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Pellegrini A, Motta C, Bellan Menegussi E, Pierangelini A, Viglio S, Coppolino F, Beninati C, De Filippis V, Barbieri G, Pietrocola G. The serine-rich repeat glycoprotein Srr2 mediates Streptococcus agalactiae interaction with host fibronectin. BMC Microbiol 2024; 24:221. [PMID: 38909237 PMCID: PMC11193222 DOI: 10.1186/s12866-024-03374-6] [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: 02/29/2024] [Accepted: 06/17/2024] [Indexed: 06/24/2024] Open
Abstract
BACKGROUND Group B Streptococcus (GBS) is a commensal of healthy adults and an important pathogen in newborns, the elderly and immunocompromised individuals. GBS displays several virulence factors that promote colonisation and host infection, including the ST-17 strain-specific adhesin Srr2, previously characterised for its binding to fibrinogen. Another common target for bacterial adhesins and for host colonization is fibronectin, a multi-domain glycoprotein found ubiquitously in body fluids, in the extracellular matrix and on the surface of cells. RESULTS In this study, fibronectin was identified as a novel ligand for the Srr2 adhesin of GBS. A derivative of the ST-17 strain BM110 overexpressing the srr2 gene showed an increased ability to bind fibrinogen and fibronectin, compared to the isogenic wild-type strain. Conversely, the deletion of srr2 impaired bacterial adhesion to both ligands. ELISA assays and surface plasmon resonance studies using the recombinant binding region (BR) form of Srr2 confirmed a direct interaction with fibronectin with an estimated Kd of 92 nM. Srr2-BR variants defective in fibrinogen binding also exhibited no interaction with fibronectin, suggesting that Srr2 binds this ligand through the dock-lock-latch mechanism, previously described for fibrinogen binding. The fibronectin site responsible for recombinant Srr2-BR binding was identified and localised in the central cell-binding domain of the protein. Finally, in the presence of fibronectin, the ability of a Δsrr2 mutant to adhere to human cervico-vaginal epithelial cells was significantly lower than that of the wild-type strain. CONCLUSION By combining genetic and biochemical approaches, we demonstrate a new role for Srr2, namely interacting with fibronectin. We characterised the molecular mechanism of this interaction and demonstrated that it plays a role in promoting the adhesion of GBS to human cervico-vaginal epithelial cells, further substantiating the role of Srr2 as a factor responsible for the hypervirulence of GBS ST-17 strains. The discovery of the previously undescribed interaction between Srr2 and fibronectin establishes this adhesin as a key factor for GBS colonisation of host tissues.
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Affiliation(s)
| | - Chiara Motta
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | | | - Andrea Pierangelini
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Simona Viglio
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Francesco Coppolino
- Department of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Concetta Beninati
- Department of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Vincenzo De Filippis
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Giulia Barbieri
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
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2
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Goh KGK, Desai D, Thapa R, Prince D, Acharya D, Sullivan MJ, Ulett GC. An opportunistic pathogen under stress: how Group B Streptococcus responds to cytotoxic reactive species and conditions of metal ion imbalance to survive. FEMS Microbiol Rev 2024; 48:fuae009. [PMID: 38678005 PMCID: PMC11098048 DOI: 10.1093/femsre/fuae009] [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: 08/31/2023] [Revised: 03/26/2024] [Accepted: 04/16/2024] [Indexed: 04/29/2024] Open
Abstract
Group B Streptococcus (GBS; also known as Streptococcus agalactiae) is an opportunistic bacterial pathogen that causes sepsis, meningitis, pneumonia, and skin and soft tissue infections in neonates and healthy or immunocompromised adults. GBS is well-adapted to survive in humans due to a plethora of virulence mechanisms that afford responses to support bacterial survival in dynamic host environments. These mechanisms and responses include counteraction of cell death from exposure to excess metal ions that can cause mismetallation and cytotoxicity, and strategies to combat molecules such as reactive oxygen and nitrogen species that are generated as part of innate host defence. Cytotoxicity from reactive molecules can stem from damage to proteins, DNA, and membrane lipids, potentially leading to bacterial cell death inside phagocytic cells or within extracellular spaces within the host. Deciphering the ways in which GBS responds to the stress of cytotoxic reactive molecules within the host will benefit the development of novel therapeutic and preventative strategies to manage the burden of GBS disease. This review summarizes knowledge of GBS carriage in humans and the mechanisms used by the bacteria to circumvent killing by these important elements of host immune defence: oxidative stress, nitrosative stress, and stress from metal ion intoxication/mismetallation.
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Affiliation(s)
- Kelvin G K Goh
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Devika Desai
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Ruby Thapa
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Darren Prince
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Dhruba Acharya
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Matthew J Sullivan
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom
| | - Glen C Ulett
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
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3
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Ling J, Hryckowian AJ. Re-framing the importance of Group B Streptococcus as a gut-resident pathobiont. Infect Immun 2024:e0047823. [PMID: 38436256 DOI: 10.1128/iai.00478-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024] Open
Abstract
Streptococcus agalactiae (Group B Streptococcus, GBS) is a Gram-positive bacterial species that causes disease in humans across the lifespan. While antibiotics are used to mitigate GBS infections, it is evident that antibiotics disrupt human microbiomes (which can predispose people to other diseases later in life), and antibiotic resistance in GBS is on the rise. Taken together, these unintended negative impacts of antibiotics highlight the need for precision approaches for minimizing GBS disease. One possible approach involves selectively depleting GBS in its commensal niches before it can cause disease at other body sites or be transmitted to at-risk individuals. One understudied commensal niche of GBS is the adult gastrointestinal (GI) tract, which may predispose colonization at other body sites in individuals at risk for GBS disease. However, a better understanding of the host-, microbiome-, and GBS-determined variables that dictate GBS GI carriage is needed before precise GI decolonization approaches can be developed. In this review, we synthesize current knowledge of the diverse body sites occupied by GBS as a pathogen and as a commensal. We summarize key molecular factors GBS utilizes to colonize different host-associated niches to inform future efforts to study GBS in the GI tract. We also discuss other GI commensals that are pathogenic in other body sites to emphasize the broader utility of precise de-colonization approaches for mitigating infections by GBS and other bacterial pathogens. Finally, we highlight how GBS treatments could be improved with a more holistic understanding of GBS enabled by continued GI-focused study.
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Affiliation(s)
- Joie Ling
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Healthon, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Andrew J Hryckowian
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Healthon, Madison, Wisconsin, USA
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4
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Thomas LS, Faiola NA, Canessa E, Hathout Y, Cook LC. In silico and experimental analysis of the repeated domains in BvaP, a protein important for GBS vaginal colonization. Infect Immun 2023; 91:e0038723. [PMID: 37916807 PMCID: PMC10714994 DOI: 10.1128/iai.00387-23] [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: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 11/03/2023] Open
Abstract
Streptococcus agalactiae (group B strep, GBS) infections in neonates are often fatal and strongly associated with maternal GBS vaginal colonization. Previously, we highlighted the importance of a formerly uncharacterized protein, BvaP, in GBS vaginal colonization. BvaP is highly conserved across GBS and is made up of repeated domains, with a variable number of repeats between strains. Here, we evaluate the prevalence of BvaP repeated domains and their relevance in phenotypes previously associated with vaginal colonization. Using in silico analysis, we found that the number of repeats in the BvaP protein does not generally appear to be associated with serotype, isolation site, or host. Using BvaP truncations in GBS strain A909, we determined that a smaller number of repeats was correlated with decreased bacterial chain length, but adherence to vaginal epithelial cells was complemented using BvaP containing one, two, three, or five repeats. Future research will be geared toward understanding the host immune response to BvaP in vivo and whether vaginal carriage or host response is dependent on the BvaP repeated domains.
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Affiliation(s)
- Lamar S. Thomas
- Department of Biology, Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Nicholas A. Faiola
- Department of Biology, Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Emily Canessa
- School of Pharmacy and Pharmaceutical Sciences, Binghamton University, Binghamton, New York, USA
| | - Yetrib Hathout
- School of Pharmacy and Pharmaceutical Sciences, Binghamton University, Binghamton, New York, USA
| | - Laura C. Cook
- Department of Biology, Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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5
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A Novel Conserved Protein in Streptococcus agalactiae, BvaP, Is Important for Vaginal Colonization and Biofilm Formation. mSphere 2022; 7:e0042122. [PMID: 36218343 PMCID: PMC9769775 DOI: 10.1128/msphere.00421-22] [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] [Indexed: 01/13/2023] Open
Abstract
Streptococcus agalactiae (group B streptococcus [GBS]) infections in neonates are often fatal and strongly associated with maternal GBS vaginal colonization. Here, we investigated the role of an uncharacterized protein, BvaP, in GBS vaginal colonization. bvaP was previously identified as the most highly upregulated gene in the GBS A909 transcriptome when comparing vaginal colonization to growth in liquid culture. We found that the absence of BvaP affects the ability of GBS to adhere to extracellular matrix components and human vaginal epithelial cells, and the ability of a ΔbvaP mutant to colonize the murine vaginal tract was significantly decreased. Cellular morphological alterations such as changes in cell shape, chain length, and clumping were also observed in a knockout mutant strain. Given its high expression level in vivo, high degree of conservation among GBS strains, and role in vaginal colonization, BvaP may be an eligible target for GBS vaccination and/or drug therapy. IMPORTANCE Neonatal GBS disease is a major cause of morbidity and mortality, and maternal vaginal colonization is the leading risk factor for the disease. Colonization prevention would greatly impact the rates of disease transmission, but vaccine development has stalled as capsular polysaccharide vaccines have low immunogenicity in vivo. While these vaccines are still in development, the addition of a protein conjugate may prove fruitful in increasing immunogenicity and strain coverage across GBS serotypes. Previous research identified sak_1753 as a highly upregulated gene during murine vaginal colonization. This study reveals that Sak_1753 is required to maintain proper GBS cellular morphology and colonization phenotypes and is required for full in vivo vaginal colonization in a murine model. We have renamed Sak_1753 group B streptococcus vaginal adherence protein (BvaP). The findings of this study indicate that BvaP is important for GBS colonization of the vaginal tract and, given its high expression level in vivo and strain conservation, may be a candidate for vaccine development.
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6
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Lacasse M, Valentin AS, Corvec S, Bémer P, Jolivet-Gougeon A, Plouzeau C, Tandé D, Mereghetti L, Bernard L, Lartigue MF. Genotypic Characterization and Biofilm Production of Group B Streptococcus Strains Isolated from Bone and Joint Infections. Microbiol Spectr 2022; 10:e0232921. [PMID: 35357222 PMCID: PMC9045227 DOI: 10.1128/spectrum.02329-21] [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: 11/24/2021] [Accepted: 02/07/2022] [Indexed: 11/20/2022] Open
Abstract
Bone and joint infections (BJI) represent the second cause of invasive Group B Streptococcus (GBS) infections. Biofilm formation plays a major role in BJI. This study's aim was to analyze the genetic features and biofilm production of GBS strains. In six French laboratories, 77 GBS strains isolated from BJI and 57 strains from vaginal human colonization (Hcol) were characterized and compared by Multi-Locus Sequence Typing (MLST). PCR was used to search for the adhesins (bsaB, lmb, scpB, fbsA, fbsB, hvgA, bibA, bca, srr-1, and srr-2) and Pilus Islands (PI) related genes (PI-1, PI-2a, PI-2b). Biofilm production was studied by crystal violet assay. Strains were categorized into three groups, based on Specific Biofilm Formation (SBF) values defined as: weak, moderate, or strong producers. Molecular study revealed three major clonal complexes (CC) in BJI strains: CC1 (42%), CC23 (22%) and CC10 (14%). Several associations between CC and adhesin/pili were identified: CC1 with srr2, PI-1 + 2a; CC10 with srr-1, bca, PI-1 + 2a; CC17 with fbsB, hvgA, srr-2, PI-1+PI-2b; CC19 with bibA, srr-1, PI-1 + 2a; CC23 with fbsB, bibA, srr-1, PI-2a. The biofilm production was significantly different according to CC, adhesins and pili gene detection. CC10, CC23 and strains harboring fbsB produce more biofilm than CC1, PI-1 + 2a (independently). Finally, SBF values were significantly stronger for Hcol strains rather than for BJI strains (76% versus 40%). This study revealed that Hcol strains appeared to produce stronger biofilm than BJI strains, though they belonged to similar CCs and had the same adhesin and pili content. IMPORTANCE Bone and joint infections (BJI) are pathologies that can be life-threatening and result in compromised functional prognosis for patients. Relapses are common and often related to biofilm formation. Group B streptococci (GBS) BJI increased since the last decade. However, few data are available on this subject in the literature. Our study aims to highlight genotype and biofilm production of GBS isolates from BJI. Seventy-seven GBS strains isolated from BJI and 57 from asymptomatic human vaginal colonization were characterized by multilocus sequence typing (MLST), adhesins content, nature of the pili and the ability to form biofilm. Our results revealed that vaginal human colonization strains produced stronger biofilm than BJI strains, despite belonging to the same phylogenetic lineage and having the same adhesin and pili content.
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Affiliation(s)
| | - Anne-Sophie Valentin
- Université de Tours, INRAE, ISP, Tours, France
- Centre Hospitalier Universitaire de Tours, Service de Bactériologie, Virologie et Hygiène Hospitalière, Tours, France
| | - Stéphane Corvec
- University Hospital Center of Nantes, Bacteriology Department, Nantes University, Nantes, France
| | - Pascale Bémer
- University Hospital Center of Nantes, Bacteriology Department, Nantes University, Nantes, France
| | - Anne Jolivet-Gougeon
- University of Rennes, INSERM, University Hospital of Rennes, NUMECAN Institute (Nutrition Metabolisms and Cancer), Rennes, France
| | - Chloé Plouzeau
- Bacteriology-Hospital Hygiene Department, University Hospital of Poitiers, Poitiers University, Poitiers, France
| | - Didier Tandé
- Bacteriology-Hospital Hygiene Department, University Hospital of Brest, Brest University, Brest, France
| | - Laurent Mereghetti
- Université de Tours, INRAE, ISP, Tours, France
- Centre Hospitalier Universitaire de Tours, Service de Bactériologie, Virologie et Hygiène Hospitalière, Tours, France
| | - Louis Bernard
- Centre Hospitalier Universitaire de Tours, Service de Maladies infectieuses, Tours, France
| | - Marie-Frédérique Lartigue
- Université de Tours, INRAE, ISP, Tours, France
- Centre Hospitalier Universitaire de Tours, Service de Bactériologie, Virologie et Hygiène Hospitalière, Tours, France
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7
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Brokaw A, Furuta A, Dacanay M, Rajagopal L, Adams Waldorf KM. Bacterial and Host Determinants of Group B Streptococcal Vaginal Colonization and Ascending Infection in Pregnancy. Front Cell Infect Microbiol 2021; 11:720789. [PMID: 34540718 PMCID: PMC8446444 DOI: 10.3389/fcimb.2021.720789] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/09/2021] [Indexed: 12/17/2022] Open
Abstract
Group B streptococcus (GBS) is a gram-positive bacteria that asymptomatically colonizes the vaginal tract. However, during pregnancy maternal GBS colonization greatly predisposes the mother and baby to a wide range of adverse outcomes, including preterm birth (PTB), stillbirth, and neonatal infection. Although many mechanisms involved in GBS pathogenesis are partially elucidated, there is currently no approved GBS vaccine. The development of a safe and effective vaccine that can be administered during or prior to pregnancy remains a principal objective in the field, because current antibiotic-based therapeutic strategies do not eliminate all cases of invasive GBS infections. Herein, we review our understanding of GBS disease pathogenesis at the maternal-fetal interface with a focus on the bacterial virulence factors and host defenses that modulate the outcome of infection. We follow GBS along its path from an asymptomatic colonizer of the vagina to an invasive pathogen at the maternal-fetal interface, noting factors critical for vaginal colonization, ascending infection, and vertical transmission to the fetus. Finally, at each stage of infection we emphasize important host-pathogen interactions, which, if targeted therapeutically, may help to reduce the global burden of GBS.
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Affiliation(s)
- Alyssa Brokaw
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Global Health, University of Washington, Seattle, WA, United States
| | - Anna Furuta
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Global Health, University of Washington, Seattle, WA, United States
| | - Matthew Dacanay
- Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, United States
| | - Lakshmi Rajagopal
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Global Health, University of Washington, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States
| | - Kristina M Adams Waldorf
- Department of Global Health, University of Washington, Seattle, WA, United States.,Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, United States.,Department of Obstetrics and Gynecology, University of Washington and Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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8
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van Sorge NM, Bonsor DA, Deng L, Lindahl E, Schmitt V, Lyndin M, Schmidt A, Nilsson OR, Brizuela J, Boero E, Sundberg EJ, van Strijp JAG, Doran KS, Singer BB, Lindahl G, McCarthy AJ. Bacterial protein domains with a novel Ig-like fold target human CEACAM receptors. EMBO J 2021; 40:e106103. [PMID: 33522633 PMCID: PMC8013792 DOI: 10.15252/embj.2020106103] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 01/19/2023] Open
Abstract
Streptococcus agalactiae, also known as group B Streptococcus (GBS), is the major cause of neonatal sepsis in humans. A critical step to infection is adhesion of bacteria to epithelial surfaces. GBS adhesins have been identified to bind extracellular matrix components and cellular receptors. However, several putative adhesins have no host binding partner characterised. We report here that surface‐expressed β protein of GBS binds to human CEACAM1 and CEACAM5 receptors. A crystal structure of the complex showed that an IgSF domain in β represents a novel Ig‐fold subtype called IgI3, in which unique features allow binding to CEACAM1. Bioinformatic assessment revealed that this newly identified IgI3 fold is not exclusively present in GBS but is predicted to be present in adhesins from other clinically important human pathogens. In agreement with this prediction, we found that CEACAM1 binds to an IgI3 domain found in an adhesin from a different streptococcal species. Overall, our results indicate that the IgI3 fold could provide a broadly applied mechanism for bacteria to target CEACAMs.
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Affiliation(s)
- Nina M van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Daniel A Bonsor
- Institute of Human Virology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Liwen Deng
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Verena Schmitt
- Institute of Anatomy, Medical Faculty, University Duisburg-Essen, Essen, Germany
| | - Mykola Lyndin
- Institute of Anatomy, Medical Faculty, University Duisburg-Essen, Essen, Germany.,Department of Pathology, Sumy State University, Sumy, Ukraine
| | - Alexej Schmidt
- Department of Medical Biosciences, Umeå University, Pathology, Umeå, Sweden
| | - Olof R Nilsson
- Department of Laboratory Medicine, Division of Medical Microbiology, Lund University, Lund, Sweden
| | - Jaime Brizuela
- Department of Infectious Disease, MRC Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK
| | - Elena Boero
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Eric J Sundberg
- Institute of Human Virology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD, USA.,Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Kelly S Doran
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Bernhard B Singer
- Institute of Anatomy, Medical Faculty, University Duisburg-Essen, Essen, Germany
| | - Gunnar Lindahl
- Department of Laboratory Medicine, Division of Medical Microbiology, Lund University, Lund, Sweden.,Department of Chemistry, Division of Applied Microbiology, Lund University, Lund, Sweden
| | - Alex J McCarthy
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.,Department of Infectious Disease, MRC Centre for Molecular Bacteriology & Infection, Imperial College London, London, UK
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9
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Deciphering Streptococcal Biofilms. Microorganisms 2020; 8:microorganisms8111835. [PMID: 33233415 PMCID: PMC7700319 DOI: 10.3390/microorganisms8111835] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/10/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.
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10
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Baldan R, Sendi P. Precision Medicine in the Diagnosis and Management of Orthopedic Biofilm Infections. Front Med (Lausanne) 2020; 7:580671. [PMID: 33240905 PMCID: PMC7683765 DOI: 10.3389/fmed.2020.580671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/22/2020] [Indexed: 01/02/2023] Open
Abstract
Orthopedic biofilm infections are difficult to treat and require a multidisciplinary approach to diagnostics and management. Recent advances in the field include methods to disrupt biofilm, sequencing tools, and antibiotic susceptibility tests for bacteria residing in biofilm. The observation of interclonal differences in biofilm properties of the causative microorganisms, together with considerations of comorbidities and polypharmacy in a growing aging population, calls for a personalized approach to treat these infections. In this article, we highlight aspects of precision medicine that may open new perspectives in the diagnosis and management of orthopedic biofilm infections.
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Affiliation(s)
- Rossella Baldan
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Parham Sendi
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Centre for Musculoskeletal Infections, University Hospital Basel, Basel, Switzerland.,Division of Infectious Diseases and Hospital Epidemiology, Departments of Medicine and Clinical Research, University Hospital Basel, Basel, Switzerland.,Department of Orthopaedic and Trauma Surgery, University Hospital Basel, Basel, Switzerland
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11
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Increasing Resistance and Changes in Distribution of Serotypes of Streptococcus agalactiae in Poland. Pathogens 2020; 9:pathogens9070526. [PMID: 32610654 PMCID: PMC7400139 DOI: 10.3390/pathogens9070526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 11/16/2022] Open
Abstract
Streptococcus agalactiae is responsible for serious infections in newborn babies, pregnant women, and other patients. The aim of this study was to evaluate antimicrobial susceptibility, serotype distribution, and virulence determinants of the S. agalactiae isolates derived from clinical specimens considering the global increase of both antibiotic resistance and virulence. A total of 165 isolates were identified and serotyped by PCR techniques. Antimicrobial susceptibility was assessed by disk diffusion method, gradient diffusion method and VITEK® System. Virulence associated genes were investigated by PCR; ability to form biofilm was assessed using a microtiter plate assay. The highest observed MIC value for penicillin G was 0.12 µg/mL, seen in 8.5% of isolates. Resistance to erythromycin and clindamycin were found in 30.38% and 24.8% of the strains, respectively. The serotype III (32.73%), V (25.45%), and Ia (18.18%) were found as the most frequently represented. Previously unidentified strains in Poland, belonging to serotypes VI (three strains) and VII (one strain) were recognized. The presence of genes encoding various virulence factors as well as diverse ability to form biofilm were found. In conclusion, macrolide-resistance and decreased susceptibility to penicillin G were revealed signifying the increasing resistance among group B streptococci. Moreover, the presence of genes encoding various virulence factors and the ability to form biofilm were confirmed indicating their role in the pathomechanisms of the evaluated GBS infections.
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12
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Two-Component Signal Transduction Systems in the Human Pathogen Streptococcus agalactiae. Infect Immun 2020; 88:IAI.00931-19. [PMID: 31988177 DOI: 10.1128/iai.00931-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Streptococcus agalactiae (group B Streptococcus [GBS]) is an important cause of invasive infection in newborns, maternal women, and older individuals with underlying chronic illnesses. GBS has many mechanisms to adapt and survive in its host, and these mechanisms are often controlled via two-component signal transduction systems. In GBS, more than 20 distinct two-component systems (TCSs) have been classified to date, consisting of canonical TCSs as well as orphan and atypical sensors and regulators. These signal transducing systems are necessary for metabolic regulation, resistance to antibiotics and antimicrobials, pathogenesis, and adhesion to the mucosal surfaces to colonize the host. This minireview discusses the structures of these TCSs in GBS as well as how selected systems regulate essential cellular processes such as survival and colonization. GBS contains almost double the number of TCSs compared to the closely related Streptococcus pyogenes and Streptococcus pneumoniae, and while research on GBS TCSs has been increasing in recent years, no comprehensive reviews of these TCSs exist, making this review especially relevant.
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13
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Fibronectin and laminin induce biofilm formation by Streptococcus uberis and decrease its penicillin susceptibility. Microb Pathog 2019; 136:103652. [DOI: 10.1016/j.micpath.2019.103652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/18/2019] [Accepted: 08/05/2019] [Indexed: 01/02/2023]
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14
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Armistead B, Oler E, Adams Waldorf K, Rajagopal L. The Double Life of Group B Streptococcus: Asymptomatic Colonizer and Potent Pathogen. J Mol Biol 2019; 431:2914-2931. [PMID: 30711542 DOI: 10.1016/j.jmb.2019.01.035] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 12/22/2022]
Abstract
Group B streptococcus (GBS) is a β-hemolytic gram-positive bacterium that colonizes the lower genital tract of approximately 18% of women globally as an asymptomatic member of the gastrointestinal and/or vaginal flora. If established in other host niches, however, GBS is highly pathogenic. During pregnancy, ascending GBS infection from the vagina to the intrauterine space is associated with preterm birth, stillbirth, and fetal injury. In addition, vertical transmission of GBS during or after birth results in life-threatening neonatal infections, including pneumonia, sepsis, and meningitis. Although the mechanisms by which GBS traffics from the lower genital tract to vulnerable host niches are not well understood, recent advances have revealed that many of the same bacterial factors that promote asymptomatic vaginal carriage also facilitate dissemination and virulence. Furthermore, highly pathogenic GBS strains have acquired unique factors that enhance survival in invasive niches. Several host factors also exist that either subdue GBS upon vaginal colonization or alternatively permit invasive infection. This review summarizes the GBS and host factors involved in GBS's state as both an asymptomatic colonizer and an invasive pathogen. Gaining a better understanding of these mechanisms is key to overcoming the challenges associated with vaccine development and identification of novel strategies to mitigate GBS virulence.
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Affiliation(s)
- Blair Armistead
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle 98101, WA, USA
| | - Elizabeth Oler
- Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle 98195, WA, USA
| | - Kristina Adams Waldorf
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle 98195, WA, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle 98109, WA, USA; Sahlgrenska Academy, Gothenburg University, Gothenburg 413 90, Sweden
| | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle 98101, WA, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle 98195, WA, USA.
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15
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Nie S, Lu X, Hu YW, Zheng L, Wang Q. Influence of environmental and genotypic factors on biofilm formation by clinical isolates of group B streptococci. Microb Pathog 2018; 121:45-50. [DOI: 10.1016/j.micpath.2018.05.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 04/16/2018] [Accepted: 05/11/2018] [Indexed: 12/13/2022]
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16
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Pietrocola G, Arciola CR, Rindi S, Montanaro L, Speziale P. Streptococcus agalactiae Non-Pilus, Cell Wall-Anchored Proteins: Involvement in Colonization and Pathogenesis and Potential as Vaccine Candidates. Front Immunol 2018; 9:602. [PMID: 29686667 PMCID: PMC5900788 DOI: 10.3389/fimmu.2018.00602] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/09/2018] [Indexed: 11/13/2022] Open
Abstract
Group B Streptococcus (GBS) remains an important etiological agent of several infectious diseases including neonatal septicemia, pneumonia, meningitis, and orthopedic device infections. This pathogenicity is due to a variety of virulence factors expressed by Streptococcus agalactiae. Single virulence factors are not sufficient to provoke a streptococcal infection, which is instead promoted by the coordinated activity of several pathogenicity factors. Such determinants, mostly cell wall-associated and secreted proteins, include adhesins that mediate binding of the pathogen to host extracellular matrix/plasma ligands and cell surfaces, proteins that cooperate in the invasion of and survival within host cells and factors that neutralize phagocytosis and/or modulate the immune response. The genome-based approaches and bioinformatics tools and the extensive use of biophysical and biochemical methods and animal model studies have provided a great wealth of information on the molecular structure and function of these virulence factors. In fact, a number of new GBS surface-exposed or secreted proteins have been identified (GBS immunogenic bacterial adhesion protein, leucine-rich repeat of GBS, serine-rich repeat proteins), the three-dimensional structures of known streptococcal proteins (αC protein, C5a peptidase) have been solved and an understanding of the pathogenetic role of "old" and new determinants has been better defined in recent years. Herein, we provide an update of our current understanding of the major surface cell wall-anchored proteins from GBS, with emphasis on their biochemical and structural properties and the pathogenetic roles they may have in the onset and progression of host infection. We also focus on the antigenic profile of these compounds and discuss them as targets for therapeutic intervention.
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Affiliation(s)
- Giampiero Pietrocola
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Carla Renata Arciola
- Research Unit on Implant Infections, Rizzoli Orthopaedic Institute, Bologna, Italy.,Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Simonetta Rindi
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Lucio Montanaro
- Research Unit on Implant Infections, Rizzoli Orthopaedic Institute, Bologna, Italy.,Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Pietro Speziale
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Department of Industrial and Information Engineering, University of Pavia, Pavia, Italy
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17
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Shabayek S, Spellerberg B. Group B Streptococcal Colonization, Molecular Characteristics, and Epidemiology. Front Microbiol 2018; 9:437. [PMID: 29593684 PMCID: PMC5861770 DOI: 10.3389/fmicb.2018.00437] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 02/26/2018] [Indexed: 11/13/2022] Open
Abstract
Streptococcus agalactiae or group B streptococcus (GBS) is a leading cause of serious neonatal infections. GBS is an opportunistic commensal constituting a part of the intestinal and vaginal physiologic flora and maternal colonization is the principal route of GBS transmission. GBS is a pathobiont that converts from the asymptomatic mucosal carriage state to a major bacterial pathogen causing severe invasive infections. At present, as many as 10 serotypes (Ia, Ib, and II–IX) are recognized. The aim of the current review is to shed new light on the latest epidemiological data and clonal distribution of GBS in addition to discussing the most important colonization determinants at a molecular level. The distribution and predominance of certain serotypes is susceptible to variations and can change over time. With the availability of multilocus sequence typing scheme (MLST) data, it became clear that GBS strains of certain clonal complexes possess a higher potential to cause invasive disease, while other harbor mainly colonizing strains. Colonization and persistence in different host niches is dependent on the adherence capacity of GBS to host cells and tissues. Bacterial biofilms represent well-known virulence factors with a vital role in persistence and chronic infections. In addition, GBS colonization, persistence, translocation, and invasion of host barriers are largely dependent on their adherence abilities to host cells and extracellular matrix proteins (ECM). Major adhesins mediating GBS interaction with host cells include the fibrinogen-binding proteins (Fbs), the laminin-binding protein (Lmb), the group B streptococcal C5a peptidase (ScpB), the streptococcal fibronectin binding protein A (SfbA), the GBS immunogenic bacterial adhesin (BibA), and the hypervirulent adhesin (HvgA). These adhesins facilitate persistent and intimate contacts between the bacterial cell and the host, while global virulence regulators play a major role in the transition to invasive infections. This review combines for first time epidemiological data with data on adherence and colonization for GBS. Investigating the epidemiology along with understanding the determinants of mucosal colonization and the development of invasive disease at a molecular level is therefore important for the development of strategies to prevent invasive GBS disease worldwide.
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Affiliation(s)
- Sarah Shabayek
- Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
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18
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Patras KA, Nizet V. Group B Streptococcal Maternal Colonization and Neonatal Disease: Molecular Mechanisms and Preventative Approaches. Front Pediatr 2018; 6:27. [PMID: 29520354 PMCID: PMC5827363 DOI: 10.3389/fped.2018.00027] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Group B Streptococcus (GBS) colonizes the gastrointestinal and vaginal epithelium of a significant percentage of healthy women, with potential for ascending intrauterine infection or transmission during parturition, creating a risk of serious disease in the vulnerable newborn. This review highlights new insights on the bacterial virulence determinants, host immune responses, and microbiome interactions that underpin GBS vaginal colonization, the proximal step in newborn infectious disease pathogenesis. From the pathogen perspective, the function GBS adhesins and biofilms, β-hemolysin/cytolysin toxin, immune resistance factors, sialic acid mimicry, and two-component transcriptional regulatory systems are reviewed. From the host standpoint, pathogen recognition, cytokine responses, and the vaginal mucosal and placental immunity to the pathogen are detailed. Finally, the rationale, efficacy, and potential unintended consequences of current universal recommended intrapartum antibiotic prophylaxis are considered, with updates on new developments toward a GBS vaccine or alternative approaches to reducing vaginal colonization.
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Affiliation(s)
- Kathryn A Patras
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
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19
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Gendrin C, Shubin NJ, Boldenow E, Merillat S, Clauson M, Power D, Doran KS, Abrink M, Pejler G, Rajagopal L, Piliponsky AM. Mast cell chymase decreases the severity of group B Streptococcus infections. J Allergy Clin Immunol 2017; 142:120-129.e6. [PMID: 28916188 DOI: 10.1016/j.jaci.2017.07.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 07/06/2017] [Accepted: 07/24/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Group B Streptococcus (GBS) or Streptococcus agalactiae are β-hemolytic gram-positive bacteria that colonize the lower genital tracts of women and are frequently associated with infections during pregnancy. Innate immune defenses are critical for controlling GBS dissemination and systemic infection. Mast cells are resident sentinel cells that come into contact with pathogens early during colonization and infection. OBJECTIVE We aimed to investigate the contribution of chymase to systemic GBS infection and rates of preterm birth. METHODS Pharmacologic and genetic approaches using mice deficient in mast cell protease (MCPT) 4, the mouse functional homologue of human chymase, were used. RESULTS Our studies show that mast cells release a protease with chymotrypsin-like cleavage specificity in response to GBS. Additionally, increased GBS systemic infection and preterm births were observed in MCPT4-deficient mice versus MCPT4-sufficient mice. Furthermore, we observed that proteolytic cleavage of the host extracellular matrix protein fibronectin by peritoneal cell-derived mast cell lysates diminished GBS adherence. Consistent with this observation, the increase in GBS dissemination and preterm births observed in MCPT4-deficient mice was abolished when GBS was deficient in expression of the fibronectin-binding protein SfbA. CONCLUSIONS Taken together, our results suggest that the protective effect of MCPT4 against GBS dissemination and preterm labor can be attributed in part to MCPT4-mediated proteolysis of fibronectin. Our studies reveal a novel role of mast cells in defense against bacterial infections.
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Affiliation(s)
- Claire Gendrin
- Department of Pediatric Infectious Diseases, University of Washington, Seattle, Wash; Seattle Children's Research Institute, Seattle, Wash
| | | | | | - Sean Merillat
- Seattle Children's Research Institute, Seattle, Wash
| | | | - Danial Power
- Seattle Children's Research Institute, Seattle, Wash
| | - Kelly S Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, Calif; Department of Pediatrics, University of California San Diego School of Medicine, La Jolla, Calif
| | - Magnus Abrink
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University for Agricultural Sciences, Uppsala, Sweden
| | - Gunnar Pejler
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden; Department of Anatomy, Physiology and Biochemistry, the Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases, University of Washington, Seattle, Wash; Seattle Children's Research Institute, Seattle, Wash; Department of Global Health, University of Washington, Seattle, Wash.
| | - Adrian M Piliponsky
- Department of Pediatric Infectious Diseases, University of Washington, Seattle, Wash; Seattle Children's Research Institute, Seattle, Wash.
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20
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Vornhagen J, Adams Waldorf KM, Rajagopal L. Perinatal Group B Streptococcal Infections: Virulence Factors, Immunity, and Prevention Strategies. Trends Microbiol 2017. [PMID: 28633864 DOI: 10.1016/j.tim.2017.05.013] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Group B streptococcus (GBS) or Streptococcus agalactiae is a β-hemolytic, Gram-positive bacterium that is a leading cause of neonatal infections. GBS commonly colonizes the lower gastrointestinal and genital tracts and, during pregnancy, neonates are at risk of infection. Although intrapartum antibiotic prophylaxis during labor and delivery has decreased the incidence of early-onset neonatal infection, these measures do not prevent ascending infection that can occur earlier in pregnancy leading to preterm births, stillbirths, or late-onset neonatal infections. Prevention of GBS infection in pregnancy is complex and is likely influenced by multiple factors, including pathogenicity, host factors, vaginal microbiome, false-negative screening, and/or changes in antibiotic resistance. A deeper understanding of the mechanisms of GBS infections during pregnancy will facilitate the development of novel therapeutics and vaccines. Here, we summarize and discuss important advancements in our understanding of GBS vaginal colonization, ascending infection, and preterm birth.
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Affiliation(s)
- Jay Vornhagen
- Department of Global Health, University of Washington, Seattle, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Kristina M Adams Waldorf
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, USA; Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden
| | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA.
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21
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Efstratiou A, Lamagni T, Turner CE. Streptococci and Enterococci. Infect Dis (Lond) 2017. [DOI: 10.1016/b978-0-7020-6285-8.00177-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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22
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Wang Y, Wei Y, Yuan S, Tao H, Dong J, Zhang Z, Tian W, Liu C. Bacillus anthracis S-layer protein BslA binds to extracellular matrix by interacting with laminin. BMC Microbiol 2016; 16:183. [PMID: 27514510 PMCID: PMC4981971 DOI: 10.1186/s12866-016-0802-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 08/04/2016] [Indexed: 01/27/2023] Open
Abstract
Background The Bacillus anthracis S-layer protein, BslA, plays a crucial role in mammalian infection. BslA is required to mediate adherence between host cells and vegetative forms of bacteria and this interaction promotes target organs adherence and blood–brain barrier (BBB) penetration in vivo. This study attempts to identify the potential eukaryotic ligand(s) for B. anthracis BslA protein. Results Biochemical approaches have indicated that the putative host cell ligand(s) for BslA is a surface protein, which is independent of the sugar components for binding to Bs1A. A ligand screening using blot overlays, far Western blots and mass spectrometry analyses revealed that BslA binds to mammalian laminin. ELISA based solid-phase binding assays and surface plasmon resonance assays demonstrated that there were high affinity interactions between BslA(260–652) and laminin. The SPR results also revealed the dissociation constants values of 3.172 × 10−9M for the binding of BslA(260–652) to laminin. Conclusions These data demonstrated that laminin is a ligand for BslA. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0802-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yanchun Wang
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China.
| | - Ying Wei
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China.,School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Shengling Yuan
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China
| | - Haoxia Tao
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China
| | - Jie Dong
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China
| | - Zhaoshan Zhang
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China
| | - Wei Tian
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Chunjie Liu
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China.
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23
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Buscetta M, Firon A, Pietrocola G, Biondo C, Mancuso G, Midiri A, Romeo L, Galbo R, Venza M, Venza I, Kaminski PA, Gominet M, Teti G, Speziale P, Trieu-Cuot P, Beninati C. PbsP, a cell wall-anchored protein that binds plasminogen to promote hematogenous dissemination of group B Streptococcus. Mol Microbiol 2016; 101:27-41. [PMID: 26888569 DOI: 10.1111/mmi.13357] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2016] [Indexed: 02/04/2023]
Abstract
Streptococcus agalactiae (Group B Streptococcus or GBS) is a leading cause of invasive infections in neonates whose virulence is dependent on its ability to interact with cells and host components. We here characterized a surface protein with a critical function in GBS pathophysiology. This adhesin, designated PbsP, possesses two Streptococcal Surface Repeat domains, a methionine and lysine-rich region, and a LPXTG cell wall-anchoring motif. PbsP mediates plasminogen (Plg) binding both in vitro and in vivo and we showed that cell surface-bound Plg can be activated into plasmin by tissue plasminogen activator to increase the bacterial extracellular proteolytic activity. Absence of PbsP results in a decreased bacterial transmigration across brain endothelial cells and impaired virulence in a murine model of infection. PbsP is conserved among the main GBS lineages and is a major plasminogen adhesin in non-CC17 GBS strains. Importantly, immunization of mice with recombinant PbsP confers protective immunity. Our results indicate that GBS have evolved different strategies to recruit Plg which indicates that the ability to acquire cell surface proteolytic activity is essential for the invasiveness of this bacterium.
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Affiliation(s)
- Marco Buscetta
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy.,Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Arnaud Firon
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Giampiero Pietrocola
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Carmelo Biondo
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Giuseppe Mancuso
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Angelina Midiri
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Letizia Romeo
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Roberta Galbo
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Mario Venza
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Isabella Venza
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Pierre-Alexandre Kaminski
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Myriam Gominet
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Giuseppe Teti
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Concetta Beninati
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy.,Scylla Biotech Srl, Messina, Italy
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24
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Dong J, Wei Y, Ye X, Sun C, Tian Y, Lu M, Du J, Chen Z. Discovery and expression of 3 siglecs-like in Oreochromis niloticus neutrophil, and their interaction with group B streptococcal sialylated capsular polysaccharides. Mol Immunol 2016; 73:158-69. [DOI: 10.1016/j.molimm.2016.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 11/30/2022]
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25
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Buscetta M, Papasergi S, Firon A, Pietrocola G, Biondo C, Mancuso G, Midiri A, Romeo L, Teti G, Speziale P, Trieu-Cuot P, Beninati C. FbsC, a novel fibrinogen-binding protein, promotes Streptococcus agalactiae-host cell interactions. J Biol Chem 2015; 289:21003-21015. [PMID: 24904056 DOI: 10.1074/jbc.m114.553073] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Streptococcus agalactiae (group B Streptococcus or GBS) is a common cause of invasive infections in newborn infants and adults. The ability of GBS to bind human fibrinogen is of crucial importance in promoting colonization and invasion of host barriers. We characterized here a novel fibrinogen-binding protein of GBS, designated FbsC (Gbs0791), which is encoded by the prototype GBS strain NEM316. FbsC, which bears two bacterial immunoglobulin-like tandem repeat domains and a C-terminal cell wall-anchoring motif (LPXTG), was found to be covalently linked to the cell wall by the housekeeping sortase A. Studies using recombinant FbsC indicated that it binds fibrinogen in a dose-dependent and saturable manner, and with moderate affinity. Expression of FbsC was detected in all clinical GBS isolates, except those belonging to the hypervirulent lineage ST17. Deletion of fbsC decreases NEM316 abilities to adhere to and invade human epithelial and endothelial cells, and to form biofilm in vitro. Notably, bacterial adhesion to fibrinogen and fibrinogen binding to bacterial cells were abolished following fbsC deletion in NEM316. Moreover, the virulence of the fbsC deletion mutant and its ability to colonize the brain were impaired in murine models of infection. Finally, immunization with recombinant FbsC significantly protected mice from lethal GBS challenge. In conclusion, FbsC is a novel fibrinogen-binding protein expressed by most GBS isolates that functions as a virulence factor by promoting invasion of epithelial and endothelial barriers. In addition, the protein has significant immunoprotective activity and may be a useful component of an anti-GBS vaccine.
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26
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Rosini R, Margarit I. Biofilm formation by Streptococcus agalactiae: influence of environmental conditions and implicated virulence factors. Front Cell Infect Microbiol 2015; 5:6. [PMID: 25699242 PMCID: PMC4316791 DOI: 10.3389/fcimb.2015.00006] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/14/2015] [Indexed: 12/12/2022] Open
Abstract
Streptococcus agalactiae (Group B Streptococcus, GBS) is an important human pathogen that colonizes the urogenital and/or the lower gastro-intestinal tract of up to 40% of healthy women of reproductive age and is a leading cause of sepsis and meningitis in the neonates. GBS can also infect the elderly and immuno-compromised adults, and is responsible for mastitis in bovines. Like other Gram-positive bacteria, GBS can form biofilm-like three-dimensional structures that could enhance its ability to colonize and persist in the host. Biofilm formation by GBS has been investigated in vitro and appears tightly controlled by environmental conditions. Several adhesins have been shown to play a role in the formation of GBS biofilm-like structures, among which are the protein components of pili protruding outside the bacterial surface. Remarkably, antibodies directed against pilus proteins can prevent the formation of biofilms. The implications of biofilm formation in the context of GBS asymptomatic colonization and dissemination to cause invasive disease remain to be investigated in detail.
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Landwehr-Kenzel S, Henneke P. Interaction of Streptococcus agalactiae and Cellular Innate Immunity in Colonization and Disease. Front Immunol 2014; 5:519. [PMID: 25400631 PMCID: PMC4212683 DOI: 10.3389/fimmu.2014.00519] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/05/2014] [Indexed: 12/18/2022] Open
Abstract
Streptococcus agalactiae (Group B streptococcus, GBS) is highly adapted to humans, where it is a normal constituent of the intestinal and vaginal flora. Yet, GBS has highly invasive potential and causes excessive inflammation, sepsis, and death at the beginning of life, in the elderly and in diabetic patients. Thus, GBS is a model pathobiont that thrives in the healthy host, but has not lost its potential virulence during coevolution with mankind. It remains incompletely understood how the innate immune system contains GBS in the natural niches, the intestinal and genital tracts, and which molecular events underlie breakdown of mucocutaneous resistance. Newborn infants between days 7 and 90 of life are at risk of a particularly striking sepsis manifestation (late-onset disease), where the transition from colonization to invasion and dissemination, and thus from health to severe sepsis is typically fulminant and not predictable. The great majority of late-onset sepsis cases are caused by one clone, GBS ST17, which expresses HvgA as a signature virulence factor and adhesin. In mice, HvgA promotes the crossing of both the mucosal and the blood–brain barrier. Expression levels of HvgA and other GBS virulence factors, such as pili and toxins, are regulated by the upstream two-component control system CovR/S. This in turn is modulated by acidic epithelial pH, high glucose levels, and during the passage through the mouse intestine. After invasion, GBS has the ability to subvert innate immunity by mechanisms like glycerinaldehyde-3-phosphate-dehydrogenase-dependent induction of IL-10 and β-protein binding to the inhibitory phagocyte receptors sialic acid binding immunoglobulin-like lectin 5 and 14. On the host side, sensing of GBS nucleic acids and lipopeptides by both Toll-like receptors and the inflammasome appears to be critical for host resistance against GBS. Yet, comprehensive models on the interplay between GBS and human immune cells at the colonizing site are just emerging.
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Affiliation(s)
- Sybille Landwehr-Kenzel
- Berlin-Brandenburg Center for Regenerative Therapies, Charité University Medicine Berlin , Berlin , Germany ; Berlin-Brandenburg School for Regenerative Therapies, Charité University Medicine Berlin , Berlin , Germany ; Department of Pediatric Pulmonology and Immunology, Charité University Medicine Berlin , Berlin , Germany
| | - Philipp Henneke
- Center for Pediatrics and Adolescent Medicine, University Medical Center Freiburg , Freiburg , Germany ; Center for Chronic Immunodeficiency, University Medical Center Freiburg , Freiburg , Germany
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Randis TM, Gelber SE, Hooven TA, Abellar RG, Akabas LH, Lewis EL, Walker LB, Byland LM, Nizet V, Ratner AJ. Group B Streptococcus β-hemolysin/cytolysin breaches maternal-fetal barriers to cause preterm birth and intrauterine fetal demise in vivo. J Infect Dis 2014; 210:265-73. [PMID: 24474814 DOI: 10.1093/infdis/jiu067] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Maternal vaginal colonization with Streptococcus agalactiae (Group B Streptococcus [GBS]) is a precursor to chorioamnionitis, fetal infection, and neonatal sepsis, but the understanding of specific factors in the pathogenesis of ascending infection remains limited. METHODS We used a new murine model to evaluate the contribution of the pore-forming GBS β-hemolysin/cytolysin (βH/C) to vaginal colonization, ascension, and fetal infection. RESULTS Competition assays demonstrated a marked advantage to βH/C-expressing GBS during colonization. Intrauterine fetal demise and/or preterm birth were observed in 54% of pregnant mice colonized with wild-type (WT) GBS and 0% of those colonized with the toxin-deficient cylE knockout strain, despite efficient colonization and ascension by both strains. Robust placental inflammation, disruption of maternal-fetal barriers, and fetal infection were more frequent in animals colonized with WT bacteria. Histopathologic examination revealed bacterial tropism for fetal lung and liver. CONCLUSIONS Preterm birth and fetal demise are likely the direct result of toxin-induced damage and inflammation rather than differences in efficiency of ascension into the upper genital tract. These data demonstrate a distinct contribution of βH/C to GBS chorioamnionitis and subsequent fetal infection in vivo and showcase a model for this most proximal step in GBS pathogenesis.
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Affiliation(s)
- Tara M Randis
- Department of Pediatrics, Columbia University, New York, New York
| | - Shari E Gelber
- Department of Obstetrics and Gynecology, Weill-Cornell Medical Center, New York, New York
| | - Thomas A Hooven
- Department of Pediatrics, Columbia University, New York, New York
| | - Rosanna G Abellar
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Leor H Akabas
- Department of Pediatrics, Columbia University, New York, New York
| | - Emma L Lewis
- Department of Pediatrics, Columbia University, New York, New York
| | - Lindsay B Walker
- Department of Pediatrics, Columbia University, New York, New York
| | - Leah M Byland
- Department of Pediatrics, Columbia University, New York, New York
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California
| | - Adam J Ratner
- Department of Pediatrics, Columbia University, New York, New York
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