scholarly journals Polyamines Can Increase Resistance of Neisseria gonorrhoeae to Mediators of the Innate Human Host Defense

2010 ◽  
Vol 78 (7) ◽  
pp. 3187-3195 ◽  
Author(s):  
Maira Goytia ◽  
William M. Shafer
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antimicrobial Peptides ◽  
Host Defense ◽  
Polymyxin B ◽  
Cellular Functions ◽  
Cationic Antimicrobial Peptides ◽  
Sexually Transmitted ◽  
Bacterial Surface ◽  
Bodily Fluids ◽  
Mucosal Surfaces

ABSTRACT Polyamines are biogenic polycationic molecules involved in key cellular functions. Extracellular polyamines found in bodily fluids or laboratory media can be imported by bacteria or bind to negatively charged bacterial surface structures, where they can impair binding of antimicrobials. We hypothesized that the presence of polyamines in fluids that bathe urogenital mucosal surfaces could alter the susceptibility of the sexually transmitted strict human pathogen Neisseria gonorrhoeae to mediators of the innate host defense. Herein we report that polyamines can significantly increase gonococcal resistance to two structurally diverse cationic antimicrobial peptides (polymyxin B and LL-37) but not to antibiotics that exert activity in the cytosol or periplasm (e.g., ciprofloxacin, spectinomycin, or penicillin). The capacity of polyamines to increase gonococcal resistance to cationic antimicrobial peptides was dose dependent, correlated with the degree of cationicity, independent of a polyamine transport system involving the polyamine permeases PotH and PotI, and was reversible. In addition, we found that polyamines increase gonococcal resistance to complement-mediated killing by normal human serum. We propose that polyamines in genital mucosal fluids may enhance gonococcal survival during infection by reducing bacterial susceptibility to host-derived antimicrobials that function in innate host defense.

A drug candidate for Alzheimer’s and Huntington’s disease, PBT2, can be repurposed to render Neisseria gonorrhoeae susceptible to natural cationic antimicrobial peptides

2021 ◽  
Author(s):  
Freda E -C Jen ◽  
Ibrahim M El-Deeb ◽  
Yaramah M Zalucki ◽  
Jennifer L Edwards ◽  
Mark J Walker ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antimicrobial Peptides ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Proteomic Analysis ◽  
Protein Misfolding ◽  
Membrane Integrity ◽  
Drug Candidate ◽  
Cationic Antimicrobial Peptides ◽  
Broth Microdilution Method

Abstract Background Neisseria gonorrhoeae is a Gram-negative bacterial pathogen that causes gonorrhoea. No vaccine is available to prevent gonorrhoea and the emergence of MDR N. gonorrhoeae strains represents an immediate public health threat. Objectives To evaluate whether PBT2/zinc may sensitize MDR N. gonorrhoeae to natural cationic antimicrobial peptides. Methods MDR strains that contain differing resistance mechanisms against numerous antibiotics were tested in MIC assays. MIC assays were performed using the broth microdilution method according to CLSI guidelines in a microtitre plate. Serially diluted LL-37 or PG-1 was tested in combination with a sub-inhibitory concentration of PBT2/zinc. Serially diluted tetracycline was also tested with sub-inhibitory concentrations of PBT2/zinc and LL-37. SWATH-MS proteomic analysis of N. gonorrhoeae treated with PBT2/zinc, LL-37 and/or tetracycline was performed to determine the mechanism(s) of N. gonorrhoeae susceptibility to antibiotics and peptides. Results Sub-inhibitory concentrations of LL-37 and PBT2/zinc synergized to render strain WHO-Z susceptible to tetracycline, whereas the killing effect of PG-1 and PBT2/zinc was additive. SWATH-MS proteomic analysis suggested that PBT2/zinc most likely leads to a loss of membrane integrity and increased protein misfolding and, in turn, results in bacterial death. Conclusions Here we show that PBT2, a candidate Alzheimer’s and Huntington’s disease drug, can be repurposed to render MDR N. gonorrhoeae more susceptible to the endogenous antimicrobial peptides LL-37 and PG-1. In the presence of LL-37, PBT2/zinc can synergize with tetracycline to restore tetracycline susceptibility to gonococci resistant to this antibiotic.

scholarly journals In VitroCross-Resistance to Daptomycin and Host Defense Cationic Antimicrobial Peptides in Clinical Methicillin-Resistant Staphylococcus aureus Isolates

2011 ◽  
Vol 55 (9) ◽  
pp. 4012-4018 ◽  
Author(s):  
Nagendra N. Mishra ◽  
James McKinnell ◽  
Michael R. Yeaman ◽  
Aileen Rubio ◽  
Cynthia C. Nast ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Membrane ◽  
Antimicrobial Peptides ◽  
Surface Charge ◽  
Host Defense ◽  
Cationic Antimicrobial Peptides ◽  
Methicillin Resistant ◽  
Membrane Order

ABSTRACTWe investigated the hypothesis that methicillin-resistantStaphylococcus aureus(MRSA) isolates developing reduced susceptibilities to daptomycin (DAP; a calcium-dependent molecule acting as a cationic antimicrobial peptide [CAP]) may also coevolve reducedin vitrosusceptibilities to host defense cationic antimicrobial peptides (HDPs). Ten isogenic pairs of clinical MRSA DAP-susceptible/DAP-resistant (DAPs/DAPr) strains were tested against two distinct HDPs differing in structure, mechanism of action, and origin (thrombin-induced platelet microbicidal proteins [tPMPs] and human neutrophil peptide-1 [hNP-1]) and one bacterium-derived CAP, polymyxin B (PMB). Seven of 10 DAPrstrains had point mutations in themprFlocus (with or withoutyycoperon mutations), while three DAPrstrains had neither mutation. Several phenotypic parameters previously associated with DAPrwere also examined: cell membrane order (fluidity), surface charge, and cell wall thickness profiles. Compared to the 10 DAPsparental strains, their respective DAPrstrains exhibited (i) significantly reduced susceptibility to killing by all three peptides (P< 0.05), (ii) increased cell membrane fluidity, and (iii) significantly thicker cell walls (P< 0.0001). There was no consistent pattern of surface charge profiles distinguishing DAPsand DAPrstrain pairs. Reducedin vitrosusceptibility to two HDPs and one bacterium-derived CAP tracked closely with DAPrin these 10 recent MRSA clinical isolates. These results suggest that adaptive mechanisms involved in the evolution of DAPralso provide MRSA with enhanced survivability against HDPs. Such adaptations appear to correlate with MRSA variations in cell membrane order and cell wall structure. DAPrstrains with or without mutations in themprFlocus demonstrated significant cross-resistance profiles to these unrelated CAPs.

scholarly journals MetQ of Neisseria gonorrhoeae Is a Surface-Expressed Antigen That Elicits Bactericidal and Functional Blocking Antibodies

2016 ◽  
Vol 85 (2) ◽  
Author(s):  
Evgeny A. Semchenko ◽  
Christopher J. Day ◽  
Kate L. Seib
Keyword(s):  
Epithelial Cells ◽  
Neisseria Gonorrhoeae ◽  
Transmitted Infection ◽  
Content Type ◽  
Sexually Transmitted ◽  
Bacterial Surface ◽  
Functional Blocking ◽  
Blocking Antibodies ◽  
Candidate Antigen

ABSTRACT Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection (STI) gonorrhea, is a growing public health threat for which a vaccine is urgently needed. We characterized the functional role of the gonococcal MetQ protein, which is the methionine binding component of an ABC transporter system, and assessed its potential as a candidate antigen for inclusion in a gonococcal vaccine. MetQ has been found to be highly conserved in all strains investigated to date, it is localized on the bacterial surface, and it binds l-methionine with a high affinity. MetQ is also involved in gonococcal adherence to cervical epithelial cells. Mutants lacking MetQ have impaired survival in human monocytes, macrophages, and serum. Furthermore, antibodies raised against MetQ are bactericidal and are able to block gonococcal adherence to epithelial cells. These data suggest that MetQ elicits both bactericidal and functional blocking antibodies and is a valid candidate antigen for additional investigation and possible inclusion in a vaccine for prevention of gonorrhea.

scholarly journals Phase-Variable Expression oflptAModulates the Resistance of Neisseria gonorrhoeae to Cationic Antimicrobial Peptides

2014 ◽  
Vol 58 (7) ◽  
pp. 4230-4233 ◽  
Author(s):  
Justin L. Kandler ◽  
Sandeep J. Joseph ◽  
Jacqueline T. Balthazar ◽  
Vijaya Dhulipala ◽  
Timothy D. Read ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antimicrobial Peptides ◽  
High Frequency ◽  
Lipid A ◽  
Bacterial Resistance ◽  
Phase Variable ◽  
Cationic Antimicrobial Peptides ◽  
Content Type ◽  
Variable Expression

ABSTRACTPhosphoethanolamine (PEA) decoration of lipid A produced byNeisseria gonorrhoeaehas been linked to bacterial resistance to cationic antimicrobial peptides/proteins (CAMPs) andin vivofitness during experimental infection. We now report that thelptAgene, which encodes the PEA transferase responsible for this decoration, is in an operon and that high-frequency mutation in a polynucleotide repeat withinlptAcan influence gonococcal resistance to CAMPs.

scholarly journals MprF-Mediated Lysinylation of Phospholipids in Staphylococcus aureus Leads to Protection against Oxygen-Independent Neutrophil Killing

2003 ◽  
Vol 71 (1) ◽  
pp. 546-549 ◽  
Author(s):  
Sascha A. Kristian ◽  
Manuela Dürr ◽  
Jos A. G. Van Strijp ◽  
Birgid Neumeister ◽  
Andreas Peschel
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Peptides ◽  
Host Defense ◽  
Membrane Lipids ◽  
Human Monocytes ◽  
Wild Type ◽  
Cationic Antimicrobial Peptides ◽  
The Impact ◽  
Defense Molecules

ABSTRACT Staphylococcus aureus achieves resistance to defensins and similar cationic antimicrobial peptides (CAMPs) by modifying anionic membrane lipids via MprF with l-lysine, which leads to repulsion of these host defense molecules. S. aureus ΔmprF, which lacks the modification, was very efficiently killed by neutrophil defensins and CAMP-producing leukocytes, even when oxygen-dependent killing was disrupted, but was as susceptible as wild-type bacteria to inactivation by myeloperoxidase or human monocytes lacking defensins. These results demonstrate the impact and specificity of MprF-mediated CAMP resistance and underscore the role of defensin-like peptides in innate host defense.

scholarly journals The dlt operon confers resistance to cationic antimicrobial peptides in Clostridium difficile

Microbiology ◽  
2011 ◽  
Vol 157 (5) ◽  
pp. 1457-1465 ◽  
Author(s):  
Shonna M. McBride ◽  
Abraham L. Sonenshein
Keyword(s):  
Cell Wall ◽  
Clostridium Difficile ◽  
Antimicrobial Peptides ◽  
Positive Charge ◽  
Polymyxin B ◽  
Gram Positive ◽  
Cationic Antimicrobial Peptides ◽  
Teichoic Acids ◽  
Gram Positive Bacteria ◽  
Net Positive Charge

The dlt operon in Gram-positive bacteria encodes proteins that are necessary for the addition of d-alanine to teichoic acids of the cell wall. The addition of d-alanine to the cell wall results in a net positive charge on the bacterial cell surface and, as a consequence, can decrease the effectiveness of antimicrobials, such as cationic antimicrobial peptides (CAMPs). Although the roles of the dlt genes have been studied for some Gram-positive organisms, the arrangement of these genes in Clostridium difficile and the life cycle of the bacterium in the host are markedly different from those of other pathogens. In the current work, we determined the contribution of the putative C. difficile dlt operon to CAMP resistance. Our data indicate that the dlt operon is necessary for full resistance of C. difficile to nisin, gallidermin, polymyxin B and vancomycin. We propose that the d-alanylation of teichoic acids provides protection against antimicrobial peptides that may be essential for growth of C. difficile in the host.

scholarly journals Different effects of transcriptional regulators MarA, SoxS and Rob on susceptibility of Escherichia coli to cationic antimicrobial peptides (CAMPs): Rob-dependent CAMP induction of the marRAB operon

Microbiology ◽  
2010 ◽  
Vol 156 (2) ◽  
pp. 570-578 ◽  
Author(s):  
Douglas M. Warner ◽  
Stuart B. Levy
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Peptides ◽  
Bacterial Infections ◽  
Transcriptional Regulators ◽  
Polymyxin B ◽  
Cationic Antimicrobial Peptides ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Camp Induction ◽  
Increased Susceptibility

Cationic antimicrobial peptides (CAMPs), a component of the mammalian immune system, protect the host from bacterial infections. The roles of the Escherichia coli transcriptional regulators MarA, SoxS and Rob in susceptibility to these peptides were examined. Overexpression of marA, either in an antibiotic-resistant marR mutant or from a plasmid, decreased bacterial susceptibility to CAMPs. Overexpression of the soxS gene from a plasmid, which decreased susceptibility to antibiotics, unexpectedly caused no decrease in CAMP susceptibility; instead it produced increased susceptibility to different CAMPs. Deletion or overexpression of rob had little effect on CAMP susceptibility. The marRAB operon was upregulated when E. coli was incubated in sublethal amounts of CAMPs polymyxin B, LL-37 or human β-defensin-1; however, this upregulation required Rob. Deletion of acrAB increased bacterial susceptibility to polymyxin B, LL-37 and human β-defensin-1 peptides. Deletion of tolC yielded an even greater increase in susceptibility to these peptides and also led to increased susceptibility to human α-defensin-2. Inhibition of cellular proton-motive force increased peptide susceptibility for wild-type and acrAB deletion strains; however, it decreased susceptibility of tolC mutants. These findings demonstrate that CAMPs are both inducers of marA-mediated drug resistance through interaction with Rob and also substrates for efflux in E. coli. The three related transcriptional regulators show different effects on bacterial cell susceptibility to CAMPs.

scholarly journals The Staphylococcus aureus Two-Component Regulatory System, GraRS, Senses and Confers Resistance to Selected Cationic Antimicrobial Peptides

2011 ◽  
Vol 80 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Soo-Jin Yang ◽  
Arnold S. Bayer ◽  
Nagendra N. Mishra ◽  
Michael Meehl ◽  
Nagender Ledala ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Positive Charge ◽  
Efflux Pump ◽  
Regulatory System ◽  
Polymyxin B ◽  
Cationic Antimicrobial Peptides ◽  
Two Component ◽  
Mrsa Strains ◽  
Reduced Surface

ABSTRACTThe two-component regulatory system, GraRS, appears to be involved in staphylococcal responses to cationic antimicrobial peptides (CAPs). However, the mechanism(s) by which GraRS is induced, regulated, and modulated remain undefined. In this study, we used two well-characterized MRSA strains (Mu50 and COL) and their respective mutants ofgraRandvraG(encoding the ABC transporter-dependent efflux pump immediately downstream ofgraRS), and show that (i) the expression of two key determinants of net positive surface charge (mprFanddlt) is dependent on the cotranscription of bothgraRandvraG, (ii) reduced expression ofmprFanddltingraRmutants was phenotypically associated with reduced surface-positive charge, (iii) this net reduction in surface-positive charge ingraRandvraGmutants, in turn, correlated with enhanced killing by a range of CAPs of diverse structure and origin, including those from mammalian platelets (tPMPs) and neutrophils (hNP-1) and from bacteria (polymyxin B), and (iv) the synthesis and translocation of membrane lysyl-phosphatidylglycerol (anmprF-dependent function) was substantially lower ingraRandvraGmutants than in parental strains. Importantly, the inducibility ofmprFanddlttranscription via thegraRS-vraFGpathway was selective, with induction by sublethal exposure to the CAPs, RP-1 (platelets), and polymyxin B, but not by other cationic molecules (hNP-1, vancomycin, gentamicin, or calcium-daptomycin). AlthoughgraRregulates expression ofvraG, the expression ofgraRwas codependent on an intact downstreamvraGlocus. Collectively, these data support an important role of thegraRSandvraFGloci in the sensing of and response to specific CAPs involved in innate host defenses.

scholarly journals Identification of EnvC and Its Cognate Amidases as Novel Determinants of Intrinsic Resistance to Cationic Antimicrobial Peptides

2016 ◽  
Vol 60 (4) ◽  
pp. 2222-2231 ◽  
Author(s):  
Tamiko Oguri ◽  
Won-Sik Yeo ◽  
Taeok Bae ◽  
Hyunwoo Lee
Keyword(s):  
Antimicrobial Peptides ◽  
Common Factor ◽  
Animal Experiments ◽  
Enteric Bacteria ◽  
Polymyxin B ◽  
Intrinsic Resistance ◽  
Cationic Antimicrobial Peptides ◽  
Gram Negative ◽  
Content Type ◽  
E Coli

ABSTRACTCationic antimicrobial peptides (CAMPs) are an essential part of the innate immune system. Some Gram-negative enteric pathogens, such asSalmonella enterica, show intrinsic resistance to CAMPs. However, the molecular basis of intrinsic resistance is poorly understood, largely due to a lack of information about the genes involved. In this study, using a microarray-based genomic technique, we screened the Keio collection of 3,985Escherichia colimutants for altered susceptibility to human neutrophil peptide 1 (HNP-1) and identifiedenvCandzapBas novel genetic determinants of intrinsic CAMP resistance. In CAMP killing assays, anE. coliΔenvCEcor ΔzapBEcmutant displayed a distinct profile of increased susceptibility to both LL-37 and HNP-1. Both mutants, however, displayed wild-type resistance to polymyxin B and human β-defensin 3 (HBD3), suggesting that the intrinsic resistance mediated by EnvC or ZapB is specific to certain CAMPs. A correspondingSalmonellaΔenvCSemutant showed similarly increased CAMP susceptibility. TheenvCmutants of bothE. coliandS. entericadisplayed increased surface negativity and hydrophobicity, which partly explained the increased CAMP susceptibility. However, the ΔenvCEcmutant, but not the ΔenvCSemutant, was defective in outer membrane permeability, excluding this defect as a common factor contributing to the increased CAMP susceptibility. Animal experiments showed that theSalmonellaΔenvCSemutant had attenuated virulence. Taken together, our results indicate that the role ofenvCin intrinsic CAMP resistance is likely conserved among Gram-negative enteric bacteria, demonstrate the importance of intrinsic CAMP resistance for full virulence ofS. enterica, and provide insight into distinct mechanisms of action of CAMPs.

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