotic interactions. The bean bug (Riptortus pedestris) has been recognized as a useful experimental insect gut symbiosis model system because of its cultivatable Burkholderia symbionts. This system is greatly advantageous because it allows the acquisition of a large quantity of homogeneous symbionts from the host midgut. Using these naïve gut symbionts, it is possible to directly compare in vivo symbiotic cells with in vitro cultured cells using biochemical approaches. With the goal of understanding molecular changes that occur in Burkholderia cells as they adapt to the Riptortus gut environment, we first elucidated that symbiotic Burkholderia cells are highly susceptible to purified Riptortus antimicrobial peptides. In search of the mechanisms of the increased immunosusceptibility of symbionts, we found striking differences in cell envelope structures between cultured and symbiotic Burkholderia cells. The bacterial lipopolysaccharide O antigen was absent from symbiotic cells examined by gel electrophoretic and mass spectrometric analyses, and their membranes were more sensitive to detergent lysis. These changes in the cell envelope were responsible for the increased susceptibility of the Burkholderia symbionts to host innate immunity. Our results suggest that the symbiotic interactions between the Riptortus host and Burkholderia gut symbionts induce bacterial cell envelope changes to achieve successful gut symbiosis.
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Affiliation(s)
- Jiyeun Kate Kim
- Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan 609-735, South Korea
| | - Dae Woo Son
- Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan 609-735, South Korea
| | - Chan-Hee Kim
- Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan 609-735, South Korea
| | - Jae Hyun Cho
- Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan 609-735, South Korea
| | - Roberta Marchetti
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, Napoli 80126, Italy
| | - Alba Silipo
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, Napoli 80126, Italy
| | - Luisa Sturiale
- CNR-Istituto per i Polimeri, Compositi e Biomateriali IPCB, Via P. Gaifami 18, Catania 95126, Italy
| | - Ha Young Park
- Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan 609-735, South Korea
| | - Ye Rang Huh
- Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan 609-735, South Korea
| | - Hiroshi Nakayama
- Biomolecular Characterization Team, RIKEN Advanced Science Institute, Saitama 351-0198, Japan
| | - Takema Fukatsu
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8566, Japan
| | - Antonio Molinaro
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, Napoli 80126, Italy
| | - Bok Luel Lee
- Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan 609-735, South Korea.
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Burkholderia cenocepacia Lipopolysaccharide Modification and Flagellin Glycosylation Affect Virulence but Not Innate Immune Recognition in Plants. mBio 2015; 6:e00679. [PMID: 26045541 PMCID: PMC4462625 DOI: 10.1128/mbio.00679-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
UNLABELLED Burkholderia cenocepacia causes opportunistic infections in plants, insects, animals, and humans, suggesting that "virulence" depends on the host and its innate susceptibility to infection. We hypothesized that modifications in key bacterial molecules recognized by the innate immune system modulate host responses to B. cenocepacia. Indeed, modification of lipopolysaccharide (LPS) with 4-amino-4-deoxy-L-arabinose and flagellin glycosylation attenuates B. cenocepacia infection in Arabidopsis thaliana and Galleria mellonella insect larvae. However, B. cenocepacia LPS and flagellin triggered rapid bursts of nitric oxide and reactive oxygen species in A. thaliana leading to activation of the PR-1 defense gene. These responses were drastically reduced in plants with fls2 (flagellin FLS2 host receptor kinase), Atnoa1 (nitric oxide-associated protein 1), and dnd1-1 (reduced production of nitric oxide) null mutations. Together, our results indicate that LPS modification and flagellin glycosylation do not affect recognition by plant receptors but are required for bacteria to establish overt infection. IMPORTANCE Virulence and pathogenicity are properties ascribed to microbes, which actually require careful consideration of the host. Using the term "pathogen" to define a microbe without considering its host has recently been debated, since the microbe's capacity to establish a niche in a given host is a critical feature associated with infection. Opportunistic bacteria are a perfect example of microbes whose ability to cause disease is intimately related to the host's ability to recognize and respond to the infection. Here, we use the opportunistic bacterium Burkholderia cenocepacia and the host plant Arabidopsis thaliana to investigate the role of bacterial surface molecules, namely, lipopolysaccharide and flagellin, in contributing to infection and also in eliciting a host response. We reveal that both molecules can be modified by glycosylation, and although the modifications are critical for the bacteria to establish an infection, they do not impact the host's ability to recognize the pathogen.
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