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Ledger EVK, Edwards AM. Host-induced cell wall remodeling impairs opsonophagocytosis of Staphylococcus aureus by neutrophils. mBio 2024; 15:e0164324. [PMID: 39041819 PMCID: PMC11323798 DOI: 10.1128/mbio.01643-24] [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: 05/29/2024] [Accepted: 07/02/2024] [Indexed: 07/24/2024] Open
Abstract
The bacterial pathogen Staphylococcus aureus responds to the host environment by increasing the thickness of its cell wall. However, the impact of cell wall thickening on susceptibility to host defenses is unclear. Using bacteria incubated in human serum, we show that host-induced increases in cell wall thickness led to a reduction in the exposure of bound antibody and complement and a corresponding reduction in phagocytosis and killing by neutrophils. The exposure of opsonins bound to protein antigens or lipoteichoic acid (LTA) was most significantly reduced, while opsonization by IgG against wall teichoic acid or peptidoglycan was largely unaffected. Partial digestion of accumulated cell wall using the enzyme lysostaphin restored opsonin exposure and promoted phagocytosis and killing. Concordantly, the antibiotic fosfomycin inhibited cell wall remodeling and maintained the full susceptibility of S. aureus to opsonophagocytic killing by neutrophils. These findings reveal that host-induced changes to the S. aureus cell wall reduce the ability of the immune system to detect and kill this pathogen through reduced exposure of protein- and LTA-bound opsonins. IMPORTANCE Understanding how bacteria adapt to the host environment is critical in determining fundamental mechanisms of immune evasion, pathogenesis, and the identification of targets for new therapeutic approaches. Previous work demonstrated that Staphylococcus aureus remodels its cell envelope in response to host factors and we hypothesized that this may affect recognition by antibodies and thus killing by immune cells. As expected, incubation of S. aureus in human serum resulted in rapid binding of antibodies. However, as bacteria adapted to the serum, the increase in cell wall thickness resulted in a significant reduction in exposure of bound antibodies. This reduced antibody exposure, in turn, led to reduced killing by human neutrophils. Importantly, while antibodies bound to some cell surface structures became obscured, this was not the case for those bound to wall teichoic acid, which may have important implications for vaccine design.
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Affiliation(s)
- Elizabeth V. K. Ledger
- Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
| | - Andrew M. Edwards
- Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
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Jobson ME, Tomlinson BR, Mustor EM, Felton EA, Weiss A, Caswell CC, Shaw LN. SSR42 is a Novel Regulator of Cytolytic Activity in Staphylococcus aureus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.11.603084. [PMID: 39026779 PMCID: PMC11257634 DOI: 10.1101/2024.07.11.603084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
SSR42 is the longest noncoding RNA in the S. aureus cell and the second-most abundant transcript in the stationary phase transcriptome, second only to RNAIII. It is highly conserved across strains and exhibits pronounced stability in stationary phase, however the mechanism behind its regulatory role has yet to be fully elucidated. Herein, we used transcriptomic and proteomic approaches to probe the role of SSR42, revealing that it is a powerful, novel activator of the primary leukocidin LukAB. SSR42 is required for cytotoxicity towards, and escape from within, human neutrophils, and also mediates survival within human blood. We show that SSR42 wields this role via derepression by the peroxide repressor PerR in response to the presence of human neutrophils and governs lukAB induction in this niche. Importantly, this regulation is driven by direct RNA-RNA interaction, as we show binding of the 5' UTR of the lukAB transcript with the 3' end of SSR42, which ultimately modulates transcript stability as well as translational activity. Finally, we demonstrate that this behavior is absolutely required for full virulence of S. aureus in murine models of both pneumonia and sepsis. Collectively, we present SSR42 as a pleiotropic regulatory RNA that acts as a nexus between environmental sensing and the regulation of pathogenesis, responding to environmental stimuli and host immune factors to bolster cytotoxic behavior and facilitate infection in S. aureus . Importance S. aureus is a master pathogen due to its formidable collection of virulence factors. These are tightly controlled by a diverse group of regulators that titrate their abundance to adapt to unique infectious niches. The role of regulatory RNAs in stress adaptation and pathogenesis is becoming increasingly more relevant in S. aureus . In this study, we provide the most comprehensive global analysis to date of just such a factor, SSR42. Specifically, we uncover that SSR42 is required for mediating cytotoxicity - one of the pillars of infection - in response to phagocytosis by human neutrophils. We find that SSR42 is induced by components of the host immune system and facilitates downstream activation of cytotoxic factors via RNA-RNA interactions. This illustrates that SSR42 forms a pivotal link between sensing the external environment and mediating resistance to oxidative stress while promoting virulence, solidifying it as a major global regulator in S. aureus .
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Petersen ME, Hansen LK, Mitkin AA, Kelly NM, Wood TK, Jørgensen NP, Østergaard LJ, Meyer RL. A high-throughput assay identifies molecules with antimicrobial activity against persister cells. J Med Microbiol 2024; 73:001856. [PMID: 38995832 PMCID: PMC11316564 DOI: 10.1099/jmm.0.001856] [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: 03/26/2024] [Accepted: 06/13/2024] [Indexed: 07/14/2024] Open
Abstract
Introduction. Persister cells are transiently non-growing antibiotic-tolerant bacteria that cause infection relapse, and there is no effective antibiotic therapy to tackle these infections.Gap statement. High-throughput assays in drug discovery are biased towards detecting drugs that inhibit bacterial growth rather than killing non-growing bacteria. A new and simple assay to discover such drugs is needed.Aim. This study aims to develop a simple and high-throughput assay to identify compounds with antimicrobial activity against persister cells and use it to identify molecular motifs with such activity.Methodology. We quantified Staphylococcus aureus persister cells by enumeration of colony forming units after 24 h ciprofloxacin treatment. We first quantified how the cell concentration, antibiotic concentration, growth phase and presence/absence of nutrients during antibiotic exposure affected the fraction of persister cells in a population. After optimizing these parameters, we screened the antimicrobial activity of compound fragments to identify molecular structures that have activity against persister cells.Results. Exponential- and stationary-phase cultures transferred to nutrient-rich media displayed a bi-phasic time-kill curve and contained 0.001-0.07% persister cells. A short rifampicin treatment resulted in 100% persister cells for 7 h, after which cells resumed activity and became susceptible. Stationary-phase cultures displayed a low but constant death rate but ultimately resulted in similarly low survival rates as the exponential-phase cultures after 24 h ciprofloxacin treatment. The persister phenotype was only maintained in most of the population for 24 h if cells were transferred to a carbon-free minimal medium before exposure to ciprofloxacin. Keeping cells starved enabled the generation of high concentrations of S. aureus cells that tolerate 50× MIC ciprofloxacin, and we used this protocol for rapid screening for biocidal antibiotics. We identified seven compounds from four structural clusters with activity against antibiotic-tolerant S. aureus. Two compounds were moderately cytotoxic, and the rest were highly cytotoxic.Conclusion. Transferring a stationary-phase culture to a carbon-free minimal medium for antimicrobial testing is a simple strategy for high-throughput screening for new antibiotics that kill persister cells. We identified molecule fragments with such activity, but further screening is needed to identify motifs with lower general cytotoxicity.
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Affiliation(s)
| | - Liva Kjær Hansen
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | | | | | - Thomas Keith Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, USA
| | - Nis Pedersen Jørgensen
- Department of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark
- Department of Infectious Diseases, Aarhus University Hospital, 8200 Aarhus N, Denmark
| | - Lars Jørgen Østergaard
- Department of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark
- Department of Infectious Diseases, Aarhus University Hospital, 8200 Aarhus N, Denmark
| | - Rikke Louise Meyer
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, 8000 Aarhus C, Denmark
- Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
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Liu Y, McQuillen EA, Rana PSJB, Gloag ES, Parsek MR, Wozniak DJ. A bacterial pigment provides cross-species protection from H 2O 2- and neutrophil-mediated killing. Proc Natl Acad Sci U S A 2024; 121:e2312334121. [PMID: 38170744 PMCID: PMC10786307 DOI: 10.1073/pnas.2312334121] [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: 07/19/2023] [Accepted: 11/29/2023] [Indexed: 01/05/2024] Open
Abstract
Bacterial infections are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus cause chronic co-infections, which are more problematic than mono-species infections. Understanding the mechanisms of their interactions is crucial for treating co-infections. Staphyloxanthin (STX), a yellow pigment synthesized by the S. aureus crt operon, promotes S. aureus resistance to oxidative stress and neutrophil-mediated killing. We found that STX production by S. aureus, either as surface-grown macrocolonies or planktonic cultures, was elevated when exposed to the P. aeruginosa exoproduct, 2-heptyl-4-hydroxyquinoline N-oxide (HQNO). This was observed with both mucoid and non-mucoid P. aeruginosa strains. The induction phenotype was found in a majority of P. aeruginosa and S. aureus clinical isolates examined. When subjected to hydrogen peroxide or human neutrophils, P. aeruginosa survival was significantly higher when mixed with wild-type (WT) S. aureus, compared to P. aeruginosa alone or with an S. aureus crt mutant deficient in STX production. In a murine wound model, co-infection with WT S. aureus, but not the STX-deficient mutant, enhanced P. aeruginosa burden and disease compared to mono-infection. In conclusion, we identified a role for P. aeruginosa HQNO mediating polymicrobial interactions with S. aureus by inducing STX production, which consequently promotes resistance to the innate immune effectors H2O2 and neutrophils. These results further our understanding of how different bacterial species cooperatively cause co-infections.
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Affiliation(s)
- Yiwei Liu
- Department of Microbiology, Ohio State University, Columbus, OH43210
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, OH43210
| | - Eleanor A. McQuillen
- Department of Health and Rehabilitation Sciences, Ohio State University College of Medicine, Columbus, OH43210
| | - Pranav S. J. B. Rana
- Department of Microbiology, Ohio State University, Columbus, OH43210
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, OH43210
| | - Erin S. Gloag
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, OH43210
- Department of Biomedical Sciences and Pathobiology, Virginia Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA24060
| | - Matthew R. Parsek
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA98195
| | - Daniel J. Wozniak
- Department of Microbiology, Ohio State University, Columbus, OH43210
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, OH43210
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5
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Tzalis S, Ioannou P, Billiari E, Kofteridis DP, Karakonstantis S. Daptomycin as an option for lock therapy: a systematic literature review. Future Microbiol 2023; 18:917-928. [PMID: 37622290 DOI: 10.2217/fmb-2023-0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023] Open
Abstract
Aim: To review preclinical and clinical data relevant to daptomycin lock therapy in catheter-related bloodstream infection (CRBSI). Methods: Systematic review in PubMed, Scopus and clinical trial registries. Results: Preclinical data demonstrate daptomycin lock solution stability and compatibility with heparin, good biofilm penetration, bactericidal activity against biofilm-embedded bacteria, and high efficacy in vitro and in animal catheter infection models. Clinical data remain limited (two case reports and five case series totaling n = 65 CRBSI episodes), albeit promising (successful catheter salvage in about 80% of cases). Conclusion: Despite theoretical advantages of daptomycin, clinical data remain scarce. Comparative studies versus alternative lock solutions are needed, as well as studies to define optimal daptomycin lock regimen (including optimal concentration, dwell time and lock duration).
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Affiliation(s)
- Sotirios Tzalis
- Department of Internal Medicine, University Hospital of Heraklion, Heraklion, Crete, 71500,Greece
| | - Petros Ioannou
- Department of Internal Medicine, University Hospital of Heraklion, Heraklion, Crete, 71500,Greece
- School of Medicine, University of Crete, Heraklion, Crete, 71500, Greece
- Infectious Diseases, University Hospital of Heraklion, Heraklion, Crete, 71500, Greece
| | - Eleni Billiari
- School of Medicine, University of Crete, Heraklion, Crete, 71500, Greece
| | - Diamantis P Kofteridis
- Department of Internal Medicine, University Hospital of Heraklion, Heraklion, Crete, 71500,Greece
- School of Medicine, University of Crete, Heraklion, Crete, 71500, Greece
- Infectious Diseases, University Hospital of Heraklion, Heraklion, Crete, 71500, Greece
| | - Stamatis Karakonstantis
- Department of Internal Medicine, University Hospital of Heraklion, Heraklion, Crete, 71500,Greece
- Infectious Diseases, University Hospital of Heraklion, Heraklion, Crete, 71500, Greece
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Bollen C, Louwagie E, Verstraeten N, Michiels J, Ruelens P. Environmental, mechanistic and evolutionary landscape of antibiotic persistence. EMBO Rep 2023; 24:e57309. [PMID: 37395716 PMCID: PMC10398667 DOI: 10.15252/embr.202357309] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/07/2023] [Accepted: 06/16/2023] [Indexed: 07/04/2023] Open
Abstract
Recalcitrant infections pose a serious challenge by prolonging antibiotic therapies and contributing to the spread of antibiotic resistance, thereby threatening the successful treatment of bacterial infections. One potential contributing factor in persistent infections is antibiotic persistence, which involves the survival of transiently tolerant subpopulations of bacteria. This review summarizes the current understanding of antibiotic persistence, including its clinical significance and the environmental and evolutionary factors at play. Additionally, we discuss the emerging concept of persister regrowth and potential strategies to combat persister cells. Recent advances highlight the multifaceted nature of persistence, which is controlled by deterministic and stochastic elements and shaped by genetic and environmental factors. To translate in vitro findings to in vivo settings, it is crucial to include the heterogeneity and complexity of bacterial populations in natural environments. As researchers continue to gain a more holistic understanding of this phenomenon and develop effective treatments for persistent bacterial infections, the study of antibiotic persistence is likely to become increasingly complex.
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Affiliation(s)
- Celien Bollen
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
| | - Elen Louwagie
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
| | - Natalie Verstraeten
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
| | - Jan Michiels
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
| | - Philip Ruelens
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
- Laboratory of Socioecology and Social EvolutionKU LeuvenLeuvenBelgium
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7
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Liu Y, McQuillen EA, Rana PSJB, Gloag ES, Wozniak DJ. Cross-Species Protection to Innate Immunity Mediated by A Bacterial Pigment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.15.524085. [PMID: 36711503 PMCID: PMC9882196 DOI: 10.1101/2023.01.15.524085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Bacterial infections are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus cause chronic co-infections, which are more problematic than mono-species infections. We found that the production of S. aureus membrane-bound pigment staphyloxanthin (STX), was induced by the P. aeruginosa exoproduct, 2-heptyl-4-hydroxyquinoline N-oxide (HQNO). The induction phenotype was conserved in P. aeruginosa and S. aureus clinical isolates examined. When subjected to hydrogen peroxide or human neutrophils, P. aeruginosa survival was significantly higher when mixed with wild-type (WT) S. aureus , compared to a mutant deficient in STX production or P. aeruginosa alone. In a murine wound model, co-infection with WT S. aureus , but not the STX-deficient mutant, enhanced P. aeruginosa burden and disease compared to mono-infection. In conclusion, we discovered a novel role for P. aeruginosa HQNO mediating polymicrobial interactions with S. aureus by inducing STX production, which consequently promotes resistance of both pathogens to innate immune effectors. These results further our understanding of how different bacterial species cooperatively cause co-infections.
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8
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Huber C, Wolf SA, Ziebuhr W, Holmes MA, Assmann J, Lübke-Becker A, Thürmer A, Semmler T, Brombach J, Bethe A, Bischoff M, Wieler LH, Epping L, Walther B. How to survive pig farming: Mechanism of SCC mec element deletion and metabolic stress adaptation in livestock-associated MRSA. Front Microbiol 2022; 13:969961. [PMID: 36504815 PMCID: PMC9728531 DOI: 10.3389/fmicb.2022.969961] [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] [Received: 06/15/2022] [Accepted: 10/04/2022] [Indexed: 11/24/2022] Open
Abstract
Previous research on methicillin susceptible Staphylococcus aureus (MSSA) belonging to livestock-associated (LA-) sequence type (ST) 398, isolated from pigs and their local surroundings, indicated that differences between these MSSA and their methicillin resistant predecessors (MRSA) are often limited to the absence of the staphylococcal cassette chromosome mec (SCCmec) and few single nucleotide polymorphisms. So far, our understanding on how LA-MRSA endure the environmental conditions associated with pig-farming as well as the putative impact of this particular environment on the mobilisation of SCCmec elements is limited. Thus, we performed in-depth genomic and transcriptomic analyses using the LA-MRSA ST398 strain IMT38951 and its methicillin susceptible descendant. We identified a mosaic-structured SCCmec region including a putative replicative SCCmecVc which is absent from the MSSA chromosome through homologous recombination. Based on our data, such events occur between short repetitive sequences identified within and adjacent to two distinct alleles of the large cassette recombinase genes C (ccrC). We further evaluated the global transcriptomic response of MRSA ST398 to particular pig-farm associated conditions, i.e., contact with host proteins (porcine serum) and a high ammonia concentration. Differential expression of global regulators involved in stress response control were identified, i.e., ammonia-induced alternative sigma factor B-depending activation of genes for the alkaline shock protein 23, the heat shock response and the accessory gene regulator (agr)-controlled transcription of virulence factors. Exposure to serum transiently induced the transcription of distinct virulence factor encoding genes. Transcription of genes reported for mediating the loss of methicillin resistance, especially ccrC, was not significantly different compared to the unchallenged controls. We concluded that, from an evolutionary perspective, bacteria may save energy by incidentally dismissing a fully replicative SCCmec element in contrast to the induction of ccr genes on a population scale. Since the genomic SCCmec integration site is a hot-spot of recombination, occasional losses of elements of 16 kb size may restore capacities for the uptake of foreign genetic material. Subsequent spread of resistance, on the other hand, might depend on the autonomous replication machinery of the deleted SCCmec elements that probably enhance chances for reintegration of SCCmec into susceptible genomes by mere multiplication.
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Affiliation(s)
- Charlotte Huber
- Advanced Light and Electron Microscopy (ZBS4), Robert Koch Institute, Berlin, Germany
| | - Silver A. Wolf
- Genome Sequencing and Genomic Epidemiology (MF2), Robert Koch Institute, Berlin, Germany
| | - Wilma Ziebuhr
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Mark A. Holmes
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Julia Assmann
- Advanced Light and Electron Microscopy (ZBS4), Robert Koch Institute, Berlin, Germany
| | - Antina Lübke-Becker
- Institute of Microbiology and Epizootics, Freie Universität Berlin, Berlin, Germany
| | - Andrea Thürmer
- Genome Sequencing and Genomic Epidemiology (MF2), Robert Koch Institute, Berlin, Germany
| | - Torsten Semmler
- Genome Sequencing and Genomic Epidemiology (MF2), Robert Koch Institute, Berlin, Germany
| | - Julian Brombach
- Institute of Microbiology and Epizootics, Freie Universität Berlin, Berlin, Germany
| | - Astrid Bethe
- Institute of Microbiology and Epizootics, Freie Universität Berlin, Berlin, Germany
| | - Markus Bischoff
- Institute of Medical Microbiology and Hygiene, Saarland University, Homburg, Germany
| | - Lothar H. Wieler
- Methodology and Research Infrastructure, Robert Koch Institute, Berlin, Germany
| | - Lennard Epping
- Genome Sequencing and Genomic Epidemiology (MF2), Robert Koch Institute, Berlin, Germany
| | - Birgit Walther
- Advanced Light and Electron Microscopy (ZBS4), Robert Koch Institute, Berlin, Germany,*Correspondence: Birgit Walther,
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Menard G, Silard C, Suriray M, Rouillon A, Augagneur Y. Thirty Years of sRNA-Mediated Regulation in Staphylococcus aureus: From Initial Discoveries to In Vivo Biological Implications. Int J Mol Sci 2022; 23:ijms23137346. [PMID: 35806357 PMCID: PMC9266662 DOI: 10.3390/ijms23137346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/20/2022] [Accepted: 06/28/2022] [Indexed: 01/27/2023] Open
Abstract
Staphylococcus aureus is a widespread livestock and human pathogen that colonizes diverse microenvironments within its host. Its adaptation to the environmental conditions encountered within humans relies on coordinated gene expression. This requires a sophisticated regulatory network, among which regulatory RNAs (usually called sRNAs) have emerged as key players over the last 30 years. In S. aureus, sRNAs regulate target genes at the post-transcriptional level through base–pair interactions. The functional characterization of a subset revealed that they participate in all biological processes, including virulence, metabolic adaptation, and antibiotic resistance. In this review, we report 30 years of S. aureus sRNA studies, from their discovery to the in-depth characterizations of some of them. We also discuss their actual in vivo contribution, which is still lagging behind, and their place within the complex regulatory network. These shall be key aspects to consider in order to clearly uncover their in vivo biological functions.
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Affiliation(s)
- Guillaume Menard
- CHU Rennes, INSERM, BRM (Bacterial Regulatory RNAs and Medicine), SB2H (Service de Bactériologie Hygiène-Hospitalière), University Rennes, UMR_S 1230, F-35000 Rennes, France; (G.M.); (M.S.)
| | - Chloé Silard
- INSERM, BRM (Bacterial Regulatory RNAs and Medicine), University Rennes, UMR_S 1230, F-35000 Rennes, France; (C.S.); (A.R.)
| | - Marie Suriray
- CHU Rennes, INSERM, BRM (Bacterial Regulatory RNAs and Medicine), SB2H (Service de Bactériologie Hygiène-Hospitalière), University Rennes, UMR_S 1230, F-35000 Rennes, France; (G.M.); (M.S.)
| | - Astrid Rouillon
- INSERM, BRM (Bacterial Regulatory RNAs and Medicine), University Rennes, UMR_S 1230, F-35000 Rennes, France; (C.S.); (A.R.)
| | - Yoann Augagneur
- INSERM, BRM (Bacterial Regulatory RNAs and Medicine), University Rennes, UMR_S 1230, F-35000 Rennes, France; (C.S.); (A.R.)
- Correspondence: ; Tel.: +33-223234631
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10
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Ledger EVK, Mesnage S, Edwards AM. Human serum triggers antibiotic tolerance in Staphylococcus aureus. Nat Commun 2022; 13:2041. [PMID: 35440121 PMCID: PMC9018823 DOI: 10.1038/s41467-022-29717-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/30/2022] [Indexed: 12/13/2022] Open
Abstract
Staphylococcus aureus frequently causes infections that are challenging to treat, leading to high rates of persistent and relapsing infection. Here, to understand how the host environment influences treatment outcomes, we study the impact of human serum on staphylococcal antibiotic susceptibility. We show that serum triggers a high degree of tolerance to the lipopeptide antibiotic daptomycin and several other classes of antibiotic. Serum-induced daptomycin tolerance is due to two independent mechanisms. Firstly, the host defence peptide LL-37 induces tolerance by triggering the staphylococcal GraRS two-component system, leading to increased peptidoglycan accumulation. Secondly, GraRS-independent increases in membrane cardiolipin abundance are required for full tolerance. When both mechanisms are blocked, S. aureus incubated in serum is as susceptible to daptomycin as when grown in laboratory media. Our work demonstrates that host factors can significantly modulate antibiotic susceptibility via diverse mechanisms, and combination therapy may provide a way to mitigate this.
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Affiliation(s)
- Elizabeth V K Ledger
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Rd, London, SW7 2AZ, UK
| | - Stéphane Mesnage
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Andrew M Edwards
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Rd, London, SW7 2AZ, UK.
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11
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Trinh QD. Recent Research in Cell Stress and Microbial Infection. Microorganisms 2022; 10:622. [PMID: 35336195 PMCID: PMC8951272 DOI: 10.3390/microorganisms10030622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 03/12/2022] [Indexed: 02/06/2023] Open
Abstract
Microbial infection, including bacterial, viral, fungal, and parasitic, is a common human disease leading to various cell stresses [...].
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Affiliation(s)
- Quang Duy Trinh
- Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo 173-8610, Japan
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12
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Joshi C, Kothari V. Bacterial Stress-response Machinery as a Target for Next-generation Antimicrobials. Infect Disord Drug Targets 2022; 22:e210322202493. [PMID: 35319398 DOI: 10.2174/1871526522666220321153332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 10/30/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Affiliation(s)
- Chinmayi Joshi
- Smt. S.S.Patel Nootan Science and Commerce College, Sankalchand Patel University, Visnagar 384315, India
| | - Vijay Kothari
- Institute of Science, Nirma University, Ahmedabad 382481, India
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13
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The intracellular phase of extracellular respiratory tract bacterial pathogens and its role on pathogen-host interactions during infection. Curr Opin Infect Dis 2021; 34:197-205. [PMID: 33899754 DOI: 10.1097/qco.0000000000000727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW An initial intracellular phase of usually extracellular bacterial pathogens displays an important strategy to hide from the host's immune system and antibiotics therapy. It helps the bacteria, including bacterial pathogens of airway diseases, to persist and eventually switch to a typical extracellular infection. Several infectious diseases of the lung are life-threatening and their control is impeded by intracellular persistence of pathogens. Thus, molecular adaptations of the pathogens to this niche but also the host's response and potential targets to interfere are of relevance. Here we discuss examples of historically considered extracellular pathogens of the respiratory airway where the intracellular survival and proliferation is well documented, including infections by Staphylococcus aureus, Bordetella pertussis, Haemophilus influenzae, Pseudomonas aeruginosa, and others. RECENT FINDINGS Current studies focus on bacterial factors contributing to adhesion, iron acquisition, and intracellular survival as well as ways to target them for combatting the bacterial infections. SUMMARY The investigation of common and specific mechanisms of pathogenesis and persistence of these bacteria in the host may contribute to future investigations and identifications of relevant factors and/or bacterial mechanisms to be blocked to treat or improve prevention strategies.
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Reactive Oxygen Species-Dependent Innate Immune Mechanisms Control Methicillin-Resistant Staphylococcus aureus Virulence in the Drosophila Larval Model. mBio 2021; 12:e0027621. [PMID: 34126772 PMCID: PMC8262968 DOI: 10.1128/mbio.00276-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Antibiotic-resistant Staphylococcus aureus strains constitute a major public health concern worldwide and are responsible for both health care- and community-associated infections. Here, we establish a robust and easy-to-implement model of oral S. aureus infection using Drosophila melanogaster larvae that allowed us to follow the fate of S. aureus at the whole-organism level as well as the host immune responses. Our study demonstrates that S. aureus infection triggers H2O2 production by the host via the Duox enzyme, thereby promoting antimicrobial peptide production through activation of the Toll pathway. Staphylococcal catalase mediates H2O2 neutralization, which not only promotes S. aureus survival but also minimizes the host antimicrobial response, hence reducing bacterial clearance in vivo. We show that while catalase expression is regulated in vitro by the accessory gene regulatory system (Agr) and the general stress response regulator sigma B (SigB), it no longer depends on these two master regulators in vivo. Finally, we confirm the versatility of this model by demonstrating the colonization and host stimulation capabilities of S. aureus strains belonging to different sequence types (CC8 and CC5) as well as of two other bacterial pathogens, Salmonella enterica serovar Typhimurium and Shigella flexneri. Thus, the Drosophila larva can be a general model to follow in vivo the innate host immune responses triggered during infection by human pathogens.
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Wang X, Koffi PF, English OF, Lee JC. Staphylococcus aureus Extracellular Vesicles: A Story of Toxicity and the Stress of 2020. Toxins (Basel) 2021; 13:toxins13020075. [PMID: 33498438 PMCID: PMC7909408 DOI: 10.3390/toxins13020075] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 12/22/2022] Open
Abstract
Staphylococcus aureus generates and releases extracellular vesicles (EVs) that package cytosolic, cell-wall associated, and membrane proteins, as well as glycopolymers and exoproteins, including alpha hemolysin, leukocidins, phenol-soluble modulins, superantigens, and enzymes. S. aureus EVs, but not EVs from pore-forming toxin-deficient strains, were cytolytic for a variety of mammalian cell types, but EV internalization was not essential for cytotoxicity. Because S. aureus is subject to various environmental stresses during its encounters with the host during infection, we assessed how these exposures affected EV production in vitro. Staphylococci grown at 37 °C or 40 °C did not differ in EV production, but cultures incubated at 30 °C yielded more EVs when grown to the same optical density. S. aureus cultivated in the presence of oxidative stress, in iron-limited media, or with subinhibitory concentrations of ethanol, showed greater EV production as determined by protein yield and quantitative immunoblots. In contrast, hyperosmotic stress or subinhibitory concentrations of erythromycin reduced S. aureus EV yield. EVs represent a novel S. aureus secretory system that is affected by a variety of stress responses and allows the delivery of biologically active pore-forming toxins and other virulence determinants to host cells.
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Thomas GH. Microbial Musings - November 2020. MICROBIOLOGY (READING, ENGLAND) 2020; 166:1004-1006. [PMID: 33252324 PMCID: PMC7723258 DOI: 10.1099/mic.0.001005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Gavin H Thomas
- Department of Biology, University of York, PO Box 373, York, UK
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