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Bevivino G, Maurizi L, Ammendolia MG, Longhi C, Arcà B, Lombardo F. Peptides with Antimicrobial Activity in the Saliva of the Malaria Vector Anopheles coluzzii. Int J Mol Sci 2024; 25:5529. [PMID: 38791567 PMCID: PMC11121840 DOI: 10.3390/ijms25105529] [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: 04/27/2024] [Revised: 05/13/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
Mosquito saliva plays a crucial physiological role in both sugar and blood feeding by helping sugar digestion and exerting antihemostatic functions. During meal acquisition, mosquitoes are exposed to the internalization of external microbes. Since mosquitoes reingest significant amounts of saliva during feeding, we hypothesized that salivary antimicrobial components may participate in the protection of mouthparts, the crop, and the gut by inhibiting bacterial growth. To identify novel potential antimicrobials from mosquito saliva, we selected 11 candidates from Anopheles coluzzii salivary transcriptomic datasets and obtained them either using a cell-free transcription/translation expression system or, when feasible, via chemical synthesis. Hyp6.2 and hyp13, which were predicted to be produced as propeptides and cleaved in shorter mature forms, showed the most interesting results in bacterial growth inhibition assays. Hyp6.2 (putative mature form, 35 amino acid residues) significantly inhibited the growth of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli and Serratia marcescens) bacteria. Hyp13 (short form, 19 amino acid residues) dose-dependently inhibited E. coli and S. marcescens growth, inducing membrane disruption in both Gram-positive and Gram-negative bacteria as indicated with scanning electron microscopy. In conclusion, we identified two A. coluzzii salivary peptides inhibiting Gram-positive and Gram-negative bacteria growth and possibly contributing to the protection of mosquito mouthparts and digestive tracts from microbial infection during and/or after feeding.
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Affiliation(s)
- Giulia Bevivino
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (G.B.); (L.M.); (C.L.); (B.A.)
| | - Linda Maurizi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (G.B.); (L.M.); (C.L.); (B.A.)
| | - Maria Grazia Ammendolia
- National Center for Innovative Technologies in Public Health, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy;
| | - Catia Longhi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (G.B.); (L.M.); (C.L.); (B.A.)
| | - Bruno Arcà
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (G.B.); (L.M.); (C.L.); (B.A.)
| | - Fabrizio Lombardo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (G.B.); (L.M.); (C.L.); (B.A.)
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2
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Costa FG, Mills KB, Crosby HA, Horswill AR. The Staphylococcus aureus regulatory program in a human skin-like environment. mBio 2024; 15:e0045324. [PMID: 38546267 PMCID: PMC11077960 DOI: 10.1128/mbio.00453-24] [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: 02/16/2024] [Accepted: 03/04/2024] [Indexed: 04/09/2024] Open
Abstract
Staphylococcus aureus is a Gram-positive pathogen responsible for the majority of skin and soft tissue infections (SSTIs). S. aureus colonizes the anterior nares of approximately 20%-30% of the population and transiently colonizes the skin, thereby increasing the risk of developing SSTIs and more serious infections. Current laboratory models that mimic the skin surface environment are expensive, require substantial infrastructure, and limit the scope of bacterial physiology studies under human skin conditions. To overcome these limitations, we developed a cost-effective, open-source, chemically defined media recipe termed skin-like medium (SLM) that incorporates key aspects of the human skin surface environment and supports growth of several staphylococcal species. We utilized SLM to investigate the transcriptional response of methicillin-resistant Staphylococcus aureus (MRSA) following growth in SLM compared to a commonly used laboratory media. Through RNA-seq analysis, we observed the upregulation of several virulence factors, including genes encoding functions involved in adhesion, proteolysis, and cytotoxicity. To further explore these findings, we conducted quantitative reverse transcription-PCR (qRT-PCR) experiments to determine the influence of media composition, pH, and temperature on the transcriptional response of key factors involved in adhesion and virulence. We also demonstrated that MRSA primed in SLM adhered better to human corneocytes and demonstrated adhesin-specific phenotypes that previously required genetic manipulation. This improved adherence to corneocytes was dependent on both acidic pH and growth in SLM. These results support the potential utility of SLM as an in vitro model for assessing staphylococcal physiology and metabolism on human skin. IMPORTANCE Staphylococcus aureus is the major cause of skin diseases, and its increased prevalence in skin colonization and infections present a need to understand its physiology in this environment. The work presented here outlines S. aureus upregulation of colonization and virulence factors using a newly developed medium that strives to replicate the human skin surface environment and demonstrates roles for adhesins clumping factor A (ClfA), serine-rich repeat glycoprotein adhesin (SraP), and the fibronectin binding proteins (Fnbps) in human corneocyte adherence.
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Affiliation(s)
- Flavia G. Costa
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Krista B. Mills
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Heidi A. Crosby
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Veterans Affairs, Eastern Colorado Healthcare System, Aurora, Colorado, USA
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3
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Costa FG, Mills KB, Crosby HA, Horswill AR. The Staphylococcus aureus regulatory program in a human skin-like environment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563767. [PMID: 37961268 PMCID: PMC10634794 DOI: 10.1101/2023.10.24.563767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Staphylococcus aureus is a Gram-positive pathogen responsible for the majority of skin and soft tissue infections (SSTIs). S. aureus colonizes the anterior nares of approximately 20-30% of the population and transiently colonizes the skin, thereby increasing the risk of developing SSTIs and more serious infections. Current laboratory models that mimic the skin surface environment are expensive, require substantial infrastructure, and limit the scope of bacterial physiology studies under human skin conditions. To overcome these limitations, we developed a cost-effective, open-source, chemically defined media recipe termed skin-like media (SLM) that incorporates key aspects of the human skin surface environment and supports growth of several Staphylococcal species. We utilized SLM to investigate the transcriptional response of methicillin-resistant S. aureus (MRSA) following growth in SLM compared to a commonly used laboratory media. Through RNA-seq analysis, we observed the upregulation of several virulence factors, including genes encoding functions involved in adhesion, proteolysis, and cytotoxicity. To further explore these findings, we conducted qRT-PCR experiments to determine the influence of media composition, pH, and temperature on the transcriptional response of key factors involved in adhesion and virulence. We also demonstrated that MRSA primed in SLM adhered better to human corneocytes and demonstrated adhesin-specific phenotypes that previously required genetic manipulation. These results support the potential utility of SLM as an in vitro model for assessing Staphylococcal physiology and metabolism on human skin. Importance Staphylococcus aureus is the major cause of skin diseases, and its increased prevalence in skin colonization and infections present a need to understand its physiology in this environment. The work presented here outlines S. aureus upregulation of colonization and virulence factors using a newly developed media that strives to replicate the human skin surface environment, and demonstrates roles for adhesins ClfA, SraP, and Fnbps in human corneocyte adherence.
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4
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Linz MS, Mattappallil A, Finkel D, Parker D. Clinical Impact of Staphylococcus aureus Skin and Soft Tissue Infections. Antibiotics (Basel) 2023; 12:antibiotics12030557. [PMID: 36978425 PMCID: PMC10044708 DOI: 10.3390/antibiotics12030557] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/03/2023] [Accepted: 03/09/2023] [Indexed: 03/14/2023] Open
Abstract
The pathogenic bacterium Staphylococcus aureus is the most common pathogen isolated in skin-and-soft-tissue infections (SSTIs) in the United States. Most S. aureus SSTIs are caused by the epidemic clone USA300 in the USA. These infections can be serious; in 2019, SSTIs with S. aureus were associated with an all-cause, age-standardized mortality rate of 0.5 globally. Clinical presentations of S. aureus SSTIs vary from superficial infections with local symptoms to monomicrobial necrotizing fasciitis, which can cause systemic manifestations and may lead to serious complications or death. In order to cause skin infections, S. aureus employs a host of virulence factors including cytolytic proteins, superantigenic factors, cell wall-anchored proteins, and molecules used for immune evasion. The immune response to S. aureus SSTIs involves initial responders such as keratinocytes and neutrophils, which are supported by dendritic cells and T-lymphocytes later during infection. Treatment for S. aureus SSTIs is usually oral therapy, with parenteral therapy reserved for severe presentations; it ranges from cephalosporins and penicillin agents such as oxacillin, which is generally used for methicillin-sensitive S. aureus (MSSA), to vancomycin for methicillin-resistant S. aureus (MRSA). Treatment challenges include adverse effects, risk for Clostridioides difficile infection, and potential for antibiotic resistance.
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Affiliation(s)
- Matthew S. Linz
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Arun Mattappallil
- Department of Pharmaceutical Services, University Hospital, Newark, NJ 07103, USA
| | - Diana Finkel
- Division of Infectious Diseases, Department of Medicine, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Dane Parker
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
- Correspondence: ; Fax: +1-973-972-3047
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5
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Shelley JR, McHugh BJ, Wills J, Dorin JR, Weller R, Clarke DJ, Davidson DJ. A mechanistic evaluation of human beta defensin 2 mediated protection of human skin barrier in vitro. Sci Rep 2023; 13:2271. [PMID: 36755116 PMCID: PMC9908873 DOI: 10.1038/s41598-023-29558-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
The human skin barrier, a biological imperative, is impaired in inflammatory skin diseases such as atopic dermatitis (AD). Staphylococcus aureus is associated with AD lesions and contributes to pathological inflammation and further barrier impairment. S. aureus secretes extracellular proteases, such as V8 (or 'SspA'), which cleave extracellular proteins to reduce skin barrier. Previous studies demonstrated that the host defence peptide human beta-defensin 2 (HBD2) prevented V8-mediated damage. Here, the mechanism of HBD2-mediated barrier protection in vitro is examined. Application of exogenous HBD2 provided protection against V8, irrespective of timeline of application or native peptide folding, raising the prospect of simple peptide analogues as therapeutics. HBD2 treatment, in context of V8-mediated damage, modulated the proteomic/secretomic profiles of HaCaT cells, altering levels of specific extracellular matrix proteins, potentially recovering V8 damage. However, HBD2 alone did not substantially modulate cellular proteomic/secretomics profiles in the absence of damage, suggesting possible therapeutic targeting of lesion damage sites only. HBD2 did not show any direct protease inhibition or induce expression of known antiproteases, did not alter keratinocyte migration or proliferation, or form protective nanonet structures. These data validate the barrier-protective properties of HBD2 in vitro and establish key protein datasets for further targeted mechanistic analyses.
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Affiliation(s)
- Jennifer R Shelley
- University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, Scotland, UK.
- The Commonwealth Building, The Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
| | - Brian J McHugh
- University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, Scotland, UK
| | - Jimi Wills
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, The University of Edinburgh, Western General Hospital Campus, Crewe Road, Edinburgh, EH4 2XU, Scotland, UK
| | - Julia R Dorin
- University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, Scotland, UK
| | - Richard Weller
- University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, Scotland, UK
| | - David J Clarke
- The EastChem School of Chemistry, University of Edinburgh, Joseph Black Building, Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Donald J Davidson
- University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, Scotland, UK
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6
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Liu CC, Lin MH. Hitchhiking motility of Staphylococcus aureus involves the interaction between its wall teichoic acids and lipopolysaccharide of Pseudomonas aeruginosa. Front Microbiol 2023; 13:1068251. [PMID: 36687638 PMCID: PMC9849799 DOI: 10.3389/fmicb.2022.1068251] [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: 10/12/2022] [Accepted: 12/13/2022] [Indexed: 01/07/2023] Open
Abstract
Staphylococcus aureus, which lacks pili and flagella, is nonmotile. However, it hitchhikes motile bacteria, such as Pseudomonas aeruginosa, to migrate in the environment. This study demonstrated that the hitchhiking motility of S. aureus SA113 was reduced after the tagO, which encodes an enzyme for wall teichoic acids (WTA) synthesis, was deleted. The hitchhiking motility was restored after the mutation was complemented by transforming a plasmid expressing TagO into the mutant. We also showed that adding purified lipopolysaccharide (LPS) to a culture that contains S. aureus SA113 and P. aeruginosa PAO1, reduced the movement of S. aureus, showing that WTA and LPS are involved in the hitchhiking motility of S. aureus. This study also found that P. aeruginosa promoted the movement of S. aureus in the digestive tract of Caenorhabditis elegans and in mice. In conclusion, this study reveals how S. aureus hitchhikes P. aeruginosa for translocation in an ecosystem. The results from this study improve our understanding on how a nonmotile pathogen moves in the environment and spreads in animals.
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Affiliation(s)
- Chao-Chin Liu
- 1Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Mei-Hui Lin
- 1Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan,2Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan,3Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan,*Correspondence: Mei-Hui Lin, ✉
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7
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Burian M, Wolz C, Yazdi AS. Transcriptional adaptation of staphylococci during colonization of the authentic human environment: An overview of transcriptomic changes and their relationship to physiological conditions. Front Cell Infect Microbiol 2022; 12:1062329. [PMID: 36467739 PMCID: PMC9712997 DOI: 10.3389/fcimb.2022.1062329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 11/02/2022] [Indexed: 12/06/2023] Open
Abstract
Staphylococci are commensals of human skin and mucous membranes, but some species can also cause serious infections. Host niches during both colonization and infection differ greatly and are characterized by specific environmental conditions (pH, temperature, oxygen, nutrient availability, and microbiota) that can affect gene expression and virulence of microbes. To successfully occupy extremely different habitats at different anatomical sites, Staphylococci are equipped with a variety of regulatory elements that allow specific adaptation to the changing environments. Not surprisingly, gene expression in vivo can be significantly different from the expression pattern observed in vitro. Niche specific stimuli that influence the bacterial ability to either cause infection or maintain colonization are only partially understood. Here, we describe habitat specific conditions and discuss the available literature analyzing staphylococcal gene expression, focusing on Staphylococcus aureus and S. epidermidis during colonization of the nose and skin.
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Affiliation(s)
- Marc Burian
- Department of Dermatology and Allergology, RWTH University Hospital Aachen, Aachen, Germany
| | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 “Controlling Microbes to Fight Infections”, University of Tübingen, Tübingen, Germany
| | - Amir S. Yazdi
- Department of Dermatology and Allergology, RWTH University Hospital Aachen, Aachen, Germany
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8
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The survival of epidemic and sporadic MRSA on human skin mimics is determined by both host and bacterial factors. Epidemiol Infect 2022; 150:e203. [PMID: 36382385 PMCID: PMC9987022 DOI: 10.1017/s0950268822001765] [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: 12/13/2022] Open
Abstract
Bacterial survival on, and interactions with, human skin may explain the epidemiological success of MRSA strains. We evaluated the bacterial counts for 27 epidemic and 31 sporadic MRSA strains on 3D epidermal models based on N/TERT cells (NEMs) after 1, 2 and 8 days. In addition, the expression of antimicrobial peptides (hBD-2, RNase 7), inflammatory cytokines (IL-1β, IL-6) and chemokine IL-8 by NEMs was assessed using immunoassays and the expression of 43 S. aureus virulence factors was determined by a multiplex competitive Luminex assay. To explore donor variation, bacterial counts for five epidemic and seven sporadic MRSA strains were determined on 3D primary keratinocyte models (LEMs) from three human donors. Bacterial survival was comparable on NEMs between the two groups, but on LEMs, sporadic strains showed significantly lower survival numbers compared to epidemic strains. Both groups triggered the expression of immune factors. Upon interaction with NEMs, only the epidemic MRSA strains expressed pore-forming toxins, including alpha-hemolysin (Hla), gamma-hemolysin (HlgB), Panton-Valentine leucocidin (LukS) and LukED. Together, these data indicate that the outcome of the interaction between MRSA and human skin mimics, depends on the unique combination of bacterial strain and host factors.
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9
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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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Costa FG, Horswill AR. Overcoming pH defenses on the skin to establish infections. PLoS Pathog 2022; 18:e1010512. [PMID: 35617212 PMCID: PMC9135183 DOI: 10.1371/journal.ppat.1010512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Skin health is influenced by the composition and integrity of the skin barrier. The healthy skin surface is an acidic, hypertonic, proteinaceous, and lipid-rich environment that microorganisms must adapt to for survival, and disruption of this environment can result in dysbiosis and increase risk for infectious diseases. This work provides a brief overview of skin barrier function and skin surface composition from the perspective of how the most common skin pathogen, Staphylococcus aureus, combats acid stress. Advancements in replicating this environment in the laboratory setting for the study of S. aureus pathogenesis on the skin, as well as future directions in this field, are also discussed.
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Affiliation(s)
- Flavia G. Costa
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- Department of Veterans Affairs, Eastern Colorado Healthcare System, Aurora, Colorado, United States of America
- * E-mail:
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11
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Teichmann P, Both A, Wolz C, Hornef MW, Rohde H, Yazdi AS, Burian M. The Staphylococcus epidermidis Transcriptional Profile During Carriage. Front Microbiol 2022; 13:896311. [PMID: 35558117 PMCID: PMC9087046 DOI: 10.3389/fmicb.2022.896311] [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: 03/14/2022] [Accepted: 04/08/2022] [Indexed: 11/29/2022] Open
Abstract
The virulence factors of the opportunistic human pathogen Staphylococcus epidermidis have been a main subject of research. In contrast, limited information is available on the mechanisms that allow the bacterium to accommodate to the conditions during carriage, a prerequisite for pathogenicity. Here, we tested the hypothesis that the adaptation of S. epidermidis at different anatomical sites is reflected by differential gene regulation. We used qPCR to profile S. epidermidis gene expression in vivo in nose and skin swabs of 11 healthy individuals. Despite some heterogeneity between individuals, significant site-specific differences were detected. For example, expression of the S. epidermidis regulator sarA was found similarly in the nose and on the skin of all individuals. Also, genes encoding colonization and immune evasion factors (sdrG, capC, and dltA), as well as the sphingomyelinase encoding gene sph, were expressed at both anatomical sites. In contrast, expression of the global regulator agr was almost inactive in the nose but readily present on the skin. A similar site-specific expression profile was also identified for the putative chitinase-encoding SE0760. In contrast, expression of the autolysine-encoding gene sceD and the wall teichoic acid (WTA) biosynthesis gene tagB were more pronounced in the nose as compared to the skin. In summary, our analysis identifies site-specific gene expression patterns of S. epidermidis during colonization. In addition, the observed expression signature was significantly different from growth in vitro. Interestingly, the strong transcription of sphingomyelinase together with the low expression of genes encoding the tricarboxylic acid cycle (TCA) suggests very good nutrient supply in both anatomical niches, even on the skin where one might have suspected a rather lower nutrient supply compared to the nose.
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Affiliation(s)
- Pascâl Teichmann
- Department of Dermatology and Allergology, RWTH University Hospital Aachen, Aachen, Germany
| | - Anna Both
- Institute of Medical Microbiology, Virology and Hygiene, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tuebingen, Tuebingen, Germany
| | - Mathias W Hornef
- Institute of Medical Microbiology, RWTH University Hospital Aachen, Aachen, Germany
| | - Holger Rohde
- Institute of Medical Microbiology, Virology and Hygiene, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Amir S Yazdi
- Department of Dermatology and Allergology, RWTH University Hospital Aachen, Aachen, Germany
| | - Marc Burian
- Department of Dermatology and Allergology, RWTH University Hospital Aachen, Aachen, Germany
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12
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Rapid Aggregation of Staphylococcus aureus in Synovial Fluid Is Influenced by Synovial Fluid Concentration, Viscosity, and Fluid Dynamics, with Evidence of Polymer Bridging. mBio 2022; 13:e0023622. [PMID: 35254134 PMCID: PMC9040867 DOI: 10.1128/mbio.00236-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Early bacterial survival in the postsurgical joint is still a mystery. Recently, synovial fluid-induced aggregation was proposed as a potential mechanism of bacterial protection upon entry into the joint. As synovial fluid is secreted back into the joint cavity following surgery, rapid fluctuations in synovial fluid concentrations, composition, and viscosity occur. These changes, along with fluid movement resulting from postoperative joint motion, modify the environment and potentially affect the kinetics of aggregate formation. Through this work, we sought to evaluate the influence of exposure time, synovial fluid concentration, viscosity, and fluid dynamics on aggregation. Furthermore, we aimed to elucidate the primary mechanism of aggregate formation by assessing the interaction of bacterial adhesins with the synovial fluid polymer fibrinogen. Following incubation under each simulated postoperative joint condition, the aggregates were imaged using confocal microscopy. Our analysis revealed the formation of two distinct aggregate phenotypes, depending on whether the incubation was conducted under static or dynamic conditions. Using a surface adhesin mutant, we have narrowed down the genetic determinants for synovial fluid aggregate formation and identified essential host polymers. We report here that synovial fluid-induced aggregation is influenced by various changes specific to the postsurgical joint environment. While we now have evidence that select synovial fluid polymers facilitate bridging aggregation through essential bacterial adhesins, we suspect that their utility is limited by the increasing viscosity under static conditions. Furthermore, dynamic fluid movement recovers the ability of the bacteria with surface proteins present to aggregate under high-viscosity conditions, yielding large, globular aggregates.
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