1
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Burke Ó, Zeden MS, O'Gara JP. The pathogenicity and virulence of the opportunistic pathogen Staphylococcus epidermidis. Virulence 2024; 15:2359483. [PMID: 38868991 DOI: 10.1080/21505594.2024.2359483] [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: 02/02/2024] [Accepted: 05/19/2024] [Indexed: 06/14/2024] Open
Abstract
The pervasive presence of Staphylococcus epidermidis and other coagulase-negative staphylococci on the skin and mucous membranes has long underpinned a casual disregard for the infection risk that these organisms pose to vulnerable patients in healthcare settings. Prior to the recognition of biofilm as an important virulence determinant in S. epidermidis, isolation of this microorganism in diagnostic specimens was often overlooked as clinically insignificant with potential delays in diagnosis and onset of appropriate treatment, contributing to the establishment of chronic infection and increased morbidity or mortality. While impressive progress has been made in our understanding of biofilm mechanisms in this important opportunistic pathogen, research into other virulence determinants has lagged S. aureus. In this review, the broader virulence potential of S. epidermidis including biofilm, toxins, proteases, immune evasion strategies and antibiotic resistance mechanisms is surveyed, together with current and future approaches for improved therapeutic interventions.
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Affiliation(s)
- Órla Burke
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | | | - James P O'Gara
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
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2
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Xu Z, Li Y, Xu A, Soteyome T, Yuan L, Ma Q, Seneviratne G, Li X, Liu J. Cell-wall-anchored proteins affect invasive host colonization and biofilm formation in Staphylococcus aureus. Microbiol Res 2024; 285:127782. [PMID: 38833832 DOI: 10.1016/j.micres.2024.127782] [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: 12/16/2023] [Revised: 05/21/2024] [Accepted: 05/21/2024] [Indexed: 06/06/2024]
Abstract
As a major human and animal pathogen, Staphylococcus aureus can attach to medical implants (abiotic surface) or host tissues (biotic surface), and further establish robust biofilms which enhances resistance and persistence to host immune system and antibiotics. Cell-wall-anchored proteins (CWAPs) covalently link to peptidoglycan, and largely facilitate the colonization of S. aureus on various surfaces (including adhesion and biofilm formation) and invasion into host cells (including adhesion, immune evasion, iron acquisition and biofilm formation). During biofilm formation, CWAPs function in adhesion, aggregation, collagen-like fiber network formation, and consortia formation. In this review, we firstly focus on the structural features of CWAPs, including their intracellular function and interactions with host cells, as well as the functions and ligand binding of CWAPs in different stages of S. aureus biofilm formation. Then, the roles of CWAPs in different biofilm processes with regards in development of therapeutic approaches are clarified, followed by the association between CWAPs genes and clonal lineages. By touching upon these aspects, we hope to provide comprehensive knowledge and clearer understanding on the CWAPs of S. aureus and their roles in biofilm formation, which may further aid in prevention and treatment infection and vaccine development.
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Affiliation(s)
- Zhenbo Xu
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Engineering Research Center of Starch and Vegetable Protein Processing Ministry of Education, South China University of Technology, Guangzhou 510640, China; Department of Laboratory Medicine, the Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China.
| | - Yaqin Li
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Engineering Research Center of Starch and Vegetable Protein Processing Ministry of Education, South China University of Technology, Guangzhou 510640, China
| | - Aijuan Xu
- Guangzhou Hybribio Medical Laboratory, Guangzhou 510730, China
| | - Thanapop Soteyome
- Home Economics Technology, Rajamangala University of Technology Phra Nakhon, Bangkok, Thailand
| | - Lei Yuan
- School of Food Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 225127, China
| | - Qin Ma
- Sericultural & Agri-Food Research Institute Guangdong Academy of Agricultural Sciences/Key Laboratory of Functional Foods, Ministry of Agriculture /Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, China
| | - Gamini Seneviratne
- National Institute of Fundamental Studies, Hantana road, Kandy, Sri Lanka
| | - Xuejie Li
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Engineering Research Center of Starch and Vegetable Protein Processing Ministry of Education, South China University of Technology, Guangzhou 510640, China.
| | - Junyan Liu
- College of Light Industry and Food Science, Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Academy of Contemporary Agricultural Engineering Innovations, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Key Laboratory of Green Processing and Intelligent Manufacturing of Lingnan Specialty Food, Ministry of Agriculture, Guangzhou 510225, China.
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3
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Bălașoiu (Jigău) RAC, Obistioiu D, Hulea A, Suleiman MA, Popescu I, Floares (Oarga) D, Imbrea IM, Neacșu AG, Șmuleac L, Pașcalău R, Crista L, Popescu CA, Samfira I, Imbrea F. Analysing the Antibacterial Synergistic Interactions of Romanian Lavender Essential Oils via Gas Chromatography-Mass Spectrometry: In Vitro and In Silico Approaches. PLANTS (BASEL, SWITZERLAND) 2024; 13:2136. [PMID: 39124254 PMCID: PMC11313841 DOI: 10.3390/plants13152136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Revised: 07/28/2024] [Accepted: 07/29/2024] [Indexed: 08/12/2024]
Abstract
This study investigated the phytochemical characteristics, antibacterial activity, and synergistic potential of essential oils derived from Romanian lavender. Gas Chromatography-Mass Spectrometry (GC/MS) analysis revealed that linalool is the main compound in all lavender essential oils, with concentrations ranging from 29.410% to 35.769%. Linalyl acetate was found in similar concentrations to linalool. Other significant compounds included 1,8-cineole (8.50%), lavandulyl acetate (5.38%), trans-β-ocimene (6.90%), and camphor (7.7%). A 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) test was used to assess antioxidant capacity, with substantial free-radical-scavenging activity shown in the IC50 values determined. The antibacterial efficacy of the oils was higher against Gram-positive bacteria than Gram-negative bacteria, with variations in minimum inhibitory concentrations (MICs), the extent of inhibition, and evolution patterns. The study also explored the oils' ability to enhance the efficacy of ampicillin, revealing synergistic interactions expressed as fractional inhibitory concentration indices. In silico protein-ligand docking studies used twenty-one compounds identified by GC-MS with bacterial protein targets, showing notable binding interactions with SasG (-6.3 kcal/mol to -4.6 kcal/mol) and KAS III (-6.2 kcal/mol to -4.9 kcal/mol). Overall, the results indicate that Romanian lavender essential oils possess potent antioxidant and antibacterial properties, and their synergistic interaction with ampicillin has potential for enhancing antibiotic therapies.
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Affiliation(s)
- Roxana Aurelia C. Bălașoiu (Jigău)
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Diana Obistioiu
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Anca Hulea
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Mukhtar Adeiza Suleiman
- Faculty of Life Science, Department of Biochemistry, Ahmadu Bello University, Zaria 810107, Nigeria;
| | - Iuliana Popescu
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Doris Floares (Oarga)
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Ilinca Merima Imbrea
- Faculty of Engineering and Applied Technologies, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania;
| | - Alina-Georgeta Neacșu
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Laura Șmuleac
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Raul Pașcalău
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Laura Crista
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Cosmin Alin Popescu
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Ionel Samfira
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
| | - Florin Imbrea
- Faculty of Agriculture, University of Life Sciences “King Michael I” from Timisoara, Calea Aradului 119, 300645 Timisoara, Romania; (R.A.C.B.); (A.H.); (I.P.); (D.F.); (A.-G.N.); (L.Ș.); (R.P.); (L.C.); (C.A.P.); (I.S.); (F.I.)
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Mills KB, Maciag JJ, Wang C, Crawford JA, Enroth TJ, Keim KC, Dufrêne YF, Robinson DA, Fey PD, Herr AB, Horswill AR. Staphylococcus aureus skin colonization is mediated by SasG lectin variation. Cell Rep 2024; 43:114022. [PMID: 38568806 DOI: 10.1016/j.celrep.2024.114022] [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] [Revised: 01/23/2024] [Accepted: 03/15/2024] [Indexed: 04/05/2024] Open
Abstract
Staphylococcus aureus causes the majority of skin and soft tissue infections, but this pathogen only transiently colonizes healthy skin. However, this transient skin exposure enables S. aureus to transition to infection. The initial adhesion of S. aureus to skin corneocytes is mediated by surface protein G (SasG). Here, phylogenetic analyses reveal the presence of two major divergent SasG alleles in S. aureus: SasG-I and SasG-II. Structural analyses of SasG-II identify a nonaromatic arginine in the binding pocket of the lectin subdomain that mediates adhesion to corneocytes. Atomic force microscopy and corneocyte adhesion assays indicate that SasG-II can bind to a broader variety of ligands than SasG-I. Glycosidase treatment results in different binding profiles between SasG-I and SasG-II on skin cells. In addition, SasG-mediated adhesion is recapitulated using differentiated N/TERT keratinocytes. Our findings indicate that SasG-II has evolved to adhere to multiple ligands, conferring a distinct advantage to S. aureus during skin colonization.
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Affiliation(s)
- Krista B Mills
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Joseph J Maciag
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Can Wang
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - John A Crawford
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Timothy J Enroth
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Klara C Keim
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - D Ashley Robinson
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS, USA; Center for Immunology and Microbial Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Andrew B Herr
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Veterans Affairs, VA Eastern Colorado Healthcare System, Aurora, CO, USA.
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5
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Liu S, Chen H, Xu F, Chen F, Yin Y, Zhang X, Tu S, Wang H. Unravelling staphylococcal small-colony variants in cardiac implantable electronic device infections: clinical characteristics, management, and genomic insights. Front Cell Infect Microbiol 2024; 13:1321626. [PMID: 38259974 PMCID: PMC10800868 DOI: 10.3389/fcimb.2023.1321626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Objectives Staphylococcal small-colony variants (SCVs) are common in cardiac implantable electronic device (CIED) infections. This is the first retrospective and multi-case study on CIED infections due to staphylococcal SCVs, aiming to provide a theoretical basis for the clinical management of CIED and device-related infections caused by staphylococcal SCVs. Methods Ninety patients with culture positive CIED infections were enrolled between 2021 and 2022. We compared the demographic and clinical characteristics of patients with and without SCVs and performed genomic studies on SCVs isolates. Results Compared to patients without SCVs, those with SCVs had a longer primary pacemaker implantation time and were more likely to have a history of device replacement and infection. They showed upregulated inflammatory indicators, especially higher NEUT% (52.6 vs. 26.8%, P = 0.032) and they had longer hospital stays (median 13 vs. 12 days, P = 0.012). Comparative genomics analysis was performed on Staphylococcus epidermidis wild-type and SCVs. Some genes were identified, including aap, genes encoding adhesin, CHAP domain-containing protein, LPXTG cell wall anchor domain-containing protein, and YSIRK-type signal peptide-containing protein. Conclusion Staphylococcal SCVs affect the clinical characteristics of CIED infections. The process of staphylococcal SCVs adherence, biofilm formation, and interaction with neutrophils play a vital role.
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Affiliation(s)
- Si Liu
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Hongbin Chen
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Fangjie Xu
- Department of Clinical Laboratory, Urumqi Friendship Hospital, Urumqi, China
| | - Fengning Chen
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Yuyao Yin
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Xiaoyang Zhang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Shangyu Tu
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
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Mills KB, Maciag JJ, Wang C, Crawford JA, Enroth TJ, Keim KC, Dufrêne YF, Robinson DA, Fey PD, Herr AB, Horswill AR. Staphylococcus aureus skin colonization is mediated by SasG lectin variation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567970. [PMID: 38045275 PMCID: PMC10690190 DOI: 10.1101/2023.11.20.567970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Staphylococcus aureus causes the majority of skin and soft tissue infections, but this pathogen only transiently colonizes healthy skin. However, this transient skin exposure enables S. aureus to transition to infection. Initial adhesion of S. aureus to skin corneocytes is mediated by surface protein G (SasG). Here, phylogenetic analyses reveal the presence of two major divergent SasG alleles in S. aureus, SasG-I and SasG-II. Structural analyses of SasG-II identified a unique non-aromatic arginine in the binding pocket of the lectin subdomain that mediates adhesion to corneocytes. Atomic force microscopy and corneocyte adhesion assays indicated SasG-II can bind to a broader variety of ligands than SasG-I. Glycosidase treatment resulted in different binding profiles between SasG-I and SasG-II on skin cells. Additionally, SasG-mediated adhesion was recapitulated using differentiated N/TERT keratinocytes. Our findings indicate that SasG-II has evolved to adhere to multiple ligands, conferring a distinct advantage to S. aureus during skin colonization.
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Affiliation(s)
- Krista B. Mills
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Joseph J. Maciag
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Can Wang
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - John A. Crawford
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Timothy J. Enroth
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Klara C. Keim
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - D. Ashley Robinson
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS, USA
- Center for Immunology and Microbial Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Paul D. Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Andrew B. Herr
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Division of Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Veterans Affairs, VA Eastern Colorado Healthcare System, Aurora, CO, USA
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7
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Burke TL, Rupp ME, Fey PD. Staphylococcus epidermidis. Trends Microbiol 2023; 31:763-764. [PMID: 36682998 DOI: 10.1016/j.tim.2023.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 01/21/2023]
Affiliation(s)
- Taylor L Burke
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - M E Rupp
- Department of Internal Medicine, Division of Infectious Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - P D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA.
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8
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Yadav R, Shaikh T, Tikole S, Herr AB, Fitzkee NC. 1H, 15N, and 13C chemical shift backbone resonance NMR assignment of the accumulation-associated protein (Aap) lectin domain from Staphylococcus epidermidis. BIOMOLECULAR NMR ASSIGNMENTS 2023; 17:95-99. [PMID: 37022616 PMCID: PMC10247473 DOI: 10.1007/s12104-023-10126-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 03/30/2023] [Indexed: 06/02/2023]
Abstract
Staphylococcus epidermidis is the leading causative agent for hospital-acquired infections, especially device-related infections, due to its ability to form biofilms. The accumulation-associated protein (Aap) of S. epidermidis is primarily responsible for biofilm formation and consists of two domains, A and B. It was found that the A domain is responsible for the attachment to the abiotic/biotic surface, whereas the B domain is responsible for the accumulation of bacteria during biofilm formation. One of the parts of the A domain is the Aap lectin, which is a carbohydrate-binding domain having 222 amino acids in its structure. Here we report the near complete backbone chemical shift assignments for the lectin domain, as well as its predicted secondary structure. This data will provide a platform for future NMR studies to explore the role of lectin in biofilm formation.
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Affiliation(s)
- Rahul Yadav
- Department of Chemistry, Mississippi State University, Starkville, MS, 39762, USA
- Physical Sciences Department, University of Arkansas, Ft. Smith, AR, 72913, USA
| | - Tanveer Shaikh
- Department of Chemistry, Mississippi State University, Starkville, MS, 39762, USA
| | - Suhas Tikole
- Department of Chemistry, Mississippi State University, Starkville, MS, 39762, USA
| | - Andrew B Herr
- Department of Pediatrics, Division of Immunobiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, OH, 45229, USA
| | - Nicholas C Fitzkee
- Department of Chemistry, Mississippi State University, Starkville, MS, 39762, USA.
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Clark LC, Atkin KE, Whelan F, Brentnall AS, Harris G, Towell AM, Turkenburg JP, Liu Y, Feizi T, Griffiths SC, Geoghegan JA, Potts JR. Staphylococcal Periscope proteins Aap, SasG, and Pls project noncanonical legume-like lectin adhesin domains from the bacterial surface. J Biol Chem 2023; 299:102936. [PMID: 36702253 PMCID: PMC9999234 DOI: 10.1016/j.jbc.2023.102936] [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: 11/13/2022] [Revised: 01/08/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
Staphylococcus aureus and Staphylococcus epidermidis are frequently associated with medical device infections that involve establishment of a bacterial biofilm on the device surface. Staphylococcal surface proteins Aap, SasG, and Pls are members of the Periscope Protein class and have been implicated in biofilm formation and host colonization; they comprise a repetitive region ("B region") and an N-terminal host colonization domain within the "A region," predicted to be a lectin domain. Repetitive E-G5 domains (as found in Aap, SasG, and Pls) form elongated "stalks" that would vary in length with repeat number, resulting in projection of the N-terminal A domain variable distances from the bacterial cell surface. Here, we present the structures of the lectin domains within A regions of SasG, Aap, and Pls and a structure of the Aap lectin domain attached to contiguous E-G5 repeats, suggesting the lectin domains will sit at the tip of the variable length rod. We demonstrate that these isolated domains (Aap, SasG) are sufficient to bind to human host desquamated nasal epithelial cells. Previously, proteolytic cleavage or a deletion within the A domain had been reported to induce biofilm formation; the structures suggest a potential link between these observations. Intriguingly, while the Aap, SasG, and Pls lectin domains bind a metal ion, they lack the nonproline cis peptide bond thought to be key for carbohydrate binding by the lectin fold. This suggestion of noncanonical ligand binding should be a key consideration when investigating the host cell interactions of these bacterial surface proteins.
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Affiliation(s)
- Laura C Clark
- Department of Biology, University of York, York, United Kingdom
| | - Kate E Atkin
- Department of Biology, University of York, York, United Kingdom
| | - Fiona Whelan
- Department of Biology, University of York, York, United Kingdom; Department of Molecular and Biomedical Science, School of Biological Sciences, University of Adelaide, South Australia, Australia.
| | | | - Gemma Harris
- Department of Biology, University of York, York, United Kingdom
| | - Aisling M Towell
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | | | - Yan Liu
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Ten Feizi
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom
| | | | - Joan A Geoghegan
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland; Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Jennifer R Potts
- Department of Biology, University of York, York, United Kingdom; School of Life and Environmental Sciences, University of Sydney, New South Wales, Australia.
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10
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Staphylococcus epidermidis and its dual lifestyle in skin health and infection. Nat Rev Microbiol 2023; 21:97-111. [PMID: 36042296 PMCID: PMC9903335 DOI: 10.1038/s41579-022-00780-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2022] [Indexed: 01/20/2023]
Abstract
The coagulase-negative bacterium Staphylococcus epidermidis is a member of the human skin microbiota. S. epidermidis is not merely a passive resident on skin but actively primes the cutaneous immune response, maintains skin homeostasis and prevents opportunistic pathogens from causing disease via colonization resistance. However, it is now appreciated that S. epidermidis and its interactions with the host exist on a spectrum of potential pathogenicity derived from its high strain-level heterogeneity. S. epidermidis is the most common cause of implant-associated infections and is a canonical opportunistic biofilm former. Additional emerging evidence suggests that some strains of S. epidermidis may contribute to the pathogenesis of common skin diseases. Here, we highlight new developments in our understanding of S. epidermidis strain diversity, skin colonization dynamics and its multifaceted interactions with the host and other members of the skin microbiota.
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Maciag JJ, Chantraine C, Mills KB, Yadav R, Yarawsky AE, Chaton CT, Vinod D, Fitzkee NC, Mathelié-Guinlet M, Dufrêne YF, Fey PD, Horswill AR, Herr AB. Mechanistic basis of staphylococcal interspecies competition for skin colonization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525635. [PMID: 36747832 PMCID: PMC9900903 DOI: 10.1101/2023.01.26.525635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Staphylococci, whether beneficial commensals or pathogens, often colonize human skin, potentially leading to competition for the same niche. In this multidisciplinary study we investigate the structure, binding specificity, and mechanism of adhesion of the Aap lectin domain required for Staphylococcus epidermidis skin colonization and compare its characteristics to the lectin domain from the orthologous Staphylococcus aureus adhesin SasG. The Aap structure reveals a legume lectin-like fold with atypical architecture, showing specificity for N-acetyllactosamine and sialyllactosamine. Bacterial adhesion assays using human corneocytes confirmed the biological relevance of these Aap-glycan interactions. Single-cell force spectroscopy experiments measured individual binding events between Aap and corneocytes, revealing an extraordinarily tight adhesion force of nearly 900 nN and a high density of receptors at the corneocyte surface. The SasG lectin domain shares similar structural features, glycan specificity, and corneocyte adhesion behavior. We observe cross-inhibition of Aap-and SasG-mediated staphylococcal adhesion to corneocytes. Together, these data provide insights into staphylococcal interspecies competition for skin colonization and suggest potential avenues for inhibition of S. aureus colonization.
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Affiliation(s)
- Joseph J. Maciag
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Constance Chantraine
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Krista B. Mills
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Rahul Yadav
- Department of Chemistry, Mississippi State University, Mississippi State, MS
| | - Alexander E. Yarawsky
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Catherine T. Chaton
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Divya Vinod
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
- Medical Sciences Undergraduate Program, University of Cincinnati, Cincinnati, OH
| | - Nicholas C. Fitzkee
- Department of Chemistry, Mississippi State University, Mississippi State, MS
| | - Marion Mathelié-Guinlet
- Institut de Chimie et Biologie des Membranes et des Nano-Objets, CNRS UMR 5248, University of Bordeaux, Pessac, France
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Paul D. Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Andrew B. Herr
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
- Division of Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
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Yarawsky AE, Ori AL, English LR, Whitten ST, Herr AB. Convergent behavior of extended stalk regions from staphylococcal surface proteins with widely divergent sequence patterns. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.06.523059. [PMID: 36711672 PMCID: PMC9881980 DOI: 10.1101/2023.01.06.523059] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Staphylococcus epidermidis and S. aureus are highly problematic bacteria in hospital settings. This stems, at least in part, from strong abilities to form biofilms on abiotic or biotic surfaces. Biofilms are well-organized multicellular aggregates of bacteria, which, when formed on indwelling medical devices, lead to infections that are difficult to treat. Cell wall-anchored (CWA) proteins are known to be important players in biofilm formation and infection. Many of these proteins have putative stalk-like regions or regions of low complexity near the cell wall-anchoring motif. Recent work demonstrated the strong propensity of the stalk region of the S. epidermidis accumulation-associated protein (Aap) to remain highly extended under solution conditions that typically induce compaction or other significant conformational changes. This behavior is consistent with the expected function of a stalk-like region that is covalently attached to the cell wall peptidoglycan and projects the adhesive domains of Aap away from the cell surface. In this study, we evaluate whether the ability to resist compaction is a common theme among stalk regions from various staphylococcal CWA proteins. Circular dichroism spectroscopy was used to examine secondary structure changes as a function of temperature and cosolvents along with sedimentation velocity analytical ultracentrifugation and SAXS to characterize structural characteristics in solution. All stalk regions tested are intrinsically disordered, lacking secondary structure beyond random coil and polyproline type II helix, and they all sample highly extended conformations. Remarkably, the Ser-Asp dipeptide repeat region of SdrC exhibited nearly identical behavior in solution when compared to the Aap Pro/Gly-rich region, despite highly divergent sequence patterns, indicating conservation of function by various distinct staphylococcal CWA protein stalk regions.
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Affiliation(s)
- Alexander E. Yarawsky
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Andrea L. Ori
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA,Medical Sciences Baccalaureate Program, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Lance R. English
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Steven T. Whitten
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Andrew B. Herr
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA,Division of Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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Staphylococcal Corneocyte Adhesion: Assay Optimization and Roles of Aap and SasG Adhesins in the Establishment of Healthy Skin Colonization. Microbiol Spectr 2022; 10:e0246922. [PMID: 36219106 PMCID: PMC9769725 DOI: 10.1128/spectrum.02469-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen that causes the majority of wound and soft tissue infections. The accumulation-associated protein (Aap) from S. epidermidis and surface protein G (SasG) from S. aureus are cell wall-anchored (CWA) proteins known to be important in adhesion to healthy corneocytes from human skin. We investigated the mechanisms by which S. aureus colonizes healthy human skin by developing an optimized corneocyte adhesion assay. Trypan blue was used for enhanced red autofluorescent visualization of corneocytes with an overlay of green-fluorescent bacteria. The percent area of bacterial adhesion for images acquired by a fluorescence microscope was quantified using Fiji ImageJ. Using this optimized imaging procedure, differences in adhesion between various species and strains of staphylococci were measured. The ability of purified SasG to reduce Staphylococcus epidermidis adhesion was investigated in order to determine if these CWA proteins can compete for binding sites. To further test CWA-mediated adhesion, we engineered a nonadhering S. carnosus strain to express full-length SasG from two methicillin-resistant S. aureus (MRSA) strains. Finally, we demonstrated that the SasG A domain was a critical region of this surface protein for adherence to healthy human corneocytes. The developed imaging and expression methods are useful for studying staphylococcal adhesion to healthy human skin and have the potential to be used with a wide variety of fluorescently labeled organisms on both healthy and disease-state (such as atopic dermatitis) corneocytes. IMPORTANCE The skin is the largest organ of the human body and acts as a shield against hazards such as harmful bacteria like Staphylococcus aureus. A diverse skin microbiota and immune cross talk control S. aureus numbers. S. aureus can bind to healthy skin and subsequently proliferate when the skin barrier is compromised, such as in a wound or in patients with atopic dermatitis (AD). It is important to understand these mechanisms in an effort to prevent pathogenic bacteria from causing infection. We describe an augmented corneocyte adhesion assay using fluorescence microscopy to study binding of various staphylococcal species to healthy human skin cells. In addition, we tested the ability of homologous proteins from different staphylococcal species to reduce binding, and developed a new S. carnosus expression system to test individual protein binding properties. Our newly developed methods and findings will enhance the understanding of how staphylococci bind to healthy human skin.
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Wang C, Chantraine C, Viljoen A, Herr AB, Fey PD, Horswill AR, Mathelié-Guinlet M, Dufrêne YF. The staphylococcal biofilm protein Aap mediates cell-cell adhesion through mechanically distinct homophilic and lectin interactions. PNAS NEXUS 2022; 1:pgac278. [PMID: 36712378 PMCID: PMC9802226 DOI: 10.1093/pnasnexus/pgac278] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 12/01/2022] [Indexed: 12/04/2022]
Abstract
The accumulation phase of staphylococcal biofilms relies on both the production of an extracellular polysaccharide matrix and the expression of bacterial surface proteins. A prototypical example of such adhesive proteins is the long multidomain protein Aap (accumulation-associated protein) from Staphylococcus epidermidis, which mediates zinc-dependent homophilic interactions between Aap B-repeat regions through molecular forces that have not been investigated yet. Here, we unravel the remarkable mechanical strength of single Aap-Aap homophilic bonds between living bacteria and we demonstrate that intercellular adhesion also involves sugar binding through the lectin domain of the Aap A region. We find that the mechanical force needed to unfold individual β-sheet-rich G5-E domains from the Aap B-repeat regions is very high, ranging from 300 up to 1,000 pN at high loading rates, indicating these are extremely stable. This high mechanostability provides a means to the cells to form highly adhesive and cohesive biofilms capable of sustaining high physiological shear stress. Importantly, we identify a previously undescribed role of Aap in bacterial-bacterial adhesion, that is, heterophilic sugar binding by a specific lectin domain located in the N-terminal A region, which might be important to establish initial contacts between cells before strong homophilic bonds come into play. This study emphasizes the remarkable mechanical and binding properties of Aap as well as its wide diversity of adhesive functions.
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Affiliation(s)
| | | | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Andrew B Herr
- Divisions of Immunobiology and Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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Yarawsky AE, Hopkins JB, Chatzimagas L, Hub JS, Herr AB. Solution Structural Studies of Pre-amyloid Oligomer States of the Biofilm Protein Aap. J Mol Biol 2022; 434:167708. [PMID: 35777467 PMCID: PMC9615840 DOI: 10.1016/j.jmb.2022.167708] [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: 05/11/2022] [Revised: 06/20/2022] [Accepted: 06/25/2022] [Indexed: 11/16/2022]
Abstract
Staphylococcus epidermidis is a commensal bacterium on human skin that is also the leading cause of medical device-related infections. The accumulation-associated protein (Aap) from S. epidermidis is a critical factor for infection via its ability to mediate biofilm formation. The B-repeat superdomain of Aap is composed of 5 to 17 Zn2+-binding B-repeats, which undergo rapid, reversible assembly to form dimer and tetramer species. The tetramer can then undergo a conformational change and nucleate highly stable functional amyloid fibrils. In this study, multiple techniques including analytical ultracentrifugation (AUC) and small-angle X-ray scattering (SAXS) are used to probe a panel of B-repeat mutant constructs that assemble to distinct oligomeric states to define the structural characteristics of B-repeat dimer and tetramer species. The B-repeat region from Aap forms an extremely elongated conformation that presents several challenges for standard SAXS analyses. Specialized approaches, such as cross-sectional analyses, allowed for in-depth interpretation of data, while explicit-solvent calculations via WAXSiS allowed for accurate evaluation of atomistic models. The resulting models suggest mechanisms by which Aap functional amyloid fibrils form, illuminating an important contributing factor to recurrent staphylococcal infections.
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Affiliation(s)
- Alexander E Yarawsky
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jesse B Hopkins
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL, USA
| | - Leonie Chatzimagas
- Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany
| | - Jochen S Hub
- Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany
| | - Andrew B Herr
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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Cai Z, Mo Z, Zheng S, Lan S, Xie S, Lu J, Tang C, Shen Z. Flavaspidic acid BB combined with mupirocin improves its anti-bacterial and anti-biofilm activities against Staphylococcus epidermidis. BMC Microbiol 2022; 22:179. [PMID: 35840879 PMCID: PMC9284735 DOI: 10.1186/s12866-022-02578-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 06/06/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND The increase in drug-resistant opportunistic pathogenic bacteria, especially of antibiotic-resistant Staphylococcus epidermidis (S. epidermidis), has led to difficulties in the treatment of skin and soft tissue infections (SSTI). The major reason for bacterial resistance is the formation of bacterial biofilm. Here, we report a promising combination therapy of flavaspidic acid BB (BB) and mupirocin, which can effectively eradicate the biofilm of S. epidermidis and eliminate its drug resistance. RESULT The susceptibility test showed that the combination of BB and mupirocin has good antibacterial and antibiofilm activities, and the fractional inhibitory concentration index (FICI) of BB combined with mupirocin was 0.51 ± 0.00 ~ 0.75 ± 0.05, showing synergistic effect. Moreover, the time-kill curve assay results indicated that the combination of drugs can effectively inhibit the planktonic S. epidermidis. After drugs treatment, the drug-combination showed significantly inhibitory effects on the metabolic activity and total biomass in each stage of biofilm formation. The synergistic effect is likely related to the adhesion between bacteria, which is confirmed by field emission scanning electron microscope. And the expression level of aap, sarA and agrA genes were detected by real-time quantitative PCR (qRT-PCR). CONCLUSION Our study provides the experimental data for the use of BB for the clinical treatment of skin infections and further demonstrate the potential of BB as a novel biofilm inhibitor.
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Affiliation(s)
- Zhiling Cai
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
| | - Zitong Mo
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
| | - Shiqian Zheng
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
| | - Shihua Lan
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
| | - Shengjun Xie
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
| | - Jinghui Lu
- The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, China
| | - Chunping Tang
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
| | - Zhibin Shen
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China.
- Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System, Guangdong Pharmaceutical University, Guangzhou, China.
- Guangdong Cosmetics Engineering &Technology Research Center, Guangdong Pharmaceutical University, Guangzhou, China.
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Fibronectin binding protein B binds to loricrin and promotes corneocyte adhesion by Staphylococcus aureus. Nat Commun 2022; 13:2517. [PMID: 35523796 PMCID: PMC9076634 DOI: 10.1038/s41467-022-30271-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 04/19/2022] [Indexed: 12/23/2022] Open
Abstract
Colonisation of humans by Staphylococcus aureus is a major risk factor for infection, yet the bacterial and host factors involved are not fully understood. The first step during skin colonisation is adhesion of the bacteria to corneocytes in the stratum corneum where the cornified envelope protein loricrin is the main ligand for S. aureus. Here we report a novel loricrin-binding protein of S. aureus, the cell wall-anchored fibronectin binding protein B (FnBPB). Single-molecule force spectroscopy revealed both weak and ultra-strong (2 nN) binding of FnBPB to loricrin and that mechanical stress enhanced the strength of these bonds. Treatment with a peptide derived from fibrinogen decreased the frequency of strong interactions, suggesting that both ligands bind to overlapping sites within FnBPB. Finally, we show that FnBPB promotes adhesion to human corneocytes by binding strongly to loricrin, highlighting the relevance of this interaction to skin colonisation. The first step during skin colonization by is its adhesion to corneocytes. Da Costa et al. show that the cell wall-anchored fibronectin binding protein B (FnBPB) of S. aureus binds to loricrin. Applying single cell force spectroscopy, they demonstrate that this interaction promotes adhesion of S. aureus to human corneocytes.
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Aubourg M, Pottier M, Léon A, Bernay B, Dhalluin A, Cacaci M, Torelli R, Ledormand P, Martini C, Sanguinetti M, Auzou M, Gravey F, Giard JC. Inactivation of the Response Regulator AgrA Has a Pleiotropic Effect on Biofilm Formation, Pathogenesis and Stress Response in Staphylococcus lugdunensis. Microbiol Spectr 2022; 10:e0159821. [PMID: 35138170 PMCID: PMC8826819 DOI: 10.1128/spectrum.01598-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/07/2022] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus lugdunensis is a coagulase-negative Staphylococcus that emerges as an important opportunistic pathogen. However, little is known about the regulation underlying the transition from commensal to virulent state. Based on knowledge of S. aureus virulence, we suspected that the agr quorum sensing system may be an important determinant for the pathogenicity of S. lugdunensis. We investigated the functions of the transcriptional regulator AgrA using the agrA deletion mutant. AgrA played a role in cell pigmentation: ΔargA mutant colonies were white while the parental strains were slightly yellow. Compared with the wild-type strain, the ΔargA mutant was affected in its ability to form biofilm and was less able to survive in mice macrophages. Moreover, the growth of ΔagrA was significantly reduced by the addition of 10% NaCl or 0.4 mM H2O2 and its survival after 2 h in the presence of 1 mM H2O2 was more than 10-fold reduced. To explore the mechanisms involved beyond these phenotypes, the ΔagrA proteome and transcriptome were characterized by mass spectrometry and RNA-Seq. We found that AgrA controlled several virulence factors as well as stress-response factors, which are well correlated with the reduced resistance of the ΔagrA mutant to osmotic and oxidative stresses. These results were not the consequence of the deregulation of RNAIII of the agr system, since no phenotype or alteration of the proteomic profile has been observed for the ΔRNAIII mutant. Altogether, our results highlighted that the AgrA regulator of S. lugdunensis played a key role in its ability to become pathogenic. IMPORTANCE Although belonging to the natural human skin flora, Staphylococcus lugdunensis is recognized as a particularly aggressive and destructive pathogen. This study aimed to characterize the role of the response regulator AgrA, which is a component of the quorum-sensing agr system and known to be a major element in the regulation of pathogenicity and biofilm formation in Staphylococcus aureus. In the present study, we showed that, contrary to S. aureus, the agrA deletion mutant produced less biofilm. Inactivation of agrA conferred a white colony phenotype and impacted S. lugdunensis in its ability to survive in mice macrophages and to cope with osmotic and oxidative stresses. By global proteomic and transcriptomic approaches, we identified the AgrA regulon, bringing molecular bases underlying the observed phenotypes. Together, our data showed the importance of AgrA in the opportunistic pathogenic behavior of S. lugdunensis allowing it to be considered as an interesting therapeutic target.
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Affiliation(s)
- Marion Aubourg
- Université de Caen Normandie, Dynamicure, INSERM U1311, CHU de Caen, Caen, France
| | - Marine Pottier
- Université de Caen Normandie, Dynamicure, INSERM U1311, CHU de Caen, Caen, France
- LABÉO Frank Duncombe, Caen, France
| | - Albertine Léon
- Université de Caen Normandie, Dynamicure, INSERM U1311, CHU de Caen, Caen, France
- LABÉO Frank Duncombe, Caen, France
| | - Benoit Bernay
- Plateforme Proteogen SFR ICORE 4206, Université de Caen Normandie, Caen, France
| | - Anne Dhalluin
- Université de Caen Normandie, Dynamicure, INSERM U1311, CHU de Caen, Caen, France
| | - Margherita Cacaci
- Institute of Microbiology, Catholic University of Sacred Heart, L. go F. Vito 1, Rome, Italy
| | - Riccardo Torelli
- Institute of Microbiology, Catholic University of Sacred Heart, L. go F. Vito 1, Rome, Italy
| | | | - Cecilia Martini
- Institute of Microbiology, Catholic University of Sacred Heart, L. go F. Vito 1, Rome, Italy
| | - Maurizio Sanguinetti
- Institute of Microbiology, Catholic University of Sacred Heart, L. go F. Vito 1, Rome, Italy
| | - Michel Auzou
- CHU de Caen, Laboratoire de Microbiologie, Caen, France
| | - François Gravey
- Université de Caen Normandie, Dynamicure, INSERM U1311, CHU de Caen, Caen, France
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Abstract
The stratum corneum is the outermost layer of the epidermis and is thus directly exposed to the environment. It consists mainly of corneocytes, which are keratinocytes in the last stage of differentiation, having neither nuclei nor organelles. However, they retain keratin filaments embedded in filaggrin matrix and possess a lipid envelope which protects the body from desiccation. Despite the desiccated, nutrient-poor, and acidic nature of the skin making it a hostile environment for most microorganisms, this organ is colonized by commensal microbes. Among the classic skin commensals are Propionibacterium acnes and coagulase-negative staphylococci (CoNS) with Staphylococcus epidermidis as a leading species. An as-yet-unanswered question is what enables S. epidermis to colonize skin so successfully. In their recent article, P. D. Fey and his colleagues (P. Roy, A. R. Horswill, and P. D. Fey, mBio 12:e02908-20, 2021, https://doi.org/10.1128/mBio.02908-20) have brought us one step closer to answering this question.
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