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Laborda P, Molin S, Johansen HK, Martínez JL, Hernando-Amado S. Role of bacterial multidrug efflux pumps during infection. World J Microbiol Biotechnol 2024; 40:226. [PMID: 38822187 DOI: 10.1007/s11274-024-04042-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 05/29/2024] [Indexed: 06/02/2024]
Abstract
Multidrug efflux pumps are protein complexes located in the cell envelope that enable bacteria to expel, not only antibiotics, but also a wide array of molecules relevant for infection. Hence, they are important players in microbial pathogenesis. On the one hand, efflux pumps can extrude exogenous compounds, including host-produced antimicrobial molecules. Through this extrusion, pathogens can resist antimicrobial agents and evade host defenses. On the other hand, efflux pumps also have a role in the extrusion of endogenous compounds, such as bacterial intercommunication signaling molecules, virulence factors or metabolites. Therefore, efflux pumps are involved in the modulation of bacterial behavior and virulence, as well as in the maintenance of the bacterial homeostasis under different stresses found within the host. This review delves into the multifaceted roles that efflux pumps have, shedding light on their impact on bacterial virulence and their contribution to bacterial infection. These observations suggest that strategies targeting bacterial efflux pumps could both reinvigorate the efficacy of existing antibiotics and modulate the bacterial pathogenicity to the host. Thus, a comprehensive understanding of bacterial efflux pumps can be pivotal for the development of new effective strategies for the management of infectious diseases.
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Affiliation(s)
- Pablo Laborda
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, 9301, Denmark.
| | - Søren Molin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Helle Krogh Johansen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, 9301, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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Elbediwi M, Rolff J. Metabolic pathways and antimicrobial peptide resistance in bacteria. J Antimicrob Chemother 2024:dkae128. [PMID: 38742645 DOI: 10.1093/jac/dkae128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024] Open
Abstract
Antimicrobial resistance is a pressing concern that poses a significant threat to global public health, necessitating the exploration of alternative strategies to combat drug-resistant microbial infections. Recently, antimicrobial peptides (AMPs) have gained substantial attention as possible replacements for conventional antibiotics. Because of their pharmacodynamics and killing mechanisms, AMPs display a lower risk of bacterial resistance evolution compared with most conventional antibiotics. However, bacteria display different mechanisms to resist AMPs, and the role of metabolic pathways in the resistance mechanism is not fully understood. This review examines the intricate relationship between metabolic genes and AMP resistance, focusing on the impact of metabolic pathways on various aspects of resistance. Metabolic pathways related to guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp) [collectively (p)ppGpp], the tricarboxylic acid (TCA) cycle, haem biosynthesis, purine and pyrimidine biosynthesis, and amino acid and lipid metabolism influence in different ways metabolic adjustments, biofilm formation and energy production that could be involved in AMP resistance. By targeting metabolic pathways and their associated genes, it could be possible to enhance the efficacy of existing antimicrobial therapies and overcome the challenges exhibited by phenotypic (recalcitrance) and genetic resistance toward AMPs. Further research in this area is needed to provide valuable insights into specific mechanisms, uncover novel therapeutic targets, and aid in the fight against antimicrobial resistance.
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Affiliation(s)
- Mohammed Elbediwi
- Evolutionary Biology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
- Animal Health Research Institute, Agriculture Research Centre, 12618 Cairo, Egypt
| | - Jens Rolff
- Evolutionary Biology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
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3
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Rice J, Gibson J, Young E, Souder K, Cunningham K, Schmitt DM. Low Oxygen Concentration Reduces Neisseria gonorrhoeae Susceptibility to Resazurin. Antibiotics (Basel) 2024; 13:395. [PMID: 38786124 PMCID: PMC11117329 DOI: 10.3390/antibiotics13050395] [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: 03/08/2024] [Revised: 04/18/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
Neisseria gonorrhoeae has developed resistance to every antibiotic currently approved for the treatment of gonorrhea, prompting the development of new therapies. The phenoxazine dye resazurin exhibits robust antimicrobial activity against N. gonorrhoeae in vitro but fails to limit vaginal colonization by N. gonorrhoeae in a mouse model. The lack of in vivo efficacy may be due to oxygen limitation as in vitro susceptibility assays with resazurin are conducted under atmospheric oxygen while a microaerophilic environment is present in the vagina. Here, we utilized broth microdilution assays to determine the susceptibility of N. gonorrhoeae to resazurin under low and atmospheric oxygen conditions. The minimal inhibitory concentration of resazurin for multiple N. gonorrhoeae clinical isolates was significantly higher under low oxygen. This effect was specific to resazurin as N. gonorrhoeae was equally susceptible to other antibiotics under low and atmospheric oxygen conditions. The reduced susceptibility of N. gonorrhoeae to resazurin under low oxygen was largely attributed to reduced oxidative stress, as the addition of antioxidants under atmospheric oxygen mimicked the reduced susceptibility to resazurin observed under low oxygen. Together, these data suggest oxygen concentration is an important factor to consider when evaluating the efficacy of new antibiotics against N. gonorrhoeae in vitro.
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Affiliation(s)
| | | | | | | | | | - Deanna M. Schmitt
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV 26074, USA
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Ostan NKH, Cole GB, Wang FZ, Reichheld SE, Moore G, Pan C, Yu R, Lai CCL, Sharpe S, Lee HO, Schryvers AB, Moraes TF. A secreted bacterial protein protects bacteria from cationic antimicrobial peptides by entrapment in phase-separated droplets. PNAS NEXUS 2024; 3:pgae139. [PMID: 38633880 PMCID: PMC11022072 DOI: 10.1093/pnasnexus/pgae139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
Mammalian hosts combat bacterial infections through the production of defensive cationic antimicrobial peptides (CAPs). These immune factors are capable of directly killing bacterial invaders; however, many pathogens have evolved resistance evasion mechanisms such as cell surface modification, CAP sequestration, degradation, or efflux. We have discovered that several pathogenic and commensal proteobacteria, including the urgent human threat Neisseria gonorrhoeae, secrete a protein (lactoferrin-binding protein B, LbpB) that contains a low-complexity anionic domain capable of inhibiting the antimicrobial activity of host CAPs. This study focuses on a cattle pathogen, Moraxella bovis, that expresses the largest anionic domain of the LbpB homologs. We used an exhaustive biophysical approach employing circular dichroism, biolayer interferometry, cross-linking mass spectrometry, microscopy, size-exclusion chromatography with multi-angle light scattering coupled to small-angle X-ray scattering (SEC-MALS-SAXS), and NMR to understand the mechanisms of LbpB-mediated protection against CAPs. We found that the anionic domain of this LbpB displays an α-helical secondary structure but lacks a rigid tertiary fold. The addition of antimicrobial peptides derived from lactoferrin (i.e. lactoferricin) to the anionic domain of LbpB or full-length LbpB results in the formation of phase-separated droplets of LbpB together with the antimicrobial peptides. The droplets displayed a low rate of diffusion, suggesting that CAPs become trapped inside and are no longer able to kill bacteria. Our data suggest that pathogens, like M. bovis, leverage anionic intrinsically disordered domains for the broad recognition and neutralization of antimicrobials via the formation of biomolecular condensates.
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Affiliation(s)
- Nicholas K H Ostan
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Gregory B Cole
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Flora Zhiqi Wang
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Sean E Reichheld
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Gaelen Moore
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Chuxi Pan
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ronghua Yu
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB T2N 4N1, Canada
| | | | - Simon Sharpe
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Hyun O Lee
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Anthony B Schryvers
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Trevor F Moraes
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
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5
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Belagal P. Current alternative therapies for treating drug-resistant Neisseria gonorrhoeae causing ophthalmia neonatorum. Future Microbiol 2024. [PMID: 38512111 DOI: 10.2217/fmb-2023-0251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024] Open
Abstract
Ophthalmia neonatorum is a microbial contraction, damaging eyesight, occurring largely among neonates. Infants are particularly vulnerable to bacterial infections acquired during birth from infected mothers, especially from Neisseria gonorrhoeae and Chlamydia trachomatis. Over the decades, N. gonorrhoeae is alarmingly developing a resistance to most antibiotics currently prescribed. To counter this challenge, it is imperative to find potent and cost-effective therapeutic agents for prophylaxis and treatment, to which the N. gonorrhoeae cannot easily develop resistance. This review showcases alternate therapies such as antimicrobial-fatty acids, -peptides, -nano-formulations etc., currently evident against N. gonorrhoeae-mediated ophthalmia neonatorum, which remains a major cause of ocular morbidity, blindness and even death among neonates in developing countries.
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Huang PW, Liou CY, Lee YC, Wei TY, Ho HC, Yang TY, Wang LC. The Evaluation of Teleost-Derived Antimicrobial Peptides Against Neisseria gonorrhoeae. Cureus 2024; 16:e57168. [PMID: 38681331 PMCID: PMC11056026 DOI: 10.7759/cureus.57168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2024] [Indexed: 05/01/2024] Open
Abstract
Introduction Gonorrhea has become an emerging sexually transmitted infection worldwide. The multi-antibiotic resistance facilitates the transmission; thus, new antibiotics or alternatives are needed. Antimicrobial peptides (AMP) are antimicrobials naturally secreted by the host as a defense material. Teleost-derived AMP have gained attention over the past two decades due to their potent efficacy toward microorganisms. This study examines teleost-derived AMP against Neisseria gonorrhoeae (GC), the responsible bacteria for gonorrhea, to evaluate the antibiotic potential as a future alternative for preventing gonorrhea. Methods Minimal inhibitory concentration (MIC) and time-killed assay were conducted to evaluate the inhibition concentration of each AMP. Transmission electron microscopy was used to confirm the potential mode of action. The inhibition of microcolony formation and adherence to epithelial cells were examined to assess the infection inhibition. Results Pardaxin-based (flatfish pardaxin {PB2}) and piscidin-based (striped bass piscidin 1 {PIS} and tilapia piscidin {TP} 4) AMP were effective toward GC under or equal to 7.5 μg/mL as of minimal inhibitory concentration. Transmission electron microscopy images revealed that these AMP attack bacterial membranes as membrane blebbing and breakage were observed. These AMP also effectively reduced the GC biofilm formation, as well as their adherence to human endocervical epithelial cells. Conclusion Pardaxin-based (PB2) and piscidin-based (PIS and TP4) teleost-derived AMP can inhibit GC and potentially serve as the new antibiotic alternative for preventing GC colonization and infection. This study will shed some light on the future development of teleost-derived AMP in treating gonorrhea and maintaining reproductive health.
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Affiliation(s)
- Po-Wei Huang
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, TWN
- Division of Urology, Department of Surgery, Zuoying Armed Forces General Hospital, Kaohsiung, TWN
- Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Kaohsiung, TWN
- Center of General Education, Shu-Zen Junior College of Medicine and Management, Kaohsiung, TWN
| | - Chung-Yi Liou
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, TWN
| | - Ying-Chen Lee
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, TWN
| | - Tzu-Yu Wei
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, TWN
| | - Han-Chen Ho
- Department of Anatomy, Tzu Chi University, Hualien, TWN
| | - Tsung-Ying Yang
- Department of Medical Laboratory Science, I-Shou University, Kaohsiung, TWN
| | - Liang-Chun Wang
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, TWN
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Hooks GM, Ayala JC, Holley CL, Dhulipala V, Beggs GA, Perfect JR, Schumacher MA, Shafer WM, Brennan RG. Hormonal steroids induce multidrug resistance and stress response genes in Neisseria gonorrhoeae by binding to MtrR. Nat Commun 2024; 15:1153. [PMID: 38326294 PMCID: PMC10850145 DOI: 10.1038/s41467-024-45195-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/16/2024] [Indexed: 02/09/2024] Open
Abstract
Transcriptional regulator MtrR inhibits the expression of the multidrug efflux pump operon mtrCDE in the pathogenic bacterium Neisseria gonorrhoeae. Here, we show that MtrR binds the hormonal steroids progesterone, β-estradiol, and testosterone, which are present at urogenital infection sites, as well as ethinyl estrogen, a component of some hormonal contraceptives. Steroid binding leads to the decreased affinity of MtrR for cognate DNA, increased mtrCDE expression, and enhanced antimicrobial resistance. Furthermore, we solve crystal structures of MtrR bound to each steroid, thus revealing their binding mechanisms and the conformational changes that induce MtrR.
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Affiliation(s)
- Grace M Hooks
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Julio C Ayala
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
- STD Laboratory Reference and Research Branch, Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Concerta L Holley
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
| | - Vijaya Dhulipala
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
| | - Grace A Beggs
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - John R Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Maria A Schumacher
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - William M Shafer
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
- Laboratories of Microbial Pathogenesis, VA Medical Research Service, Veterans Affairs Medical Center, Decatur, GA, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Richard G Brennan
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.
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Savitskaya A, Masso-Silva J, Haddaoui I, Enany S. Exploring the arsenal of antimicrobial peptides: Mechanisms, diversity, and applications. Biochimie 2023; 214:216-227. [PMID: 37499896 DOI: 10.1016/j.biochi.2023.07.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/09/2023] [Accepted: 07/24/2023] [Indexed: 07/29/2023]
Abstract
Antimicrobial peptides (AMPs) are essential for defence against pathogens in all living organisms and possessed activities against bacteria, fungi, viruses, parasites and even cancer cells. AMPs are short peptides containing 12-100 amino acids conferring a net positive charge and an amphiphilic property in most cases. Although, anionic AMPs also exist. AMPs can be classified based on the types of secondary structures, charge, hydrophobicity, amino acid composition, length, etc. Their mechanism of action usually includes a membrane disruption process through pore formation (three different models have been described, barrel-stave, toroidal or carpet model) but AMPs can also penetrate and impair intracellular functions. Besides their activity against pathogens, they have also shown immunomodulatory properties in complex scenarios through many different interactions. The aim of this review to summarize knowledge about AMP's and discuss the potential application of AMPs as therapeutics, the challenges due to their limitations, including their susceptibility to degradation, the potential generation of AMP resistance, cost, etc. We also discuss the current FDA-approved drugs based on AMPs and strategies to circumvent natural AMPs' limitations.
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Affiliation(s)
- Anna Savitskaya
- Institute of Bioorganic Chemistry of Russian Academy of Science, Moscow, Russian Federation
| | - Jorge Masso-Silva
- Division of Pulmonary, Critical Care, Sleep Medicine and Physiology, University of California San Diego, La Jolla, CA, USA
| | - Imen Haddaoui
- National Research Institute of Rural Engineering, Water and Forestry, University of Carthage, LR Valorization of Unconventional Waters, Ariana, Tunisia
| | - Shymaa Enany
- Microbiology and Immunology Department, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt; Biomedical Research Department, Armed Force College of Medicine, Cairo, Egypt.
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Neidig A, Strempel N, Waeber NB, Nizer WSDC, Overhage J. Knock-out of multidrug efflux pump MexXY-OprM results in increased susceptibility to antimicrobial peptides in Pseudomonas aeruginosa. Microbiol Immunol 2023; 67:422-427. [PMID: 37424105 DOI: 10.1111/1348-0421.13089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/12/2023] [Accepted: 06/22/2023] [Indexed: 07/11/2023]
Abstract
Multidrug efflux systems of the resistance-nodulation-cell division family play a crucial role in resistance of Pseudomonas aeruginosa to a large variety of antibiotics. Here, we investigated the role of clinically relevant efflux pumps MexAB- OprM, MexCD- OprJ, and MexXY- OprM in resistance against different cationic antimicrobial peptides (AMPs). Our results indicate that a knock-out in efflux pump MexXY-OprM increased susceptibility to some AMPs by two- to eightfold. Our data suggest a contribution of MexXY-OprM in resistance to certain AMPs in P. aeruginosa, which should be considered in the future development of new and highly active antimicrobial peptides to fight multidrug resistant infections.
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Affiliation(s)
- Anke Neidig
- Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Nikola Strempel
- Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Nadine Bianca Waeber
- Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute of Biochemistry, Justus-Liebig-University of Giessen, Giessen, Germany
| | | | - Joerg Overhage
- Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Department of Health Sciences, Carleton University, Ottawa, Ontario, Canada
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10
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Belcher T, Rollier CS, Dold C, Ross JDC, MacLennan CA. Immune responses to Neisseria gonorrhoeae and implications for vaccine development. Front Immunol 2023; 14:1248613. [PMID: 37662926 PMCID: PMC10470030 DOI: 10.3389/fimmu.2023.1248613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 07/26/2023] [Indexed: 09/05/2023] Open
Abstract
Neisseria gonorrheoae is the causative agent of gonorrhea, a sexually transmitted infection responsible for a major burden of disease with a high global prevalence. Protective immunity to infection is often not observed in humans, possible due to high variability of key antigens, induction of blocking antibodies, or a large number of infections being relatively superficial and not inducing a strong immune response. N. gonorrhoeae is a strictly human pathogen, however, studies using mouse models provide useful insights into the immune response to gonorrhea. In mice, N. gonorrhoea appears to avoid a protective Th1 response by inducing a less protective Th17 response. In mouse models, candidate vaccines which provoke a Th1 response can accelerate the clearance of gonococcus from the mouse female genital tract. Human studies indicate that natural infection often induces a limited immune response, with modest antibody responses, which may correlate with the clinical severity of gonococcal disease. Studies of cytokine responses to gonococcal infection in humans provide conflicting evidence as to whether infection induces an IL-17 response. However, there is evidence for limited induction of protective immunity from a study of female sex workers in Kenya. A controlled human infection model (CHIM) has been used to examine the immune response to gonococcal infection in male volunteers, but has not to date demonstrated protection against re-infection. Correlates of protection for gonorrhea are lacking, which has hampered the progress towards developing a successful vaccine. However, the finding that the Neisseria meningitidis serogroup B vaccines, elicit cross-protection against gonorrhea has invigorated the gonococcal vaccine field. More studies of infection in humans, either natural infection or CHIM studies, are needed to understand better gonococcal protective immunity.
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Affiliation(s)
- Thomas Belcher
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Christina Dold
- The Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
| | - Jonathan D. C. Ross
- Sexual Health and HIV, University Hospitals Birmingham NHS Trust, Birmingham, United Kingdom
| | - Calman A. MacLennan
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Waltmann A, Balthazar JT, Begum AA, Hua N, Jerse AE, Shafer WM, Hobbs MM, Duncan JA. Neisseria gonorrhoeae MtrCDE Efflux Pump During In Vivo Experimental Genital Tract Infection in Men and Mice Reveals the Presence of Within-Host Colonization Bottleneck. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.06.23.23291824. [PMID: 37425726 PMCID: PMC10327229 DOI: 10.1101/2023.06.23.23291824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The MtrCDE efflux pump of Neisseria gonorrhoeae exports a wide range of antimicrobial compounds that the gonococcus encounters at mucosal surfaces during colonization and infection. Here, we evaluate the role of this efflux pump system in strain FA1090 in human male urethral infection with a Controlled Human Infection Model. Using the strategy of competitive multi-strain infection with wild-type FA1090 and an isogenic mutant strain that does not contain a functional MtrCDE pump, we found that the presence of the efflux pump during human experimental infection did not confer a competitive advantage. This finding is in contrast to previous findings in female mice, which demonstrated that gonococci of strain FA19 lacking a functional MtrCDE pump had a significantly reduced fitness compared to the wild type strain in the lower genital tract of female mice. We conducted competitive infections in female mice with FA19 and FA1090 strains, including mutants that do not assemble a functional Mtr efflux pump, demonstrating the fitness advantage provided byt the MtrCDE efflux pump during infection of mice is strain dependent. Our data indicate that new gonorrhea treatment strategies targeting the MtrCDE efflux pump functions may not be universally efficacious in naturally occurring infections. Owing to the equal fitness of FA1090 strains in men, our experiments unexpectedly demonstrated the likely presence of an early colonization bottleneck of N. gonorrhoeae in the human male urethra. TRIAL REGISTRATION Clinicaltrials.gov NCT03840811 .
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12
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Hooks GM, Ayala JC, Beggs GA, Perfect JR, Schumacher MA, Shafer WM, Brennan RG. Hormonal steroids bind the Neisseria gonorrhoeae multidrug resistance regulator, MtrR, to induce a multidrug binding efflux pump and stress-response sigma factor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.13.544409. [PMID: 37398116 PMCID: PMC10312642 DOI: 10.1101/2023.06.13.544409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Overexpression of the multidrug efflux pump MtrCDE, a critical factor of multidrug-resistance in Neisseria gonorrhoeae , the causative agent of gonorrheae, is repressed by the transcriptional regulator, MtrR (multiple transferable resistance repressor). Here, we report the results from a series of in vitro experiments to identify innate, human inducers of MtrR and to understand the biochemical and structural mechanisms of the gene regulatory function of MtrR. Isothermal titration calorimetry experiments reveal that MtrR binds the hormonal steroids progesterone, β-estradiol, and testosterone, all of which are present at significant concentrations at urogenital infection sites as well as ethinyl estrogen, a component of some birth control pills. Binding of these steroids results in decreased affinity of MtrR for cognate DNA, as demonstrated by fluorescence polarization-based assays. The crystal structures of MtrR bound to each steroid provided insight into the flexibility of the binding pocket, elucidated specific residue-ligand interactions, and revealed the conformational consequences of the induction mechanism of MtrR. Three residues, D171, W136 and R176 are key to the specific binding of these gonadal steroids. These studies provide a molecular understanding of the transcriptional regulation by MtrR that promotes N. gonorrhoeae survival in its human host.
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13
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Li T, Wang Z, Guo J, de la Fuente-Nunez C, Wang J, Han B, Tao H, Liu J, Wang X. Bacterial resistance to antibacterial agents: Mechanisms, control strategies, and implications for global health. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 860:160461. [PMID: 36435256 DOI: 10.1016/j.scitotenv.2022.160461] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 11/19/2022] [Accepted: 11/20/2022] [Indexed: 06/16/2023]
Abstract
The spread of bacterial drug resistance has posed a severe threat to public health globally. Here, we cover bacterial resistance to current antibacterial drugs, including traditional herbal medicines, conventional antibiotics, and antimicrobial peptides. We summarize the influence of bacterial drug resistance on global health and its economic burden while highlighting the resistance mechanisms developed by bacteria. Based on the One Health concept, we propose 4A strategies to combat bacterial resistance, including prudent Application of antibacterial agents, Administration, Assays, and Alternatives to antibiotics. Finally, we identify several opportunities and unsolved questions warranting future exploration for combating bacterial resistance, such as predicting genetic bacterial resistance through the use of more effective techniques, surveying both genetic determinants of bacterial resistance and the transmission dynamics of antibiotic resistance genes (ARGs).
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Affiliation(s)
- Ting Li
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China; State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20, Dongda Street, Fengtai District, Beijing 100071, PR China
| | - Zhenlong Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Jianhua Guo
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St Lucia, Queensland 4072, Australia.
| | - Cesar de la Fuente-Nunez
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America; Departments of Bioengineering and Chemical and Biomolecular Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States of America; Penn Institute for Computational Science, University of Pennsylvania, Philadelphia, PA, United States of America.
| | - Jinquan Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Bing Han
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Hui Tao
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Jie Liu
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Xiumin Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China.
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14
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Hampton MB, Dickerhof N. Inside the phagosome: A bacterial perspective. Immunol Rev 2023; 314:197-209. [PMID: 36625601 DOI: 10.1111/imr.13182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The neutrophil phagosome is one of the most hostile environments that bacteria must face and overcome if they are to succeed as pathogens. Targeting bacterial defense mechanisms should lead to new therapies that assist neutrophils to kill pathogens, but this has not yet come to fruition. One of the limiting factors in this effort has been our incomplete knowledge of the complex biochemistry that occurs within the rapidly changing environment of the phagosome. The same compartmentalization that protects host tissue also limits our ability to measure events within the phagosome. In this review, we highlight the limitations in our knowledge, and how the contribution of bacteria to the phagosomal environment is often ignored. There appears to be significant heterogeneity among phagosomes, and it is important to determine whether survivors have more efficient defenses or whether they are ingested into less threatening environments than other bacteria. As part of these efforts, we discuss how monitoring or recovering bacteria from phagosomes can provide insight into the conditions they have faced. We also encourage the use of unbiased screening approaches to identify bacterial genes that are essential for survival inside neutrophil phagosomes.
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Affiliation(s)
- Mark B Hampton
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | - Nina Dickerhof
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
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15
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Structural Basis of Peptide-Based Antimicrobial Inhibition of a Resistance-Nodulation-Cell Division Multidrug Efflux Pump. Microbiol Spectr 2022; 10:e0299022. [PMID: 36121287 PMCID: PMC9603588 DOI: 10.1128/spectrum.02990-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Bacterial efflux pumps in the resistance-nodulation-cell division (RND) family of Gram-negative bacteria contribute significantly to the development of antimicrobial resistance by many pathogens. In this study, we selected the MtrD transporter protein of Neisseria gonorrhoeae as it is the sole RND pump possessed by this strictly human pathogen and can export multiple antimicrobials, including antibiotics, bile salts, detergents, dyes, and antimicrobial peptides. Using knowledge from our previously published structures of MtrD in the presence or absence of bound antibiotics as a model and the known ability of MtrCDE to export cationic antimicrobial peptides, we hypothesized that cationic peptides could be accommodated within MtrD binding sites. Furthermore, we thought that MtrD-bound peptides lacking antibacterial action could sensitize bacteria to an antibiotic normally exported by the MtrCDE efflux pump or other similar RND-type pumps possessed by different Gram-negative bacteria. We now report the identification of a novel nonantimicrobial cyclic cationic antimicrobial peptide, which we termed CASP (cationic antibiotic-sensitizing peptide). By single-particle cryo-electron microscopy, we found that CASP binds within the periplasmic cleft region of MtrD using overlapping and distinct amino acid contact sites that interact with another cyclic peptide (colistin) or a linear human cationic antimicrobial peptide derived from human LL-37. While CASP could not sensitize Neisseria gonorrhoeae to an antibiotic (novobiocin) that is a substrate for RND pumps, it could do so against multiple Gram-negative, rod-shaped bacteria. We propose that CASP (or future derivatives) could serve as an adjuvant for the antibiotic treatment of certain Gram-negative infections previously thwarted by RND transporters. IMPORTANCE RND efflux pumps can export numerous antimicrobials that enter Gram-negative bacteria, and their action can reduce the efficacy of antibiotics and provide decreased susceptibility to various host antimicrobials. Here, we identified a cationic antibiotic-sensitizing peptide (CASP) that binds within the periplasmic cleft of an RND transporter protein (MtrD) produced by Neisseria gonorrhoeae. Surprisingly, CASP was able to render rod-shaped Gram-negative bacteria, but not gonococci, susceptible to an antibiotic that is a substrate for the gonococcal MtrCDE efflux pump. CASP (or its future derivatives) could be used as an adjuvant to treat infections for which RND efflux contributes to multidrug resistance.
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16
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Ayala JC, Balthazar JT, Shafer WM. Transcriptional regulation of the mtrCDE efflux pump operon: importance for Neisseria gonorrhoeae antimicrobial resistance. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35916832 DOI: 10.1099/mic.0.001231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This review focuses on the mechanisms of transcriptional control of an important multidrug efflux pump system (MtrCDE) possessed by Neisseria gonorrhoeae, the aetiological agent of the sexually transmitted infection termed gonorrhoea. The mtrCDE operon that encodes this tripartite protein efflux pump is subject to both cis- and trans-acting transcriptional factors that negatively or positively influence expression. Critically, levels of MtrCDE can influence levels of gonococcal susceptibility to classical antibiotics, host-derived antimicrobials and various biocides. The regulatory systems that control mtrCDE can have profound influences on the capacity of gonococci to resist current and past antibiotic therapy regimens as well as virulence. The emergence, mechanisms of action and clinical significance of the transcriptional regulatory systems that impact mtrCDE expression in gonococci are reviewed here with the aim of linking bacterial antimicrobial resistance with multidrug efflux capability.
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Affiliation(s)
- Julio C Ayala
- Department of Microbiology and Immunology Emory University School of Medicine, Atlanta, Georgia, 30322, USA
| | - Jacqueline T Balthazar
- Department of Microbiology and Immunology Emory University School of Medicine, Atlanta, Georgia, 30322, USA
| | - William M Shafer
- Department of Microbiology and Immunology Emory University School of Medicine, Atlanta, Georgia, 30322, USA.,Laboratories of Bacterial Pathogenesis, VA Medical Center (Atlanta), Decatur, Georgia, 30033, USA.,The Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
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17
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Blair JMA, Zeth K, Bavro VN, Sancho-Vaello E. The role of bacterial transport systems in the removal of host antimicrobial peptides in Gram-negative bacteria. FEMS Microbiol Rev 2022; 46:6617596. [PMID: 35749576 PMCID: PMC9629497 DOI: 10.1093/femsre/fuac032] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 05/23/2022] [Accepted: 06/22/2022] [Indexed: 01/09/2023] Open
Abstract
Antibiotic resistance is a global issue that threatens our progress in healthcare and life expectancy. In recent years, antimicrobial peptides (AMPs) have been considered as promising alternatives to the classic antibiotics. AMPs are potentially superior due to their lower rate of resistance development, since they primarily target the bacterial membrane ('Achilles' heel' of the bacteria). However, bacteria have developed mechanisms of AMP resistance, including the removal of AMPs to the extracellular space by efflux pumps such as the MtrCDE or AcrAB-TolC systems, and the internalization of AMPs to the cytoplasm by the Sap transporter, followed by proteolytic digestion. In this review, we focus on AMP transport as a resistance mechanism compiling all the experimental evidence for the involvement of efflux in AMP resistance in Gram-negative bacteria and combine this information with the analysis of the structures of the efflux systems involved. Finally, we expose some open questions with the aim of arousing the interest of the scientific community towards the AMPs-efflux pumps interactions. All the collected information broadens our understanding of AMP removal by efflux pumps and gives some clues to assist the rational design of AMP-derivatives as inhibitors of the efflux pumps.
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Affiliation(s)
- Jessica M A Blair
- College of Medical and Dental Sciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Kornelius Zeth
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark
| | - Vassiliy N Bavro
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, United Kingdom
| | - Enea Sancho-Vaello
- Corresponding author. College of Medical and Dental Sciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom. E-mail:
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18
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Hu LI, Stohl EA, Seifert HS. The Neisseria gonorrhoeae type IV pilus promotes resistance to hydrogen peroxide- and LL-37-mediated killing by modulating the availability of intracellular, labile iron. PLoS Pathog 2022; 18:e1010561. [PMID: 35714158 PMCID: PMC9246397 DOI: 10.1371/journal.ppat.1010561] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 06/30/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022] Open
Abstract
The Neisseria gonorrhoeae Type IV pilus is a multifunctional, dynamic fiber involved in host cell attachment, DNA transformation, and twitching motility. We previously reported that the N. gonorrhoeae pilus is also required for resistance against hydrogen peroxide-, antimicrobial peptide LL-37-, and non-oxidative, neutrophil-mediated killing. We tested whether the hydrogen peroxide, LL-37, and neutrophil hypersensitivity phenotypes in non-piliated N. gonorrhoeae could be due to elevated iron levels. Iron chelation in the growth medium rescued a nonpiliated pilE mutant from both hydrogen peroxide- and antimicrobial peptide LL-37-mediated killing, suggesting these phenotypes are related to iron availability. We used the antibiotic streptonigrin, which depends on free cytoplasmic iron and oxidation to kill bacteria, to determine whether piliation affected intracellular iron levels. Several non-piliated, loss-of-function mutants were more sensitive to streptonigrin killing than the piliated parental strain. Consistent with the idea that higher available iron levels in the under- and non-piliated strains were responsible for the higher streptonigrin sensitivity, iron limitation by desferal chelation restored resistance to streptonigrin in these strains and the addition of iron restored the sensitivity to streptonigrin killing. The antioxidants tiron and dimethylthiourea rescued the pilE mutant from streptonigrin-mediated killing, suggesting that the elevated labile iron pool in non-piliated bacteria leads to streptonigrin-dependent reactive oxygen species production. These antioxidants did not affect LL-37-mediated killing. We confirmed that the pilE mutant is not more sensitive to other antibiotics showing that the streptonigrin phenotypes are not due to general bacterial envelope disruption. The total iron content of the cell was unaltered by piliation when measured using ICP-MS suggesting that only the labile iron pool is affected by piliation. These results support the hypothesis that piliation state affects N. gonorrhoeae iron homeostasis and influences sensitivity to various host-derived antimicrobial agents. Neisseria gonorrhoeae is a bacterium that causes the sexually transmitted infection, gonorrhea. The bacteria express a fiber on their surface called a pilus that mediates many interactions of the bacterial cell with host cells and tissues. The ability to resist killing by white cells is one important ability that N. gonorrhoeae uses to allow infection of otherwise healthy people. We show here that the pilus help resist white cell killing by modulating the levels of iron within the bacterial cell.
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Affiliation(s)
- Linda I. Hu
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Elizabeth A. Stohl
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - H Steven Seifert
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- * E-mail:
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19
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MacDermott-Opeskin HI, Gupta V, O’Mara ML. Lipid-mediated antimicrobial resistance: a phantom menace or a new hope? Biophys Rev 2022; 14:145-162. [PMID: 35251360 PMCID: PMC8880301 DOI: 10.1007/s12551-021-00912-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/14/2021] [Indexed: 02/06/2023] Open
Abstract
Abstract The proposition of a post-antimicrobial era is all the more realistic with the continued rise of antimicrobial resistance. The development of new antimicrobials is failing to counter the ever-increasing rates of bacterial antimicrobial resistance. This necessitates novel antimicrobials and drug targets. The bacterial cell membrane is an essential and highly conserved cellular component in bacteria and acts as the primary barrier for entry of antimicrobials into the cell. Although previously under-exploited as an antimicrobial target, the bacterial cell membrane is attractive for the development of novel antimicrobials due to its importance in pathogen viability. Bacterial cell membranes are diverse assemblies of macromolecules built around a central lipid bilayer core. This lipid bilayer governs the overall membrane biophysical properties and function of its membrane-embedded proteins. This mini-review will outline the mechanisms by which the bacterial membrane causes and controls resistance, with a focus on alterations in the membrane lipid composition, chemical modification of constituent lipids, and the efflux of antimicrobials by membrane-embedded efflux systems. Thorough insight into the interplay between membrane-active antimicrobials and lipid-mediated resistance is needed to enable the rational development of new antimicrobials. In particular, the union of computational approaches and experimental techniques for the development of innovative and efficacious membrane-active antimicrobials is explored.
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Affiliation(s)
- Hugo I. MacDermott-Opeskin
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Vrinda Gupta
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Megan L. O’Mara
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
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20
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Antimicrobial Peptides as a Promising Therapeutic Strategy for Neisseria Infections. Curr Microbiol 2022; 79:102. [DOI: 10.1007/s00284-022-02767-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 01/13/2022] [Indexed: 11/03/2022]
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21
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Zaknoon F, Meir O, Mor A. Mechanistic Studies of Antibiotic Adjuvants Reducing Kidney's Bacterial Loads upon Systemic Monotherapy. Pharmaceutics 2021; 13:pharmaceutics13111947. [PMID: 34834362 PMCID: PMC8621570 DOI: 10.3390/pharmaceutics13111947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 11/11/2021] [Accepted: 11/14/2021] [Indexed: 12/01/2022] Open
Abstract
We describe the design and attributes of a linear pentapeptide-like derivative (C14(ω5)OOc10O) screened for its ability to elicit bactericidal competences of plasma constituents against Gram-negative bacteria (GNB). In simpler culture media, the lipopeptide revealed high aptitudes to sensitize resilient GNB to hydrophobic and/or efflux-substrate antibiotics, whereas in their absence, C14(ω5)OOc10O only briefly delayed bacterial proliferation. Instead, at low micromolar concentrations, the lipopeptide has rapidly lowered bacterial proton and ATP levels, although significantly less than upon treatment with its bactericidal analog. Mechanistic studies support a two-step scenario providing a plausible explanation for the lipopeptide’s biological outcomes against GNB: initially, C14(ω5)OOc10O permeabilizes the outer membrane similarly to polymyxin B, albeit in a manner not necessitating as much LPS-binding affinity. Subsequently, C14(ω5)OOc10O would interact with the inner membrane gently yet intensively enough to restrain membrane-protein functions such as drug efflux and/or ATP generation, while averting the harsher inner membrane perturbations that mediate the fatal outcome associated with bactericidal peers. Preliminary in vivo studies where skin wound infections were introduced in mice, revealed a significant efficacy in affecting bacterial viability upon topical treatment with creams containing C14(ω5)OOc10O, whereas synergistic combination therapies were able to secure the pathogen’s eradication. Further, capitalizing on the finding that C14(ω5)OOc10O plasma-potentiating concentrations were attainable in mice blood at sub-maximal tolerated doses, we used a urinary tract infection model to acquire evidence for the lipopeptide’s systemic capacity to reduce the kidney’s bacterial loads. Collectively, the data establish the role of C14(ω5)OOc10O as a compelling antibacterial potentiator and suggest its drug-like potential.
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22
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Self-inhibitory peptides targeting the Neisseria gonorrhoeae MtrCDE efflux pump increase antibiotic susceptibility. Antimicrob Agents Chemother 2021; 66:e0154221. [PMID: 34633841 PMCID: PMC8765275 DOI: 10.1128/aac.01542-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neisseria gonorrhoeae is an increasing public health threat due to rapidly rising incidence and antibiotic resistance. There are an estimated 106 million cases per year worldwide, there is no vaccine available to prevent infection, and N. gonorrhoeae strains have emerged that are resistant to all antibiotics routinely used to treat the infection. In many strains, antibiotic resistance is mediated by overexpression of the MtrCDE efflux pump, which enables the bacteria to transport toxic antibiotics out of the cell. Genetic mutations that inactivate MtrCDE have previously been shown to render resistant strains susceptible to certain antibiotics. Here we have shown that peptides rationally-designed to target and disrupt the activity of each of the three protein components of MtrCDE were able to increase the susceptibility of N. gonorrhoeae strains to antibiotics, in a dose-dependent manner and with no toxicity to human cells. Co-treatment of bacteria with subinhibitory concentrations of peptide led to 2-64 fold increases in the susceptibility to erythromycin, azithromycin, ciprofloxacin and/or ceftriaxone in N. gonorrhoeae strains FA1090, WHO K, WHO P and WHO X. The co-treatment experiments with peptides P-MtrC1 and P-MtrE1 resulted in increased susceptibility to azithromycin, ciprofloxacin and ceftriaxone in WHO P and WHO X that was of the same magnitude seen in MtrCDE mutants. P-MtrE1 was able to change the azithromycin resistance profile of WHO P from resistant to susceptible. Data presented here demonstrate that these peptides could be developed for use as a dual treatment with existing antibiotics to treat multidrug-resistant gonococcal infections.
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23
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A Unique Sequence Is Essential for Efficient Multidrug Efflux Function of the MtrD Protein of Neisseria gonorrhoeae. mBio 2021; 12:e0167521. [PMID: 34465021 PMCID: PMC8406276 DOI: 10.1128/mbio.01675-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial resistance in Neisseria gonorrhoeae has reached an alarming level, severely impacting the effective treatment of gonorrhea. Belonging to the resistance-nodulation-cell division (RND) superfamily of efflux transporters, the MtrD membrane protein of N. gonorrhoeae provides resistance to a broad range of antimicrobial compounds. A unique feature of MtrD is an 11-residue sequence (from N917 to P927 [N917-P927]) that connects transmembrane helices (TMS) 9 and 10; this sequence is not present in homologous RND proteins. This study explores the structural and functional roles of the N917-P927 region by means of mutant analysis and molecular dynamics simulations. We show that N917-P927 plays a key role in modulating substrate access to the binding cleft and influences the overall orientation of the protein within the inner membrane necessary for optimal functioning. Removal of N917-P927 significantly reduced MtrD-mediated resistance to a range of antimicrobials and mutations of three single amino acids impacted MtrD-mediated multidrug resistance. Furthermore, molecular dynamics simulations showed deletion of N917-P927 in MtrD may dysregulate access of the substrate to the binding cleft and closure of the substrate-binding pocket during the transport cycle. These findings indicate that N917-P927 is a key region for interacting with the inner membrane, conceivably influencing substrate capture from the membrane-periplasm interface and thus is essential for full multidrug resistance capacity of MtrD. IMPORTANCE The historical sexually transmitted infection gonorrhea continues to be a major public health concern with an estimated global annual incidence of 86.9 million cases. N. gonorrhoeae has been identified by the World Health Organization as one of the 12 antimicrobial-resistant bacterial species that poses the greatest risk to human health. As the major efflux pump in gonococci, the MtrD transporter contributes to the cell envelope barrier in this organism and pumps antimicrobials from the periplasm and inner membrane, resulting in resistance. This study demonstrates that a unique region of the MtrD protein that connects TMS 9 and TMS 10 forms a structure that may interact with the inner membrane positioning TMS 9 and stabilizing the protein facilitating substrate capture from the inner membrane-periplasm interface. Analysis of mutants of this region identified that it was essential for MtrD-mediated multidrug resistance. Characterization of the structure and function of this unique local region of MtrD has implications for drug efflux mechanisms used by related proteins and is important knowledge for development of antibiotics that bypass efflux.
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24
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Fairweather SJ, Gupta V, Chitsaz M, Booth L, Brown MH, O’Mara ML. Coordination of Substrate Binding and Protonation in the N. gonorrhoeae MtrD Efflux Pump Controls the Functionally Rotating Transport Mechanism. ACS Infect Dis 2021; 7:1833-1847. [PMID: 33980014 DOI: 10.1021/acsinfecdis.1c00149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multidrug resistance is a serious problem that threatens the effective treatment of the widespread sexually transmitted disease gonorrhea, caused by the Gram-negative bacterium Neisseria gonorrhoeae. The drug efflux pump primarily implicated in N. gonorrhoeae antimicrobial resistance is the inner membrane transporter MtrD, which forms part of the tripartite multiple transferable resistance (Mtr) CDE efflux system. A structure of MtrD was first solved in 2014 as a symmetrical homotrimer, and then, recently, as an asymmetrical homotrimer. Through a series of molecular dynamics simulations and mutagenesis experiments, we identify the combination of substrate binding and protonation states of the proton relay network that drives the transition from the symmetric to the asymmetric conformation of MtrD. We characterize the allosteric coupling between the functionally important local regions that control conformational changes between the access, binding, and extrusion states and allow for transition to the asymmetric MtrD conformation. We also highlight a significant rotation of the transmembrane helices caused by protonation of the proton relay network, which widens the intermonomeric gap that is a hallmark of the rotational transporter mechanism. This is the first analysis and description of the transport mechanism for the N. gonorrhoeae MtrD transporter and provides evidence that antimicrobial efflux in MtrD follows the functionally rotating transport mechanism seen in protein homologues from the same transport protein superfamily.
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Affiliation(s)
- Stephen J. Fairweather
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Vrinda Gupta
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
| | - Mohsen Chitsaz
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Lauren Booth
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
| | - Melissa H. Brown
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Megan L. O’Mara
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
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25
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Abstract
When attempting to propagate infections, bacterial pathogens encounter phagocytes that encase them in vacuoles called phagosomes. Within phagosomes, bacteria are bombarded with a plethora of stresses that often lead to their demise. However, pathogens have evolved numerous strategies to counter those host defenses and facilitate survival. Given the importance of phagosome-bacteria interactions to infection outcomes, they represent a collection of targets that are of interest for next-generation antibacterials. To facilitate such therapies, different approaches can be employed to increase understanding of phagosome-bacteria interactions, and these can be classified broadly as top down (starting from intact systems and breaking down the importance of different parts) or bottom up (developing a knowledge base on simplified systems and progressively increasing complexity). Here we review knowledge of phagosomal compositions and bacterial survival tactics useful for bottom-up approaches, which are particularly relevant for the application of reaction engineering to quantify and predict the time evolution of biochemical species in these death-dealing vacuoles. Further, we highlight how understanding in this area can be built up through the combination of immunology, microbiology, and engineering.
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Affiliation(s)
- Darshan M Sivaloganathan
- Program in Quantitative and Computational Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Mark P Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA;
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26
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Henderson PJF, Maher C, Elbourne LDH, Eijkelkamp BA, Paulsen IT, Hassan KA. Physiological Functions of Bacterial "Multidrug" Efflux Pumps. Chem Rev 2021; 121:5417-5478. [PMID: 33761243 DOI: 10.1021/acs.chemrev.0c01226] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial multidrug efflux pumps have come to prominence in human and veterinary pathogenesis because they help bacteria protect themselves against the antimicrobials used to overcome their infections. However, it is increasingly realized that many, probably most, such pumps have physiological roles that are distinct from protection of bacteria against antimicrobials administered by humans. Here we undertake a broad survey of the proteins involved, allied to detailed examples of their evolution, energetics, structures, chemical recognition, and molecular mechanisms, together with the experimental strategies that enable rapid and economical progress in understanding their true physiological roles. Once these roles are established, the knowledge can be harnessed to design more effective drugs, improve existing microbial production of drugs for clinical practice and of feedstocks for commercial exploitation, and even develop more sustainable biological processes that avoid, for example, utilization of petroleum.
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Affiliation(s)
- Peter J F Henderson
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Claire Maher
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia
| | - Liam D H Elbourne
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park 5042, South Australia, Australia
| | - Ian T Paulsen
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Karl A Hassan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
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27
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Straub TJ, Chou WC, Manson AL, Schreiber HL, Walker BJ, Desjardins CA, Chapman SB, Kaspar KL, Kahsai OJ, Traylor E, Dodson KW, Hullar MAJ, Hultgren SJ, Khoo C, Earl AM. Limited effects of long-term daily cranberry consumption on the gut microbiome in a placebo-controlled study of women with recurrent urinary tract infections. BMC Microbiol 2021; 21:53. [PMID: 33596852 PMCID: PMC7890861 DOI: 10.1186/s12866-021-02106-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/28/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Urinary tract infections (UTIs) affect 15 million women each year in the United States, with > 20% experiencing frequent recurrent UTIs. A recent placebo-controlled clinical trial found a 39% reduction in UTI symptoms among recurrent UTI sufferers who consumed a daily cranberry beverage for 24 weeks. Using metagenomic sequencing of stool from a subset of these trial participants, we assessed the impact of cranberry consumption on the gut microbiota, a reservoir for UTI-causing pathogens such as Escherichia coli, which causes > 80% of UTIs. RESULTS The overall taxonomic composition, community diversity, carriage of functional pathways and gene families, and relative abundances of the vast majority of observed bacterial taxa, including E. coli, were not changed significantly by cranberry consumption. However, one unnamed Flavonifractor species (OTU41), which represented ≤1% of the overall metagenome, was significantly less abundant in cranberry consumers compared to placebo at trial completion. Given Flavonifractor's association with negative human health effects, we sought to determine OTU41 characteristic genes that may explain its differential abundance and/or relationship to key host functions. Using comparative genomic and metagenomic techniques, we identified genes in OTU41 related to transport and metabolism of various compounds, including tryptophan and cobalamin, which have been shown to play roles in host-microbe interactions. CONCLUSION While our results indicated that cranberry juice consumption had little impact on global measures of the microbiome, we found one unnamed Flavonifractor species differed significantly between study arms. This suggests further studies are needed to assess the role of cranberry consumption and Flavonifractor in health and wellbeing in the context of recurrent UTI. TRIAL REGISTRATION Clinical trial registration number: ClinicalTrials.gov NCT01776021 .
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Affiliation(s)
- Timothy J Straub
- Infectious Disease & Microbiome Program, Broad Institute, 415 Main Street, Cambridge, MA, 02142, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Wen-Chi Chou
- Infectious Disease & Microbiome Program, Broad Institute, 415 Main Street, Cambridge, MA, 02142, USA
| | - Abigail L Manson
- Infectious Disease & Microbiome Program, Broad Institute, 415 Main Street, Cambridge, MA, 02142, USA
| | - Henry L Schreiber
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Center for Women's Infectious Disease Research, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Bruce J Walker
- Infectious Disease & Microbiome Program, Broad Institute, 415 Main Street, Cambridge, MA, 02142, USA
| | - Christopher A Desjardins
- Infectious Disease & Microbiome Program, Broad Institute, 415 Main Street, Cambridge, MA, 02142, USA
| | - Sinéad B Chapman
- Infectious Disease & Microbiome Program, Broad Institute, 415 Main Street, Cambridge, MA, 02142, USA
| | | | - Orsalem J Kahsai
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Elizabeth Traylor
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Karen W Dodson
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Center for Women's Infectious Disease Research, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Meredith A J Hullar
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Scott J Hultgren
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Center for Women's Infectious Disease Research, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | | | - Ashlee M Earl
- Infectious Disease & Microbiome Program, Broad Institute, 415 Main Street, Cambridge, MA, 02142, USA.
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Turner JM, Connolly KL, Aberman KE, Fonseca JC, Singh A, Jerse AE, Nicholas RA, Davies C. Molecular Features of Cephalosporins Important for Activity against Antimicrobial-Resistant Neisseria gonorrhoeae. ACS Infect Dis 2021; 7:293-308. [PMID: 33533239 PMCID: PMC9847585 DOI: 10.1021/acsinfecdis.0c00400] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The increasing prevalence of Neisseria gonorrhoeae strains exhibiting decreased susceptibility to extended-spectrum cephalosporins (ESCs) presents a challenge for the successful treatment of gonorrhea infections. To address this challenge, we evaluated a panel of 23 cephalosporins against penicillin-binding protein 2 (PBP2) from the ESC-resistant (ESCR) N. gonorrhoeae strain H041 to determine which molecular features are important for antimicrobial activity. Structure-activity relationships (SARs) developed from acylation rate constants against PBP2 and antimicrobial susceptibilities against the H041 strain of N. gonorrhoeae, and interpreted against docking models, reveal that cephalosporins possessing large, lipophilic R1 side chains and electronegative R2 side chains with planar groups are associated with higher acylation rates against PBP2, but also that these same amphipathic features can lower antimicrobial activity. Based on these studies, we tested cefoperazone, one of the most effective ESCs for targeting PBP2, in the female mouse model infected with H041 and showed that it was equally or more effective than ceftriaxone or gentamicin for clearing infections. Taken together, our results reveal that two U.S. Food and Drug Administration (FDA)-approved agents (cefoperazone, ceftaroline) and one FDA-qualified infectious disease product (ceftobiprole) have potential as first-line treatments for gonorrhea and provide a framework for the future design of cephalosporins with improved activity against ESC-resistant N. gonorrhoeae.
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Affiliation(s)
- Jonathan M. Turner
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kristie L. Connolly
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814
| | - Kate E. Aberman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Joseph C. Fonseca
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Avinash Singh
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Ann E. Jerse
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814
| | - Robert A. Nicholas
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599,Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Christopher Davies
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425,Corresponding author: Department of Biochemistry & Molecular Biology, University of South Alabama, 5795 USA Drive North, Mobile, AL 36688. Tel +1 (651) 460-6659;
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29
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Lim KYL, Mullally CA, Haese EC, Kibble EA, McCluskey NR, Mikucki EC, Thai VC, Stubbs KA, Sarkar-Tyson M, Kahler CM. Anti-Virulence Therapeutic Approaches for Neisseria gonorrhoeae. Antibiotics (Basel) 2021; 10:antibiotics10020103. [PMID: 33494538 PMCID: PMC7911339 DOI: 10.3390/antibiotics10020103] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 01/15/2023] Open
Abstract
While antimicrobial resistance (AMR) is seen in both Neisseria gonorrhoeae and Neisseria meningitidis, the former has become resistant to commonly available over-the-counter antibiotic treatments. It is imperative then to develop new therapies that combat current AMR isolates whilst also circumventing the pathways leading to the development of AMR. This review highlights the growing research interest in developing anti-virulence therapies (AVTs) which are directed towards inhibiting virulence factors to prevent infection. By targeting virulence factors that are not essential for gonococcal survival, it is hypothesized that this will impart a smaller selective pressure for the emergence of resistance in the pathogen and in the microbiome, thus avoiding AMR development to the anti-infective. This review summates the current basis of numerous anti-virulence strategies being explored for N. gonorrhoeae.
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Affiliation(s)
- Katherine Y. L. Lim
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Christopher A. Mullally
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Ethan C. Haese
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Emily A. Kibble
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Nicolie R. McCluskey
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Edward C. Mikucki
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Van C. Thai
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Keith A. Stubbs
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia;
| | - Mitali Sarkar-Tyson
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Charlene M. Kahler
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- Correspondence:
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Neisseria meningitidis Urethritis Outbreak Isolates Express a Novel Factor H Binding Protein Variant That Is a Potential Target of Group B-Directed Meningococcal (MenB) Vaccines. Infect Immun 2020; 88:IAI.00462-20. [PMID: 32958529 DOI: 10.1128/iai.00462-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Abstract
Factor H binding protein (FHbp) is an important Neisseria meningitidis virulence factor that binds a negative regulator of the alternative complement pathway, human factor H (FH). Binding of FH increases meningococcal resistance to complement-mediated killing. FHbp also is reported to prevent interaction of the antimicrobial peptide (AMP) LL-37 with the meningococcal surface and meningococcal killing. FHbp is a target of two licensed group B-directed meningococcal (MenB) vaccines. We found a new FHbp variant, peptide allele identification no. 896 (ID 896), was highly expressed by an emerging meningococcal pathotype, the nonencapsulated urethritis clade (US_NmUC). This clade has been responsible for outbreaks of urethritis in multiple U.S. cities since 2015, other mucosal infections, and cases of invasive meningococcal disease. FHbp ID 896 is a member of the variant group 1 (subfamily B), bound protective anti-FHbp monoclonal antibodies, bound high levels of human FH, and enhanced the resistance of the clade to complement-mediated killing in low levels of human complement likely present at human mucosal surfaces. Interestingly, expression of FHbp ID 896 resulted in augmented killing of the clade by LL-37. FHbp ID 896 of the clade was recognized by antibodies elicited by FHbp in MenB vaccines.
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31
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Gao L, Wang Z, van der Veen S. Gonococcal Adaptation to Palmitic Acid Through farAB Expression and FadD Activity Mutations Increases In Vivo Fitness in a Murine Genital Tract Infection Model. J Infect Dis 2020; 224:141-150. [PMID: 33170275 DOI: 10.1093/infdis/jiaa701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/04/2020] [Indexed: 12/15/2022] Open
Abstract
Neisseria gonorrhoeae is a bacterial pathogen that colonizes mucosal epithelia that are rich in antimicrobial molecules such as long-chain fatty acids. Here we studied the mechanisms involved in palmitic acid resistance and their impact on in vivo biological fitness in a murine genital tract infection model. A stable palmitic acid-resistant derivative was obtained by serial passage with incremental palmitic acid concentrations. This derivative outcompeted its parent strain for colonization and survival in the murine infection model. Subsequent whole-genome sequencing resulted in the identification of the 3 resistance-related SNPs ihfAC5T, fadDC772T, and farAG-52T (promoter) that were verified for resistance against palmitic acid. Subsequent characterization of the associated resistance determinants showed that ihfAC5T and farAG-52T induced gene expression of the FarAB efflux pump, whereas fadDC772T increased the maximum enzyme activity of the FadD long-chain fatty acid-coenzyme A ligase. Our results highlight the mechanisms involved in gonococcal adaptation to the murine host environment.
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Affiliation(s)
- Lingyu Gao
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Zhemin Wang
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Stijn van der Veen
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China.,Department of Dermatology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China.,State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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32
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Liu Y, Shi J, Tong Z, Jia Y, Yang B, Wang Z. The revitalization of antimicrobial peptides in the resistance era. Pharmacol Res 2020; 163:105276. [PMID: 33161137 DOI: 10.1016/j.phrs.2020.105276] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 01/14/2023]
Abstract
The antibiotic resistance crisis is becoming incredibly thorny due to the indiscriminate employment of antibiotics in agriculture and aquaculture, such as growth promoters, and the emergence of bacteria that are capable of enduring antibiotic treatment in an endless stream. Hence, to reverse this situation, vigorous efforts should be made in the process of identifying other alternative strategies with a lower frequency of resistance. Antimicrobial peptides (AMPs), originated from host defense peptides, are generally produced by a variety of organisms as defensive weapons to protect the host from other pathogenic bacteria. The unique ability of AMPs to control bacterial infections, as well as low propensity to acquire resistance, provides the basis for it to become one of the promising antibacterial substances. Herein, we present new insights into the biological functions, structural properties, distinct mechanisms of action of AMPs and their resistance determinants. Besides, we separately discuss natural and synthetic AMPs, including their source, screening pathway and antibacterial activity. Lastly, challenges and perspectives to identify novel potent AMPs are highlighted, which will expand our understanding of the chemical space of antimicrobials and provide a pipeline for discovering the next-generation of AMPs.
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Affiliation(s)
- Yuan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China; Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, China.
| | - Jingru Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Ziwen Tong
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Yuqian Jia
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Bingqing Yang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China
| | - Zhiqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China.
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Honeycutt JD, Wenner N, Li Y, Brewer SM, Massis LM, Brubaker SW, Chairatana P, Owen SV, Canals R, Hinton JCD, Monack DM. Genetic variation in the MacAB-TolC efflux pump influences pathogenesis of invasive Salmonella isolates from Africa. PLoS Pathog 2020; 16:e1008763. [PMID: 32834002 PMCID: PMC7446830 DOI: 10.1371/journal.ppat.1008763] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/30/2020] [Indexed: 01/23/2023] Open
Abstract
The various sub-species of Salmonella enterica cause a range of disease in human hosts. The human-adapted Salmonella enterica serovar Typhi enters the gastrointestinal tract and invades systemic sites to cause enteric (typhoid) fever. In contrast, most non-typhoidal serovars of Salmonella are primarily restricted to gut tissues. Across Africa, invasive non-typhoidal Salmonella (iNTS) have emerged with an ability to spread beyond the gastrointestinal tract and cause systemic bloodstream infections with increased morbidity and mortality. To investigate this evolution in pathogenesis, we compared the genomes of African iNTS isolates with other Salmonella enterica serovar Typhimurium and identified several macA and macB gene variants unique to African iNTS. MacAB forms a tripartite efflux pump with TolC and is implicated in Salmonella pathogenesis. We show that macAB transcription is upregulated during macrophage infection and after antimicrobial peptide exposure, with macAB transcription being supported by the PhoP/Q two-component system. Constitutive expression of macAB improves survival of Salmonella in the presence of the antimicrobial peptide C18G. Furthermore, these macAB variants affect replication in macrophages and influence fitness during colonization of the murine gastrointestinal tract. Importantly, the infection outcome resulting from these macAB variants depends upon both the Salmonella Typhimurium genetic background and the host gene Nramp1, an important determinant of innate resistance to intracellular bacterial infection. The variations we have identified in the MacAB-TolC efflux pump in African iNTS may reflect evolution within human host populations that are compromised in their ability to clear intracellular Salmonella infections.
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Affiliation(s)
- Jared D. Honeycutt
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Nicolas Wenner
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Yan Li
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Susan M. Brewer
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Liliana M. Massis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sky W. Brubaker
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Phoom Chairatana
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Siân V. Owen
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Rocío Canals
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Jay C. D. Hinton
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Denise M. Monack
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
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Russell MW, Gray-Owen SD, Jerse AE. Editorial: Immunity to Neisseria gonorrhoeae. Front Immunol 2020; 11:1375. [PMID: 32714334 PMCID: PMC7343768 DOI: 10.3389/fimmu.2020.01375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 05/29/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael W. Russell
- Department of Microbiology and Immunology, University at Buffalo, Buffalo, NY, United States
| | - Scott D. Gray-Owen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Ann E. Jerse
- Department of Microbiology and Immunology, F. Edward Hebert School of Medicine, Uniformed Services University, Bethesda, MD, United States
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Anti-bacterial activity of inorganic nanomaterials and their antimicrobial peptide conjugates against resistant and non-resistant pathogens. Int J Pharm 2020; 586:119531. [PMID: 32540348 DOI: 10.1016/j.ijpharm.2020.119531] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 06/04/2020] [Accepted: 06/06/2020] [Indexed: 12/20/2022]
Abstract
This review details the antimicrobial applications of inorganic nanomaterials of mostly metallic form, and the augmentation of activity by surface conjugation of peptide ligands. The review is subdivided into three main sections, of which the first describes the antimicrobial activity of inorganic nanomaterials against gram-positive, gram-negative and multidrug-resistant bacterial strains. The second section highlights the range of antimicrobial peptides and the drug resistance strategies employed by bacterial species to counter lethality. The final part discusses the role of antimicrobial peptide-decorated inorganic nanomaterials in the fight against bacterial strains that show resistance. General strategies for the preparation of antimicrobial peptides and their conjugation to nanomaterials are discussed, emphasizing the use of elemental and metallic oxide nanomaterials. Importantly, the permeation of antimicrobial peptides through the bacterial membrane is shown to aid the delivery of nanomaterials into bacterial cells. By judicious use of targeting ligands, the nanomaterial becomes able to differentiate between bacterial and mammalian cells and, thus, reduce side effects. Moreover, peptide conjugation to the surface of a nanomaterial will alter surface chemistry in ways that lead to reduction in toxicity and improvements in biocompatibility.
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The Efflux Pump MexXY/OprM Contributes to the Tolerance and Acquired Resistance of Pseudomonas aeruginosa to Colistin. Antimicrob Agents Chemother 2020; 64:AAC.02033-19. [PMID: 31964794 DOI: 10.1128/aac.02033-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/13/2020] [Indexed: 12/29/2022] Open
Abstract
The intrinsic resistance of Pseudomonas aeruginosa to polymyxins in part relies on the addition of 4-amino-4-deoxy-l-arabinose (Ara4N) molecules to the lipid A of lipopolysaccharide (LPS), through induction of operon arnBCADTEF-ugd (arn) expression. As demonstrated previously, at least three two-component regulatory systems (PmrAB, ParRS, and CprRS) are able to upregulate this operon when bacteria are exposed to colistin. In the present study, gene deletion experiments with the bioluminescent strain PAO1::lux showed that ParRS is a key element in the tolerance of P. aeruginosa to this last-resort antibiotic (i.e., resistance to early drug killing). Other loci of the ParR regulon, such as those encoding the efflux proteins MexXY (mexXY), the polyamine biosynthetic pathway PA4773-PA4774-PA4775, and Ara4N LPS modification process (arnBCADTEF-ugd), also contribute to the bacterial tolerance in an intricate way with ParRS. Furthermore, we found that both stable upregulation of the arn operon and drug-induced ParRS-dependent overexpression of the mexXY genes accounted for the elevated resistance of pmrB mutants to colistin. Deletion of the mexXY genes in a constitutively activated ParR mutant of PAO1 was associated with significantly increased expression of the genes arnA, PA4773, and pmrA in the absence of colistin exposure, thereby highlighting a functional link between the MexXY/OprM pump, the PA4773-PA4774-PA4775 pathway, and Ara4N-based modification of LPS. The role played by MexXY/OprM in the adaptation of P. aeruginosa to polymyxins opens new perspectives for restoring the susceptibility of resistant mutants through the use of efflux inhibitors.
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Kapach G, Nuri R, Schmidt C, Danin A, Ferrera S, Savidor A, Gerlach RG, Shai Y. Loss of the Periplasmic Chaperone Skp and Mutations in the Efflux Pump AcrAB-TolC Play a Role in Acquired Resistance to Antimicrobial Peptides in Salmonella typhimurium. Front Microbiol 2020; 11:189. [PMID: 32210923 PMCID: PMC7075815 DOI: 10.3389/fmicb.2020.00189] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/27/2020] [Indexed: 01/01/2023] Open
Abstract
Bacterial resistance to antibiotics is a major concern worldwide, leading to an extensive search for alternative drugs. Promising candidates are antimicrobial peptides (AMPs), innate immunity molecules, shown to be highly efficient against multidrug resistant bacteria. Therefore, it is essential to study bacterial resistance mechanisms against them. For that purpose, we used experimental evolution, and isolated a Salmonella enterica serovar typhimurium-resistant line to the AMP 4DK5L7. This AMP displayed promising features including widespread activity against Gram-negative bacteria and protection from proteolytic degradation. However, the resistance that evolved in the isolated strain was particularly high. Whole genome sequencing revealed that five spontaneous mutations had evolved. Of these, three are novel in the context of acquired AMP resistance. Two mutations are related to the AcrAB-TolC multidrug efflux pump. One occurred in AcrB, the substrate-binding domain of the system, and the second in RamR, a transcriptional regulator of the system. Together, the mutations increased the minimal inhibitory concentration (MIC) by twofold toward this AMP. Moreover, the mutation in AcrB induced hypersusceptibility toward ampicillin and colistin. The last mutation occurred in Skp, a periplasmic chaperone that participates in the biogenesis of outer membrane proteins (OMPs). This mutation increased the MIC by twofold to 4DK5L7 and by fourfold to another AMP, seg5D. Proteomic analysis revealed that the mutation abolished Skp expression, reduced OMP abundance, and increased DegP levels. DegP, a protease that was reported to have an additional chaperone activity, escorts OMPs through the periplasm along with Skp, but is also associated with AMP resistance. In conclusion, our data demonstrate that both loss of Skp and manipulation of the AcrAB-TolC system are alternative strategies of AMP acquired resistance in Salmonella typhimurium and might represent a common mechanism in other Gram-negative bacteria.
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Affiliation(s)
- Gal Kapach
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Reut Nuri
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | | | - Adi Danin
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shir Ferrera
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Alon Savidor
- de Botton Institute for Protein Profiling, The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Roman G Gerlach
- Project Group 5, Robert Koch Institute, Wernigerode, Germany
| | - Yechiel Shai
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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Duperthuy M. Antimicrobial Peptides: Virulence and Resistance Modulation in Gram-Negative Bacteria. Microorganisms 2020; 8:microorganisms8020280. [PMID: 32092866 PMCID: PMC7074834 DOI: 10.3390/microorganisms8020280] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 02/03/2023] Open
Abstract
Growing resistance to antibiotics is one of the biggest threats to human health. One of the possibilities to overcome this resistance is to use and develop alternative molecules such as antimicrobial peptides (AMPs). However, an increasing number of studies have shown that bacterial resistance to AMPs does exist. Since AMPs are immunity molecules, it is important to ensure that their potential therapeutic use is not harmful in the long term. Recently, several studies have focused on the adaptation of Gram-negative bacteria to subinhibitory concentrations of AMPs. Such concentrations are commonly found in vivo and in the environment. It is therefore necessary to understand how bacteria detect and respond to low concentrations of AMPs. This review focuses on recent findings regarding the impact of subinhibitory concentrations of AMPs on the modulation of virulence and resistance in Gram-negative bacteria.
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Affiliation(s)
- Marylise Duperthuy
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Succ. Centre-ville, Montréal, QC H3C 3J7, Canada
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Multidrug Resistance in Neisseria gonorrhoeae: Identification of Functionally Important Residues in the MtrD Efflux Protein. mBio 2019; 10:mBio.02277-19. [PMID: 31744915 PMCID: PMC6867893 DOI: 10.1128/mbio.02277-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
With over 78 million new infections globally each year, gonorrhea remains a frustratingly common infection. Continuous development and spread of antimicrobial-resistant strains of Neisseria gonorrhoeae, the causative agent of gonorrhea, have posed a serious threat to public health. One of the mechanisms in N. gonorrhoeae involved in resistance to multiple drugs is performed by the MtrD multidrug resistance efflux pump. This study demonstrated that the MtrD pump has a broader substrate specificity than previously proposed and identified a cluster of residues important for drug binding and translocation. Additionally, a permeation pathway for the MtrD substrate progesterone actively moving through the protein was determined, revealing key interactions within the putative MtrD drug binding pockets. Identification of functionally important residues and substrate-protein interactions of the MtrD protein is crucial to develop future strategies for the treatment of multidrug-resistant gonorrhea. A key mechanism that Neisseria gonorrhoeae uses to achieve multidrug resistance is the expulsion of structurally different antimicrobials by the MtrD multidrug efflux protein. MtrD resembles the homologous Escherichia coli AcrB efflux protein with several common structural features, including an open cleft containing putative access and deep binding pockets proposed to interact with substrates. A highly discriminating N. gonorrhoeae strain, with the MtrD and NorM multidrug efflux pumps inactivated, was constructed and used to confirm and extend the substrate profile of MtrD to include 14 new compounds. The structural basis of substrate interactions with MtrD was interrogated by a combination of long-timescale molecular dynamics simulations and docking studies together with site-directed mutagenesis of selected residues. Of the MtrD mutants generated, only one (S611A) retained a wild-type (WT) resistance profile, while others (F136A, F176A, I605A, F610A, F612C, and F623C) showed reduced resistance to different antimicrobial compounds. Docking studies of eight MtrD substrates confirmed that many of the mutated residues play important nonspecific roles in binding to these substrates. Long-timescale molecular dynamics simulations of MtrD with its substrate progesterone showed the spontaneous binding of the substrate to the access pocket of the binding cleft and its subsequent penetration into the deep binding pocket, allowing the permeation pathway for a substrate through this important resistance mechanism to be identified. These findings provide a detailed picture of the interaction of MtrD with substrates that can be used as a basis for rational antibiotic and inhibitor design.
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Abdi M, Mirkalantari S, Amirmozafari N. Bacterial resistance to antimicrobial peptides. J Pept Sci 2019; 25:e3210. [DOI: 10.1002/psc.3210] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/04/2019] [Accepted: 07/21/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Milad Abdi
- Student Research Committee, Faculty of MedicineIran University of Medical Sciences Tehran Iran
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
| | - Shiva Mirkalantari
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
| | - Nour Amirmozafari
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
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Chen S, Connolly KL, Rouquette-Loughlin C, D'Andrea A, Jerse AE, Shafer WM. Could Dampening Expression of the Neisseria gonorrhoeae mtrCDE-Encoded Efflux Pump Be a Strategy To Preserve Currently or Resurrect Formerly Used Antibiotics To Treat Gonorrhea? mBio 2019; 10:e01576-19. [PMID: 31409679 PMCID: PMC6692510 DOI: 10.1128/mbio.01576-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 07/15/2019] [Indexed: 12/29/2022] Open
Abstract
Neisseria gonorrhoeae has developed resistance to every antibiotic introduced for treatment of gonorrhea since 1938, and concern now exists that gonorrheal infections may become refractory to all available antibiotics approved for therapy. The current recommended dual antibiotic treatment regimen of ceftriaxone (CRO) and azithromycin (AZM) is threatened with the emergence of gonococcal strains displaying resistance to one or both of these antibiotics. Non-beta-lactamase resistance to penicillin and third-generation cephalosporins, as well as low-level AZM resistance expressed by gonococci, requires overexpression of the mtrCDE-encoded efflux pump, which in wild-type (WT) strains is subject to transcriptional repression by MtrR. Since earlier studies showed that loss of MtrCDE renders gonococci hypersusceptible to beta-lactams and macrolides, we hypothesized that transcriptional dampening of mtrCDE would render an otherwise resistant strain susceptible to these antibiotics as assessed by antibiotic susceptibility testing and during experimental infection. In order to test this hypothesis, we ectopically expressed a WT copy of the mtrR gene, which encodes the repressor of the mtrCDE efflux pump operon, in N. gonorrhoeae strain H041, the first reported gonococcal strain to cause a third-generation-cephalosporin-resistant infection. We now report that MtrR production can repress the expression of mtrCDE, increase antimicrobial susceptibility in vitro, and enhance beta-lactam efficacy in eliminating gonococci as assessed in a female mouse model of lower genital tract infection. We propose that strategies that target the MtrCDE efflux pump should be considered to counteract the increasing problem of antibiotic-resistant gonococci.IMPORTANCE The emergence of gonococcal strains resistant to past or currently used antibiotics is a global public health concern, given the estimated 78 million infections that occur annually. The dearth of new antibiotics to treat gonorrhea demands that alternative curative strategies be considered to counteract antibiotic resistance expressed by gonococci. Herein, we show that decreased expression of a drug efflux pump that participates in gonococcal resistance to antibiotics can increase gonococcal susceptibility to beta-lactams and macrolides under laboratory conditions, as well as improve antibiotic-mediated clearance of gonococci from the genital tract of experimentally infected female mice.
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Affiliation(s)
- Shaochun Chen
- Department of Microbiology and Immunology and the Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
- Laboratories of Bacterial Pathogenesis, VA Medical Center, Decatur, Georgia, USA
- National Center for STD Control, Chinese Center for Disease Control and Prevention, Nanjing, China
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
| | - Kristie L Connolly
- Department of Microbiology and Immunology, F. Edward Hebert School of Medicine, Uniformed Services University, Bethesda, Maryland, USA
| | - Corinne Rouquette-Loughlin
- Department of Microbiology and Immunology and the Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
- Laboratories of Bacterial Pathogenesis, VA Medical Center, Decatur, Georgia, USA
| | - Alexander D'Andrea
- Department of Microbiology and Immunology and the Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
- Laboratories of Bacterial Pathogenesis, VA Medical Center, Decatur, Georgia, USA
| | - Ann E Jerse
- Department of Microbiology and Immunology, F. Edward Hebert School of Medicine, Uniformed Services University, Bethesda, Maryland, USA
| | - William M Shafer
- Department of Microbiology and Immunology and the Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
- Laboratories of Bacterial Pathogenesis, VA Medical Center, Decatur, Georgia, USA
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Kuppusamy R, Willcox M, Black DS, Kumar N. Short Cationic Peptidomimetic Antimicrobials. Antibiotics (Basel) 2019; 8:antibiotics8020044. [PMID: 31003540 PMCID: PMC6628222 DOI: 10.3390/antibiotics8020044] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 12/28/2022] Open
Abstract
The rapid growth of antimicrobial resistance against several frontline antibiotics has encouraged scientists worldwide to develop new alternatives with unique mechanisms of action. Antimicrobial peptides (AMPs) have attracted considerable interest due to their rapid killing and broad-spectrum activity. Peptidomimetics overcome some of the obstacles of AMPs such as high cost of synthesis, short half-life in vivo due to their susceptibility to proteolytic degradation, and issues with toxicity. This review will examine the development of short cationic peptidomimetics as antimicrobials.
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Affiliation(s)
- Rajesh Kuppusamy
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Mark Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, NSW 2052, Australia.
| | - David StC Black
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Naresh Kumar
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
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Ciumac D, Gong H, Hu X, Lu JR. Membrane targeting cationic antimicrobial peptides. J Colloid Interface Sci 2019; 537:163-185. [DOI: 10.1016/j.jcis.2018.10.103] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/29/2018] [Accepted: 10/30/2018] [Indexed: 01/13/2023]
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Abstract
Gallstone disease is caused by multiple pathogenic factors and is common worldwide. Most studies have focused on the significance of the biliary microbiome in gallstone pathogenesis. Areas covered: In this study, the epidemiology of gallstone diseases and the existence, composition, origin, and mechanisms of the biliary microbiota were reviewed. Mechanisms involved in promoting the formation of different types of gallstones were also emphasized. The antibiotic susceptibility of the biliary microbiota is briefly discussed because it may guide clinical strategies. Expert commentary: The biliary microbiome facilitates the formation of brown pigment stones. Although glycoprotein (mucin) may be pivotal for many promoting substances to coagulate and integrate relevant components, new mechanisms involving prostaglandins, oxysterols, oxygen free radicals, and lipopolysaccharides have been discovered. Furthermore, specific bacterial species such as Helicobacter and Salmonella are involved in the pathogenesis of cholesterol gallstones. Recently, metabolomics of the biliary microbiome has been used to determine the detailed mechanisms that promote gallstone formation. Previously, the bacterial effects involved in the pathogenesis of brown pigment stones have not been analyzed in detail. Whether the administration of antibiotics is related to prophylaxis for gallstone formation and gallstone-associated infections remains unclear.
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Affiliation(s)
- Yining Wang
- a Department of Gastroenterology , The First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi , China.,b Joint Programme of Nanchang University and Queen Mary University of London , Nanchang , China
| | - Miao Qi
- a Department of Gastroenterology , The First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi , China.,b Joint Programme of Nanchang University and Queen Mary University of London , Nanchang , China
| | - Cheng Qin
- a Department of Gastroenterology , The First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi , China.,b Joint Programme of Nanchang University and Queen Mary University of London , Nanchang , China
| | - Junbo Hong
- a Department of Gastroenterology , The First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi , China
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Handing JW, Ragland SA, Bharathan UV, Criss AK. The MtrCDE Efflux Pump Contributes to Survival of Neisseria gonorrhoeae From Human Neutrophils and Their Antimicrobial Components. Front Microbiol 2018; 9:2688. [PMID: 30515136 PMCID: PMC6256084 DOI: 10.3389/fmicb.2018.02688] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/22/2018] [Indexed: 12/24/2022] Open
Abstract
The mucosal inflammatory response to Neisseria gonorrhoeae (Gc) is characterized by recruitment of neutrophils to the site of infection. Gc survives exposure to neutrophils by limiting the ability of neutrophils to make antimicrobial products and by expressing factors that defend against these products. The multiple transferable resistance (Mtr) system is a tripartite efflux pump, comprised of the inner membrane MtrD, the periplasmic attachment protein MtrC, and the outer membrane channel MtrE. Gc MtrCDE exports a diverse array of substrates, including certain detergents, dyes, antibiotics, and host-derived antimicrobial peptides. Here we report that MtrCDE contributes to the survival of Gc after exposure to adherent, chemokine-treated primary human neutrophils, specifically in the extracellular milieu. MtrCDE enhanced survival of Gc in neutrophil extracellular traps and in the supernatant from neutrophils that had undergone degranulation (granule exocytosis), a process that releases antimicrobial proteins into the extracellular milieu. The extent of degranulation was unaltered in neutrophils exposed to parental or mtr mutant Gc. MtrCDE expression contributed to Gc defense against some neutrophil-derived antimicrobial peptides but not others. These findings demonstrate that the Mtr system contributes to Gc survival after neutrophil challenge, a key feature of the host immune response to acute gonorrhea.
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Affiliation(s)
- Jonathan W Handing
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States
| | - Stephanie A Ragland
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States
| | - Urmila V Bharathan
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States
| | - Alison K Criss
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States
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Tzeng YL, Berman Z, Toh E, Bazan JA, Turner AN, Retchless AC, Wang X, Nelson DE, Stephens DS. Heteroresistance to the model antimicrobial peptide polymyxin B in the emerging Neisseria meningitidis lineage 11.2 urethritis clade: mutations in the pilMNOPQ operon. Mol Microbiol 2018; 111:254-268. [PMID: 30338585 DOI: 10.1111/mmi.14153] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2018] [Indexed: 02/02/2023]
Abstract
Clusters of Neisseria meningitidis (Nm) urethritis among primarily heterosexual males in multiple US cities have been attributed to a unique non-encapsulated meningococcal clade (the US Nm urethritis clade, US_NmUC) within the hypervirulent clonal complex 11. Resistance to antimicrobial peptides (AMPs) is a key feature of urogenital pathogenesis of the closely related species, Neisseria gonorrhoeae. The US_NmUC isolates were found to be highly resistant to the model AMP, polymyxin B (PmB, MICs 64-256 µg ml-1 ). The isolates also demonstrated stable subpopulations of heteroresistant colonies that showed near total resistant to PmB (MICs 384-1024 µg ml-1 ) and colistin (MIC 256 µg ml-1 ) as well as enhanced LL-37 resistance. This is the first observation of heteroresistance in N. meningitidis. Consistent with previous findings, overall PmB resistance in US_NmUC isolates was due to active Mtr efflux and LptA-mediated lipid A modification. However, whole genome sequencing, variant analyses and directed mutagenesis revealed that the heteroresistance phenotypes and very high-level AMP resistance were the result of point mutations and IS1655 element movement in the pilMNOPQ operon, encoding the type IV pilin biogenesis apparatus. Cross-resistance to other classes of antibiotics was also observed in the heteroresistant colonies. High-level resistance to AMPs may contribute to the pathogenesis of US_NmUC.
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Affiliation(s)
- Yih-Ling Tzeng
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Zachary Berman
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Evelyn Toh
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jose A Bazan
- Division of Infectious Diseases, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, OH, 43210, USA.,Sexual Health Clinic, Columbus Public Health, Columbus, OH, 43210, USA
| | - Abigail Norris Turner
- Division of Infectious Diseases, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, OH, 43210, USA
| | - Adam C Retchless
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Xin Wang
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - David E Nelson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - David S Stephens
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, 30322, USA
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Subhadra B, Kim J, Kim DH, Woo K, Oh MH, Choi CH. Local Repressor AcrR Regulates AcrAB Efflux Pump Required for Biofilm Formation and Virulence in Acinetobacter nosocomialis. Front Cell Infect Microbiol 2018; 8:270. [PMID: 30131944 PMCID: PMC6090078 DOI: 10.3389/fcimb.2018.00270] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/19/2018] [Indexed: 12/28/2022] Open
Abstract
Multidrug efflux systems contribute to antimicrobial resistance and pathogenicity in bacteria. Here, we report the identification and characterization of a transcriptional regulator AcrR controlling the yet uncharacterized multidrug efflux pump, AcrAB in Acinetobacter nosocomialis. In silico analysis revealed that the homologs of AcrR and AcrAB are reported in the genomes of many other bacterial species. We confirmed that the genes encoding the AcrAB efflux pump, acrA and acrB forms a polycistronic operon which is under the control of acrR gene upstream of acrA. Bioinformatic analysis indicated the presence of AcrR binding motif in the promoter region of acrAB operon and the specific binding of AcrR was confirmed by electrophoretic mobility shift assay (EMSA). The EMSA data showed that AcrR binds to −89 bp upstream of the start codon of acrA. The mRNA expression analysis depicted that the expression of acrA and acrB genes are elevated in the deletion mutant compared to that in the wild type confirming that AcrR acts as a repressor of acrAB operon in A. nosocomialis. The deletion of acrR resulted in increased motility, biofilm/pellicle formation and invasion in A. nosocomialis. We further analyzed the role of AcrR in A. nosocomialis pathogenesis in vivo using murine model and it was shown that acrR mutant is highly virulent inducing severe infection in mouse leading to host death. In addition, the intracellular survival rate of acrR mutant was higher compared to that of wild type. Our data demonstrates that AcrR functions as an important regulator of AcrAB efflux pump and is associated with several phenotypes such as motility, biofilm/pellicle formation and pathogenesis in A. nosocomialis.
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Affiliation(s)
- Bindu Subhadra
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Jaeseok Kim
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Dong Ho Kim
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Kyungho Woo
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Man Hwan Oh
- Department of Nanobiomedical Science, Dankook University, Cheonan, South Korea
| | - Chul Hee Choi
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea
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cis- and trans-Acting Factors Influence Expression of the norM-Encoded Efflux Pump of Neisseria gonorrhoeae and Levels of Gonococcal Susceptibility to Substrate Antimicrobials. Antimicrob Agents Chemother 2018; 62:AAC.00821-18. [PMID: 29891604 DOI: 10.1128/aac.00821-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 06/05/2018] [Indexed: 11/20/2022] Open
Abstract
The gonococcal NorM efflux pump exports substrates with a cationic moiety, including quaternary ammonium compounds such as berberine (BE) and ethidium bromide (EB) as well as antibiotics such as ciprofloxacin and solithromycin. The norM gene is part of a four-gene operon that is transcribed from a promoter containing a polynucleotide tract of 6 or 7 thymidines (T's) between the -10 and -35 hexamers; the majority of gonococcal strains analyzed in this study contained a T-6 sequence. Primer extension analysis showed that regardless of the length of the poly(T) tract, the same transcriptional start site (TSS) was used for expression of norM Interestingly, the T-6 tract correlated with a higher level of both norM expression and gonococcal resistance to NorM substrates BE and EB. Analysis of expression of genes downstream of norM showed that the product of the tetR-like gene has the capacity to activate expression of norM as well as murB, which encodes an acetylenolpyroylglucosamine reductase predicted to be involved in the early steps of peptidoglycan synthesis. Moreover, loss of the TetR-like transcriptional regulator modestly increased gonococcal susceptibility to NorM substrates EB and BE. We conclude that both cis- and trans-acting regulatory systems can regulate expression of the norM operon and influence levels of gonococcal susceptibility to antimicrobials exported by NorM.
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Transcriptome Analysis of Neisseria gonorrhoeae during Natural Infection Reveals Differential Expression of Antibiotic Resistance Determinants between Men and Women. mSphere 2018; 3:3/3/e00312-18. [PMID: 29950382 PMCID: PMC6021601 DOI: 10.1128/mspheredirect.00312-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 06/06/2018] [Indexed: 11/20/2022] Open
Abstract
Recent emergence of antimicrobial resistance of Neisseria gonorrhoeae worldwide has resulted in limited therapeutic choices for treatment of infections caused by this organism. We performed global transcriptomic analysis of N. gonorrhoeae in subjects with gonorrhea who attended a Nanjing, China, sexually transmitted infection (STI) clinic, where antimicrobial resistance of N. gonorrhoeae is high and increasing. We found that N. gonorrhoeae transcriptional responses to infection differed in genital specimens taken from men and women, particularly antibiotic resistance gene expression, which was increased in men. These sex-specific findings may provide a new approach to guide therapeutic interventions and preventive measures that are also sex specific while providing additional insight to address antimicrobial resistance of N. gonorrhoeae. Neisseria gonorrhoeae is a bacterial pathogen responsible for the sexually transmitted infection gonorrhea. Emergence of antimicrobial resistance (AMR) of N. gonorrhoeae worldwide has resulted in limited therapeutic choices for this infection. Men who seek treatment often have symptomatic urethritis; in contrast, gonococcal cervicitis in women is usually minimally symptomatic, but may progress to pelvic inflammatory disease. Previously, we reported the first analysis of gonococcal transcriptome expression determined in secretions from women with cervical infection. Here, we defined gonococcal global transcriptional responses in urethral specimens from men with symptomatic urethritis and compared these with transcriptional responses in specimens obtained from women with cervical infections and in vitro-grown N. gonorrhoeae isolates. This is the first comprehensive comparison of gonococcal gene expression in infected men and women. RNA sequencing analysis revealed that 9.4% of gonococcal genes showed increased expression exclusively in men and included genes involved in host immune cell interactions, while 4.3% showed increased expression exclusively in women and included phage-associated genes. Infected men and women displayed comparable antibiotic-resistant genotypes and in vitro phenotypes, but a 4-fold higher expression of the Mtr efflux pump-related genes was observed in men. These results suggest that expression of AMR genes is programed genotypically and also driven by sex-specific environments. Collectively, our results indicate that distinct N. gonorrhoeae gene expression signatures are detected during genital infection in men and women. We propose that therapeutic strategies could target sex-specific differences in expression of antibiotic resistance genes. IMPORTANCE Recent emergence of antimicrobial resistance of Neisseria gonorrhoeae worldwide has resulted in limited therapeutic choices for treatment of infections caused by this organism. We performed global transcriptomic analysis of N. gonorrhoeae in subjects with gonorrhea who attended a Nanjing, China, sexually transmitted infection (STI) clinic, where antimicrobial resistance of N. gonorrhoeae is high and increasing. We found that N. gonorrhoeae transcriptional responses to infection differed in genital specimens taken from men and women, particularly antibiotic resistance gene expression, which was increased in men. These sex-specific findings may provide a new approach to guide therapeutic interventions and preventive measures that are also sex specific while providing additional insight to address antimicrobial resistance of N. gonorrhoeae.
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