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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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2
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Ma J, Wu H, Ma Z, Wu Z. Bacterial and host factors involved in zoonotic Streptococcal meningitis. Microbes Infect 2024:105335. [PMID: 38582147 DOI: 10.1016/j.micinf.2024.105335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/08/2024]
Abstract
Zoonotic streptococci cause several invasive diseases with high mortality rates, especially meningitis. Numerous studies elucidated the meningitis pathogenesis of zoonotic streptococci, some specific to certain bacterial species. In contrast, others are shared among different bacterial species, involving colonization and invasion of mucosal barriers, survival in the bloodstream, breaching the blood-brain and/or blood-cerebrospinal fluid barrier to access the central nervous system, and triggering inflammation of the meninges. This review focuses on the recent advancements in comprehending the molecular and cellular events of five major zoonotic streptococci responsible for causing meningitis in humans or animals, including Streptococcus agalactiae, Streptococcus equi subspecies zooepidemicus, Streptococcus suis, Streptococcus dysgalactiae, and Streptococcus iniae. The underlying mechanism was summarized into four themes, including 1) bacterial survival in blood, 2) brain microvascular endothelial cell adhesion and invasion, 3) penetration of the blood-brain barrier, and 4) activation of the immune system and inflammatory reaction within the brain. This review may contribute to developing therapeutics to prevent or mitigate injury of streptococcal meningitis and improve risk stratification.
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Affiliation(s)
- Jiale Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210014, China; WOAH Reference Lab for Swine Streptococcosis, Nanjing 210014, China
| | - Huizhen Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210014, China; WOAH Reference Lab for Swine Streptococcosis, Nanjing 210014, China
| | - Zhe Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210014, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
| | - Zongfu Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210014, China; WOAH Reference Lab for Swine Streptococcosis, Nanjing 210014, China; Guangdong Provincial Key Laboratory of Research on the Technology of Pig-breeding and Pig-disease Prevention, Guangzhou 511400, China.
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3
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Dhar N, Mohamed E, Kirstein F, Williams M, Dorasamy S, van Zyl P, Robertson MJ, Anderson T, Harden LM, Jardine K, Veeraraghavan B, Wilson S, Tippoo P, Madhi SA, Kwatra G. Immune responses against group B Streptococcus monovalent and pentavalent capsular polysaccharide tetanus toxoid conjugate vaccines in Balb/c mice. iScience 2023; 26:107380. [PMID: 37575182 PMCID: PMC10415928 DOI: 10.1016/j.isci.2023.107380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/31/2023] [Accepted: 07/07/2023] [Indexed: 08/15/2023] Open
Abstract
Immunization of pregnant women with Group B Streptococcus (GBS) capsular polysaccharide (CPS) conjugate vaccine (CV) could protect young infants against invasive GBS disease. We evaluated the immunogenicity of investigational five GBS monovalent (serotypes Ia, Ib, II, III, and V) CPS-tetanus toxoid (TT)-CV with adjuvant and GBS pentavalent CPS-TT-CV with adjuvant (GBS5-CV-adj) and without adjuvant (GBS5-CV-no-adj), in Balb/c mice. Aluminum phosphate was the adjuvant in the formulations, where included. The homotypic immunoglobulin G (IgG) geometric mean concentration (GMC) and opsonophagocytic activity (OPA) geometric mean titer (GMT) did not differ after the third dose of the GBS5-CV-adj vaccine compared with the monovalent counterparts for all five serotypes. The GBS5-CV-adj induced higher post-vaccination serotype-specific IgG GMCs and OPA GMTs compared to GBS5-CV-no_adj. The GBS5-CV with and without adjuvant should be considered for further development as a potential vaccine for pregnant women to protect their infants against invasive GBS disease.
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Affiliation(s)
- Nisha Dhar
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | | | | | | | | | | | | | - Lois M. Harden
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Kimberly Jardine
- Wits Research Animal Facility, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | | | | | - Shabir A. Madhi
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- African Leadership in Vaccinology Expertise, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gaurav Kwatra
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
- African Leadership in Vaccinology Expertise, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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4
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Bee GCW, Lokken-Toyli KL, Yeung ST, Rodriguez L, Zangari T, Anderson EE, Ghosh S, Rothlin CV, Brodin P, Khanna KM, Weiser JN. Age-dependent differences in efferocytosis determine the outcome of opsonophagocytic protection from invasive pathogens. Immunity 2023; 56:1255-1268.e5. [PMID: 37059107 PMCID: PMC10330046 DOI: 10.1016/j.immuni.2023.03.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/22/2022] [Accepted: 03/21/2023] [Indexed: 04/16/2023]
Abstract
In early life, susceptibility to invasive infection skews toward a small subset of microbes, whereas other pathogens associated with diseases later in life, including Streptococcus pneumoniae (Spn), are uncommon among neonates. To delineate mechanisms behind age-dependent susceptibility, we compared age-specific mouse models of invasive Spn infection. We show enhanced CD11b-dependent opsonophagocytosis by neonatal neutrophils improved protection against Spn during early life. The augmented function of neonatal neutrophils was mediated by higher CD11b surface expression at the population level due to dampened efferocytosis, which also resulted in more CD11bhi "aged" neutrophils in peripheral blood. Dampened efferocytosis during early life could be attributed to the lack of CD169+ macrophages in neonates and reduced systemic expressions of multiple efferocytic mediators, including MerTK. On experimentally impairing efferocytosis later in life, CD11bhi neutrophils increased and protection against Spn improved. Our findings reveal how age-dependent differences in efferocytosis determine infection outcome through the modulation of CD11b-driven opsonophagocytosis and immunity.
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Affiliation(s)
- Gavyn Chern Wei Bee
- Department of Microbiology, New York University Grossman School of Medicine, New York, USA.
| | - Kristen L Lokken-Toyli
- Department of Microbiology, New York University Grossman School of Medicine, New York, USA
| | - Stephen T Yeung
- Department of Microbiology, New York University Grossman School of Medicine, New York, USA
| | - Lucie Rodriguez
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Tonia Zangari
- Department of Microbiology, New York University Grossman School of Medicine, New York, USA
| | - Exene E Anderson
- Department of Microbiology, New York University Grossman School of Medicine, New York, USA
| | - Sourav Ghosh
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA; Department of Neurology, Yale School of Medicine, New Haven, CT, USA
| | - Carla V Rothlin
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA; Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Petter Brodin
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden; Department of Immunology & Inflammation, Imperial College London, London, UK
| | - Kamal M Khanna
- Department of Microbiology, New York University Grossman School of Medicine, New York, USA; Laura & Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
| | - Jeffrey N Weiser
- Department of Microbiology, New York University Grossman School of Medicine, New York, USA.
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5
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Janžič L, Repas J, Pavlin M, Zemljić-Jokhadar Š, Ihan A, Kopitar AN. Macrophage polarization during Streptococcus agalactiae infection is isolate specific. Front Microbiol 2023; 14:1186087. [PMID: 37213504 PMCID: PMC10192866 DOI: 10.3389/fmicb.2023.1186087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/17/2023] [Indexed: 05/23/2023] Open
Abstract
Introduction Streptococcus agalactiae (Group B Streptococcus, GBS), a Gram-positive commensal in healthy adults, remains a major cause of neonatal infections, usually manifesting as sepsis, meningitis, or pneumonia. Intrapartum antibiotic prophylaxis has greatly reduced the incidence of early-onset disease. However, given the lack of effective measures to prevent the risk of late-onset disease and invasive infections in immunocompromised individuals, more studies investigating the GBS-associated pathogenesis and the interplay between bacteria and host immune system are needed. Methods Here, we examined the impact of 12 previously genotyped GBS isolates belonging to different serotypes and sequence types on the immune response of THP-1 macrophages. Results Flow cytometry analysis showed isolate-specific differences in phagocytic uptake, ranging from 10% for isolates of serotype Ib, which possess the virulence factor protein β, to over 70% for isolates of serotype III. Different isolates also induced differential expression of co-stimulatory molecules and scavenger receptors with colonizing isolates inducing higher expression levels of CD80 and CD86 compared to invasive isolates. In addition, real-time measurements of metabolism revealed that macrophages enhanced both glycolysis and mitochondrial respiration after GBS infection, with isolates of serotype III being the most potent activators of glycolysis and glycolytic ATP production. Macrophages also showed differential resistance to GBS-mediated cell cytotoxicity as measured by LDH release and real-time microscopy. The differences were evident both between serotypes and between isolates obtained from different specimens (colonizing or invasive isolates) demonstrating the higher cytotoxicity of vaginal compared with blood isolates. Conclusions Thus, the data suggest that GBS isolates differ in their potential to become invasive or remain colonizing. In addition, colonizing isolates appear to be more cytotoxic, whereas invasive isolates appear to exploit macrophages to their advantage, avoiding the immune recognition and antibiotics.
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Affiliation(s)
- Larisa Janžič
- Department of Cell Immunology, Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jernej Repas
- Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Mojca Pavlin
- Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Group for Nano and Biotechnological Applications, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Špela Zemljić-Jokhadar
- Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Alojz Ihan
- Department of Cell Immunology, Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Andreja Nataša Kopitar
- Department of Cell Immunology, Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- *Correspondence: Andreja Nataša Kopitar,
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6
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Group B Streptococcus: Virulence Factors and Pathogenic Mechanism. Microorganisms 2022; 10:microorganisms10122483. [PMID: 36557736 PMCID: PMC9784991 DOI: 10.3390/microorganisms10122483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/10/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Group B Streptococcus (GBS) or Streptococcus agalactiae is a major cause of neonatal mortality. When colonizing the lower genital tract of pregnant women, GBS may cause premature birth and stillbirth. If transmitted to the newborn, it may result in life-threatening illnesses, including sepsis, meningitis, and pneumonia. Moreover, through continuous evolution, GBS can use its original structure and unique factors to greatly improve its survival rate in the human body. This review discusses the key virulence factors that facilitate GBS invasion and colonization and their action mechanisms. A comprehensive understanding of the role of virulence factors in GBS infection is crucial to develop better treatment options and screen potential candidate molecules for the development of the vaccine.
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7
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Hao J, Wang S, Wei Z, Zhang Q, Wu Z, Lin Y, Yang J, Zhang J, Zhang D, Li A. Construction of Streptococcus agalactiae sialic acid mutant and evaluation of its potential as a live attenuated vaccine in Nile tilapia (Oreochromis niloticus). J Appl Microbiol 2022; 133:2403-2416. [PMID: 35801502 DOI: 10.1111/jam.15706] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 06/07/2022] [Accepted: 07/04/2022] [Indexed: 11/28/2022]
Abstract
AIMS This study aimed to develop a live attenuated vaccine as an effective approach to prevent streptococcosis in tilapia (Oreochromis niloticus). METHODS AND RESULTS We eliminated the virulence factor, sialic acid (Sia) encoded by the neuA-D gene cluster from the Group B Streptococcus (Streptococcus agalactiae, GBS) strain WC1535, to construct Sia-deficient S. agalactiae (ΔSia) mutant by homologous recombination. Results showed that the ΔSia mutant had higher adherence to HEp-2 cells and lower resistance to RAW264.7 cell phagocytosis than the wild-type S. agalactiae. The virulence of the ΔSia mutant to tilapia dramatically decreased with no virulence recovery. The relative percent survivals (RPSs) were 50.00% and 54.50% at 30 days when challenged at the wild-type WC1535 doses of 1.0 × 107 and 5.0 × 107 CFU fish-1 , respectively, via intraperitoneal (IP) injection. The tilapia vaccinated via IP injection with the ΔSia mutant induced strong antibody agglutination titers. The expression of IL-1β, TNF-α, MHC-Iα, and MHC-IIβ could be enhanced in the intestine, spleen, and head kidney for tilapia administered with the ΔSia mutant. CONCLUSIONS GBS Sia plays a critical role in adherence to HEp-2 cells and resistance to the immune clearance of RAW264.7 cells. Moreover, the ΔSia mutant is a safe, stable, and immunogenic live attenuated vaccine candidate to protect tilapia against GBS infection. SIGNIFICANCE AND IMPACT OF STUDY The results offer more evidence of the importance of Sia in GBS and may be instructive in the control of tilapia streptococcosis.
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Affiliation(s)
- Jingwen Hao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shuyi Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | | | - Qianqian Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhenbing Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yaoyao Lin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | | | - Jinyong Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Defeng Zhang
- Key Laboratory of Fishery Drug Development, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Aihua Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
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8
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Abstract
Neonatal bacterial meningitis is a devastating disease, associated with high mortality and neurological disability, in both developed and developing countries. Streptococcus agalactiae, commonly referred to as group B Streptococcus (GBS), remains the most common bacterial cause of meningitis among infants younger than 90 days. Maternal colonization with GBS in the gastrointestinal and/or genitourinary tracts is the primary risk factor for neonatal invasive disease. Despite prophylactic intrapartum antibiotic administration to colonized women and improved neonatal intensive care, the incidence and morbidity associated with GBS meningitis have not declined since the 1970s. Among meningitis survivors, a significant number suffer from complex neurological or neuropsychiatric sequelae, implying that the pathophysiology and pathogenic mechanisms leading to brain injury and devastating outcomes are not yet fully understood. It is imperative to develop new therapeutic and neuroprotective approaches aiming at protecting the developing brain. In this review, we provide updated clinical information regarding the understanding of neonatal GBS meningitis, including epidemiology, diagnosis, management, and human evidence of the disease's underlying mechanisms. Finally, we explore the experimental models used to study GBS meningitis and discuss their clinical and physiologic relevance to the complexities of human disease.
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Affiliation(s)
- Teresa Tavares
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Liliana Pinho
- Centro Hospitalar Universitário do Porto, Centro Materno Infantil do Norte, Porto, Portugal
| | - Elva Bonifácio Andrade
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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Furuta A, Brokaw A, Manuel G, Dacanay M, Marcell L, Seepersaud R, Rajagopal L, Adams Waldorf K. Bacterial and Host Determinants of Group B Streptococcal Infection of the Neonate and Infant. Front Microbiol 2022; 13:820365. [PMID: 35265059 PMCID: PMC8899651 DOI: 10.3389/fmicb.2022.820365] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/27/2022] [Indexed: 12/15/2022] Open
Abstract
Group B streptococci (GBS) are Gram-positive β-hemolytic bacteria that can cause serious and life-threatening infections in neonates manifesting as sepsis, pneumonia, meningitis, osteomyelitis, and/or septic arthritis. Invasive GBS infections in neonates in the first week of life are referred to as early-onset disease (EOD) and thought to be acquired by the fetus through exposure to GBS in utero or to vaginal fluids during birth. Late-onset disease (LOD) refers to invasive GBS infections between 7 and 89 days of life. LOD transmission routes are incompletely understood, but may include breast milk, household contacts, nosocomial, or community sources. Invasive GBS infections and particularly meningitis may result in significant neurodevelopmental injury and long-term disability that persists into childhood and adulthood. Globally, EOD and LOD occur in more than 300,000 neonates and infants annually, resulting in 90,000 infant deaths and leaving more than 10,000 infants with a lifelong disability. In this review, we discuss the clinical impact of invasive GBS neonatal infections and then summarize virulence and host factors that allow the bacteria to exploit the developing neonatal immune system and target organs. Specifically, we consider the mechanisms known to enable GBS invasion into the neonatal lung, blood vessels and brain. Understanding mechanisms of GBS invasion and pathogenesis relevant to infections in the neonate and infant may inform the development of therapeutics to prevent or mitigate injury, as well as improve risk stratification.
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Affiliation(s)
- 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
| | - 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
| | - Gygeria Manuel
- Morehouse School of Medicine, Atlanta, GA, United States
| | - Matthew Dacanay
- Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, United States
| | - Lauren Marcell
- Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, United States
| | - Ravin Seepersaud
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, 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 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, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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10
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Tsubata T. Role of inhibitory B cell co-receptors in B cell self-tolerance to non-protein antigens. Immunol Rev 2022; 307:53-65. [PMID: 34989000 DOI: 10.1111/imr.13059] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 12/14/2022]
Abstract
Antibodies to non-protein antigens such as nucleic acids, polysaccharides, and glycolipids play important roles in both host defense against microbes and development of autoimmune diseases. Although non-protein antigens are not recognized by T cells, antibody production to non-protein antigens involve T cell-independent mechanisms such as signaling through TLR7 and TLR9 in antibody production to nucleic acids. Although self-reactive B cells are tolerized by various mechanisms including deletion, anergy, and receptor editing, T cell tolerance is also crucial in self-tolerance of B cells to protein self-antigen because self-reactive T cells induce autoantibody production to these self-antigens. However, presence of T cell-independent mechanism suggests that T cell tolerance is not able to maintain B cell tolerance to non-protein self-antigens. Lines of evidence suggest that B cell response to non-protein self-antigens such as nucleic acids and gangliosides, sialic acid-containing glycolipids, are suppressed by inhibitory B cell co-receptors CD72 and Siglec-G, respectively. These inhibitory co-receptors recognize non-protein self-antigens and suppress BCR signaling induced by these antigens, thereby inhibiting B cell response to these self-antigens. Inhibitory B cell co-receptors appear to be involved in B cell self-tolerance to non-protein self-antigens that can activate B cells by T cell-independent mechanisms.
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Affiliation(s)
- Takeshi Tsubata
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
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11
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Karmakar J, Mukherjee K, Mandal C. Siglecs Modulate Activities of Immune Cells Through Positive and Negative Regulation of ROS Generation. Front Immunol 2021; 12:758588. [PMID: 34804046 PMCID: PMC8595208 DOI: 10.3389/fimmu.2021.758588] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 10/18/2021] [Indexed: 12/13/2022] Open
Abstract
Reactive oxygen species (ROS) are a group of oxygen-containing highly-reactive molecules produced from oxidative metabolic processes or in response to intracellular signals like cytokines and external stimuli like pathogen attack. They regulate a range of physiological processes and are involved in innate immune responses against infectious agents. Deregulation of ROS contributes to a plethora of disease conditions. Sialic acids are carbohydrates, present on cell surfaces or soluble proteins. Sialic acid-binding immunoglobulin-like lectins (Siglecs) recognize and bind to sialic acids. These are widely expressed on various types of immune cells. Siglecs modulate immune activation and can promote or inhibit ROS generation under different contexts. Siglecs promote ROS-dependent cell death in neutrophils and eosinophils while limiting oxidative stress associated with chronic obstructive pulmonary disease (COPD), sickle cell disease (SCD), coronavirus disease-2019 (COVID-19), etc. This review distinguishes itself in summarizing the current understanding of the role of Siglecs in moderating ROS production and their distinct effect on different immune cells; that ultimately determine the cellular response and the disease outcome. This is an important field of investigation having scope for both expansion and medical importance.
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Affiliation(s)
| | | | - Chitra Mandal
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology, Kolkata, India
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12
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Research Advances on Tilapia Streptococcosis. Pathogens 2021; 10:pathogens10050558. [PMID: 34066313 PMCID: PMC8148123 DOI: 10.3390/pathogens10050558] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 12/14/2022] Open
Abstract
Streptococcus agalactiae, often referred to as group B streptococci (GBS), is a severe pathogen that can infect humans as well as other animals, including tilapia, which is extremely popular in commercial aquaculture. This pathogen causes enormous pecuniary loss, and typical symptoms of streptococcosis—the disease caused by S. agalactiae—include abnormal behavior, exophthalmos, and meningitis, among others. Multiple studies have examined virulence factors associated with S. agalactiae infection, and vaccines were explored, including studies of subunit vaccines. Known virulence factors include capsular polysaccharide (CPS), hemolysin, Christie-Atkins-Munch-Peterson (CAMP) factor, hyaluronidase (HAase), superoxide dismutase (SOD), and serine-threonine protein kinase (STPK), and effective vaccine antigens reported to date include GapA, Sip, OCT, PGK, FbsA, and EF-Tu. In this review, I summarize findings from several studies about the etiology, pathology, virulence factors, and vaccine prospects for S. agalactiae. I end by considering which research areas are likely to yield success in the prevention and treatment of tilapia streptococcosis.
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13
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Potential role of the gut microbiota in neuromyelitis optica spectrum disorder: Implication for intervention. J Clin Neurosci 2020; 82:193-199. [PMID: 33257156 DOI: 10.1016/j.jocn.2020.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/22/2020] [Accepted: 11/01/2020] [Indexed: 12/19/2022]
Abstract
The gut microbiota plays an important role in the occurrence and development of neuroimmunological diseases. Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system that is characterized by the peripheral production of the disease-specific serum autoantibody aquaporin-4 (AQP4)-IgG. Recently, accumulating evidence has provided insights into the associations of gut microbiota dysbiosis and intestinal mucosal barrier destruction with NMOSD, but the underlying pathogenesis remains unclear. Thus, a microbiota intervention might be a potential therapeutic strategy for NMOSD by regulating the gut microbiota, repairing the intestinal mucosal barrier, and modulating intestinal immunity and peripheral immunity.
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14
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Nabavinia M, Khalili MB, Sadeh M, Eslami G, Vakili M, Azartoos N, Mojibiyan M. Distribution of Pilus island and antibiotic resistance genes in Streptococcus agalactiae obtained from vagina of pregnant women in Yazd, Iran. IRANIAN JOURNAL OF MICROBIOLOGY 2020; 12:411-416. [PMID: 33603995 PMCID: PMC7867704 DOI: 10.18502/ijm.v12i5.4601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Background and Objectives: Due to the important role of Streptococcus agalactiae, Group B streptococci (GBS), in production of invasive disease in neonates, investigation regarding the pathogenicity and antibiotic resistance factors is necessary in selecting the appropriate therapeutic agents. Beside capsule, the pilus has been currently recognized as an important factor in enhancing the pathogenicity of GBS. Resistance of GBS to selected antibiotics is noticeably increasing which is mainly due to the anomalous use of these drugs for treatment. The aim of this study was to determine the prevalence of pili genes followed by antibiotic susceptibility of GBS, previously serotyped, isolated from pregnant women in the city of Yazd, Iran. Materials and Methods: Fifty seven GBS from pregnant women were subjected to multiplex PCR for determination of PI-1, PI-2a and PI-2b pilus-islands and simultaneously, the phenotype of antibiotic resistance to penicillin, tetracycline, erythromycin, clindamycin, gentamycin and levofloxacin was determined. Antibiotic resistance genes (ermA, ermB, mefA, tetM, int-Tn) were further diagnosed using PCR and multiplex PCR. Results: PI-1+PI-2a with 71.9%; followed by PI-2a (21.1%) and PI-2b (7%) were observed. PI-1+PI-2a in serotype III was (73.2%), serotype II, Ia, Ib and V were 12.2%, 9.8%, 2.4% and 2.4% respectively. GBS penicillin sensitive was 89.5% and 96.5% resistance to tetracycline. The frequency of resistance genes were as follows: tetM (93%), ermA (33.3%), ermB (8.8%), int-Tn (80.7%) and mefA (0). Conclusion: Majority of GBS contained PI-1+PI-2a. Hence presence of this pilus stabilizes the colonization, therefore designing a program for diagnosing and treatment of infected pregnant women seems to be necessary.
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Affiliation(s)
- Mahdieh Nabavinia
- Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Bagher Khalili
- Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Maryam Sadeh
- Department of Laboratory Sciences, Faculty of Paramedical Sciences, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Gilda Eslami
- Department of Parasitology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mahmood Vakili
- Department of Public Medicine, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Nastaran Azartoos
- Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mahdiye Mojibiyan
- Department of Obstetrics and Gynecology, Mojibiyan Hospital, Yazd, Iran
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15
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Phylogeny, recombination, and invasiveness of group B Streptococcus revealed by genomic comparisons of its global strains. Eur J Clin Microbiol Infect Dis 2020; 40:581-590. [PMID: 33067737 PMCID: PMC7567417 DOI: 10.1007/s10096-020-04067-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 10/09/2020] [Indexed: 11/26/2022]
Abstract
Capsular polysaccharide (CPS) genes and pilus islands encode important virulence factors for group B Streptococcus (GBS) genomes. This study aims to detect phylogenetic inconsistency in CPS genes and pilus islands in GBSs and to explore its relationship with invasiveness. A total of 1016 GBS genomes were downloaded from the NCBI public database. The multi-locus sequence typing (MLST) and Bayesian analysis of Population Structure (BAPS) analyses were both conducted for phylogeny construction. Serotyping and pilus typing were determined in silico using the genomic sequences. The CPS and pilus typing results were generally consistent with MLST and BAPS clustering. GBS isolates of serotype II and of the PI-1 + PI-2b and PI-2a types were more prone to phylogenetic inconsistency than the others. Isolates of serotype Ib and of PI-1 + PI-2a were more likely to appear as colonizing strains, whereas PI-2b was more likely to appear in invasive strains. For serotype V, phylogenetic inconsistency occurred more commonly in colonizing isolates, while for serotype III, the opposite occurred. The present study profiles for the first time the phylogenetic inconsistency of CPS genes and pilus islands in global GBS isolates, which is helpful for infection control and the development of new vaccines for the prevention of GBS occurrence.
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16
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Laut CL, Perry WJ, Metzger AL, Weiss A, Stauff DL, Walker S, Caprioli RM, Skaar EP. Bacillus anthracis Responds to Targocil-Induced Envelope Damage through EdsRS Activation of Cardiolipin Synthesis. mBio 2020; 11:e03375-19. [PMID: 32234818 PMCID: PMC7157781 DOI: 10.1128/mbio.03375-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 02/27/2020] [Indexed: 01/08/2023] Open
Abstract
Bacillus anthracis is a spore-forming bacterium that causes devastating infections and has been used as a bioterror agent. This pathogen can survive hostile environments through the signaling activity of two-component systems, which couple environmental sensing with transcriptional activation to initiate a coordinated response to stress. In this work, we describe the identification of a two-component system, EdsRS, which mediates the B. anthracis response to the antimicrobial compound targocil. Targocil is a cell envelope-targeting compound that is toxic to B. anthracis at high concentrations. Exposure to targocil causes damage to the cellular barrier and activates EdsRS to induce expression of a previously uncharacterized cardiolipin synthase, which we have named ClsT. Both EdsRS and ClsT are required for protection against targocil-dependent damage. Induction of clsT by EdsRS during targocil treatment results in an increase in cardiolipin levels, which protects B. anthracis from envelope damage. Together, these results reveal that a two-component system signaling response to an envelope-targeting antimicrobial induces production of a phospholipid associated with stabilization of the membrane. Cardiolipin is then used to repair envelope damage and promote B. anthracis viability.IMPORTANCE Compromising the integrity of the bacterial cell barrier is a common action of antimicrobials. Targocil is an antimicrobial that is active against the bacterial envelope. We hypothesized that Bacillus anthracis, a potential weapon of bioterror, senses and responds to targocil to alleviate targocil-dependent cell damage. Here, we show that targocil treatment increases the permeability of the cellular envelope and is particularly toxic to B. anthracis spores during outgrowth. In vegetative cells, two-component system signaling through EdsRS is activated by targocil. This results in an increase in the production of cardiolipin via a cardiolipin synthase, ClsT, which restores the loss of barrier function, thereby reducing the effectiveness of targocil. By elucidating the B. anthracis response to targocil, we have uncovered an intrinsic mechanism that this pathogen employs to resist toxicity and have revealed therapeutic targets that are important for bacterial defense against structural damage.
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Affiliation(s)
- Clare L Laut
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - William J Perry
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee, USA
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Andy Weiss
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Devin L Stauff
- Department of Biology, Grove City College, Grove City, Pennsylvania, USA
| | - Suzanne Walker
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Richard M Caprioli
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee, USA
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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17
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Abstract
Siglecs are sialic acid (Sia) recognizing immunoglobulin-like receptors expressed on the surface of all the major leukocyte lineages in mammals. Siglecs recognize ubiquitous Sia epitopes on various glycoconjugates in the cell glycocalyx and transduce signals to regulate immunological and inflammatory activities of these cells. The subset known as CD33-related Siglecs is principally inhibitory receptors that suppress leukocyte activation, and recent research has shown that a number of bacterial pathogens use Sia mimicry to engage these Siglecs as an immune evasion strategy. Conversely, Siglec-1 is a macrophage phagocytic receptor that engages GBS and other sialylated bacteria to promote effective phagocytosis and antigen presentation for the adaptive immune response, whereas certain viruses and parasites use Siglec-1 to gain entry to immune cells as a proximal step in the infectious process. Siglecs are positioned in crosstalk with other host innate immune sensing pathways to modulate the immune response to infection in complex ways. This chapter summarizes the current understanding of Siglecs at the host-pathogen interface, a field of study expanding in breadth and medical importance, and which provides potential targets for immune-based anti-infective strategies.
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Affiliation(s)
- Yung-Chi Chang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen-Ai Rd., Taipei, 10051, Taiwan.
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, and Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, 9500 Gilman Drive Mail Code 0760, La Jolla, CA, 92093, USA
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18
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Gendrin C, Merillat S, Vornhagen J, Coleman M, Armistead B, Ngo L, Aggarwal A, Quach P, Berrigan J, Rajagopal L. Diminished Capsule Exacerbates Virulence, Blood-Brain Barrier Penetration, Intracellular Persistence, and Antibiotic Evasion of Hyperhemolytic Group B Streptococci. J Infect Dis 2019; 217:1128-1138. [PMID: 29301010 DOI: 10.1093/infdis/jix684] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/28/2017] [Indexed: 12/21/2022] Open
Abstract
Group B streptococci (GBS) are encapsulated, β-hemolytic bacteria that are a common cause of infections in human newborns and certain adults. Two factors important for GBS virulence are the sialic acid capsular polysaccharide that promotes immune evasion and the hemolytic pigment that induces host cell cytotoxcity. These virulence factors are often oppositely regulated by the CovR/CovS two-component system. Clinical GBS strains exhibiting hyperhemolysis and low capsule due to pathoadaptive covR/S mutations have been isolated from patients. Given the importance of capsule to GBS virulence, we predicted that a decrease or loss of capsule would attenuate the virulence of covR/S mutants. Surprisingly, hyperhemolytic GBS with low or no capsule exhibit increased virulence, intracellular persistence, and blood-brain barrier penetration, which was independent of a Trojan horse mechanism of barrier penetration. Additionally, intracellular persistence enabled both hemolytic and hyperhemolytic GBS to evade antibiotics routinely used to treat these infections. The finding that diminished capsule expression promotes GBS virulence, intracellular persistence, and antibiotic evasion has important implications for sustained antibiotic therapy and efficacy of capsule-based vaccines.
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Affiliation(s)
- Claire Gendrin
- Department of Pediatrics, University of Washington.,Center for Global Infections Disease Research, Seattle Children's Research Institute
| | - Sean Merillat
- Center for Global Infections Disease Research, Seattle Children's Research Institute
| | - Jay Vornhagen
- Department of Pediatrics, University of Washington.,Center for Global Infections Disease Research, Seattle Children's Research Institute.,Department of Global Health, University of Washington, Seattle
| | - Michelle Coleman
- Department of Pediatrics, University of Washington.,Center for Global Infections Disease Research, Seattle Children's Research Institute
| | - Blair Armistead
- Department of Pediatrics, University of Washington.,Center for Global Infections Disease Research, Seattle Children's Research Institute.,Department of Global Health, University of Washington, Seattle
| | - Lisa Ngo
- Center for Global Infections Disease Research, Seattle Children's Research Institute
| | - Anjali Aggarwal
- Center for Global Infections Disease Research, Seattle Children's Research Institute
| | - Phoenicia Quach
- Center for Global Infections Disease Research, Seattle Children's Research Institute
| | - Jacob Berrigan
- Center for Global Infections Disease Research, Seattle Children's Research Institute
| | - Lakshmi Rajagopal
- Department of Pediatrics, University of Washington.,Center for Global Infections Disease Research, Seattle Children's Research Institute.,Department of Global Health, University of Washington, Seattle
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19
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Parida R. Human MOSPD2: A bacterial Lmb mimicked auto-antigen is involved in immune infertility. J Transl Autoimmun 2019; 1:100002. [PMID: 32743492 PMCID: PMC7388392 DOI: 10.1016/j.jtauto.2019.100002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 05/16/2019] [Accepted: 05/19/2019] [Indexed: 12/12/2022] Open
Abstract
Autoantibody production is one of the leading factors of immune infertility, an autoimmune disease of the male reproductive system. The potential involvement of MHC-class II derived self-peptides against bacterial proteins in the antisperm antibody (ASA) production has been reported previously. Apparently, Streptococcus agalactiae has been considered as an important pathogen to impart infection-induced infertility in a bacteriospermia associated leukocytospermia (LCS/BS) state. Hence, the present study attempts to confirm S. agalactiae specific Laminin binding protein (Lmb) derived self-peptide ('KDSYTKKAKAFKKEA') namely human Motile Sperm domain-containing protein 2 (MOSPD2) as an auto-antigen in LCS/BS condition. Semen samples were collected from infertile men with LCS/BS (n = 17) and their fertile counterparts (n = 10). Gram-positive bacteria were predominantly identified in the entire 17 LCS samples using culture method followed by 16S rDNA sequencing technique. TLRs 2 and 4 expression used as markers of immune response in spermatozoa and sperm dysfunction were elevated in the LCS/BS spermatozoa as compared to their fertile counterparts. A significant increase in oxidative stress indices i.e., protein carbonylation, lipid peroxidation and acridine orange test (AOT), was also observed in the LCS/BS spermatozoa. Spermatozoa lysate (both auto and heterologous), bacterial lysate (control) and synthesized MOSPD2 self-peptide were used to test their antigenicity against the autoantibodies by rocket immunoelectrophoresis (RIEP) assay. Seminal plasma from LCS/BS patients with S. agalactiae was used as the source of autoantibodies. Spermatozoa and bacteria lysate; and MOSPD2 self-peptide were able to bind autoantibodies in the seminal plasma. Besides, the self-peptide showed a dose dependent increase in the precipitation of antibody. T-cell epitope mapping of 48 Enterococcus faecalis and 91Staphylococcus aureus surface proteins confirmed MOSPD2 as a global auto-antigen. Thus, augmentation of TLR expression in LCS/BS spermatozoa inferred MOSPD2 to be a putative immunogen. Altogether, these findings will delineate the significance of MOSPD2 auto-antigen in a bacteria derived immune infertility condition.
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Affiliation(s)
- Rajeshwari Parida
- Department of Zoology, Ravenshaw University, Cuttack, 753003, Odisha, India
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20
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Abstract
The surface of the Gram-positive opportunistic pathogen Streptococcus agalactiae, or group B Streptococcus (GBS), harbors several carbohydrate and protein antigens with the potential to be effective vaccines. Capsular polysaccharides of all clinically-relevant GBS serotypes coupled to immunogenic proteins of both GBS and non-GBS origin have undergone extensive testing in animals that led to advanced clinical trials in healthy adult women. In addition, GBS proteins either alone or in combination have been tested in animals; a fusion protein construct has recently advanced to human clinical studies. Given our current understanding of the antigenicity and immunogenicity of the wide array of GBS surface antigens, formulations now exist for the generation of viable vaccines against diseases caused by GBS.
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21
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Tian XY, Zheng N, Han RW, Ho H, Wang J, Wang YT, Wang SQ, Li HG, Liu HW, Yu ZN. Antimicrobial resistance and virulence genes of Streptococcus isolated from dairy cows with mastitis in China. Microb Pathog 2019; 131:33-39. [PMID: 30940606 DOI: 10.1016/j.micpath.2019.03.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 11/18/2022]
Abstract
Streptococcus is a major mastitis-causing pathogen in dairy cows. To investigate the prevalence, antimicrobial resistance and virulence gene of Streptococcus in mastitic milk, a total of 735 mastitic raw milk samples from dairy cows in 11 provinces of China were collected and tested. Antimicrobial resistance of Streptococcus isolates was determined by disc diffusion against 8 classes 29 antimicrobial agents, and Streptococcus resistant genes and virulence genes were determined by PCR and agarose gel electrophoresis. A total of 64 (8.71%) isolates of Streptococcus were isolated and identified using biochemical profiling, including 22 isolates of Streptococcus agalactiae, 13 isolates of Streptococcus dysgalactiae, and 29 isolates of Streptococcus uberis. Out of 64 resistant Streptococcus isolates, all isolates (100%) were resistant to 3 or more antimicrobials. The most frequency (n = 18, 28.12%) of the isolates were multi-resistant to 5-7 antimicrobials and the highest multi-resistant number was 29 (n = 1, 1.56%). Streptococcus isolates had the highest resistance rate to tetracycline (98.44%) and oxacillin (98.44%), followed by penicillin G (96.88%) and doxycycline (96.88%), and the lowest resistance was observed with respect to ciprofloxacin (1.56%). A total of 16 antimicrobials resistance genes with 25 combination patterns were detected in the isolates. The gene combination of Sul1/Sul2/Sul3 + gyrA/parC + cat1/cat2 was the most common pattern (12.5%). The correlation between resistant phenotypes and resistance genes in Streptococcs was 35.87%. A total of 7 virulence genes were detected and 59 (92.19%) isolates harbored at least one gene. Twenty-four classes of gene patterns were found in the isolates and the patterns of bca (9.38%) and cfb (9.38%) were the most prevalent form. In conclusion, the issue of drug resistance of Streptococcus is still a great concern in cattle health in China.
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Affiliation(s)
- X Y Tian
- College of Food Science and Technology, Qingdao Agricultural University, Qingdao, 266109, PR China.
| | - N Zheng
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
| | - R W Han
- College of Food Science and Technology, Qingdao Agricultural University, Qingdao, 266109, PR China.
| | - H Ho
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
| | - J Wang
- College of Food Science and Technology, Qingdao Agricultural University, Qingdao, 266109, PR China.
| | - Y T Wang
- Institute of Quality Standard and Test Technology for Agro-products, Shandong Academy of Agricultural Sciences, Jinan, 250100, PR China.
| | - S Q Wang
- College of Food Science and Technology, Qingdao Agricultural University, Qingdao, 266109, PR China.
| | - H G Li
- College of Food Science and Technology, Qingdao Agricultural University, Qingdao, 266109, PR China.
| | - H W Liu
- College of Food Science and Technology, Qingdao Agricultural University, Qingdao, 266109, PR China.
| | - Z N Yu
- Haidu College.Qingdao Agricultural University, Laiyang, 265200, PR China.
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22
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Dual actions of group B Streptococcus capsular sialic acid provide resistance to platelet-mediated antimicrobial killing. Proc Natl Acad Sci U S A 2019; 116:7465-7470. [PMID: 30910970 DOI: 10.1073/pnas.1815572116] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Circulating platelets have important functions in thrombosis and in modulating immune and inflammatory responses. However, the role of platelets in innate immunity to bacterial infection is largely unexplored. While human platelets rapidly kill Staphylococcus aureus, we found the neonatal pathogen group B Streptococcus (GBS) to be remarkably resistant to platelet killing. GBS possesses a capsule polysaccharide (CPS) with terminal α2,3-linked sialic acid (Sia) residues that mimic a common epitope present on the human cell surface glycocalyx. A GBS mutant deficient in CPS Sia was more efficiently killed by human platelets, thrombin-activated platelet releasate, and synthetic platelet-associated antimicrobial peptides. GBS Sia is known to bind inhibitory Sia-recognizing Ig superfamily lectins (Siglecs) to block neutrophil and macrophage activation. We show that human platelets also express high levels of inhibitory Siglec-9 on their surface, and that GBS can engage this receptor in a Sia-dependent manner to suppress platelet activation. In a mouse i.v. infection model, antibody-mediated platelet depletion increased susceptibility to platelet-sensitive S. aureus but did not alter susceptibility to platelet-resistant GBS. Elimination of murine inhibitory Siglec-E partially reversed platelet suppression in response to GBS infection. We conclude that GBS Sia has dual roles in counteracting platelet antimicrobial immunity: conferring intrinsic resistance to platelet-derived antimicrobial components and inhibiting platelet activation through engagement of inhibitory Siglecs. We report a bacterial virulence factor for evasion of platelet-mediated innate immunity.
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23
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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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24
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Perinatal Streptococcus agalactiae Epidemiology and Surveillance Targets. Clin Microbiol Rev 2018; 31:31/4/e00049-18. [PMID: 30111577 DOI: 10.1128/cmr.00049-18] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus agalactiae, or group B streptococcus (GBS), is a major neonatal pathogen. Recent data have elucidated the global prevalence of maternal and neonatal colonization, but gaps still remain in the epidemiology of this species. A number of phenotypic and genotypic classifications can be used to identify the diversity of GBS strains, and some are more discriminatory than others. This review explores the main schemes used for GBS epidemiology and further details the targets for epidemiological surveillance. Current screening practices across the world provide a unique opportunity to gain detailed information on maternal colonizing strains and neonatal disease-causing strains, which is vital for monitoring and therapeutics, if sufficient detail can be extracted. Deciphering which isolates are circulating within specific populations and recording targets within invasive strains are crucial steps in monitoring the implementation of therapeutics, such as vaccines, as well as developing novel therapies against prevalent GBS strains. Having a detailed understanding of global GBS epidemiology will prove invaluable for understanding the pathogenesis of this organism and equipping future prevention strategies for success.
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25
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Tong J, Fu Y, Wu NH, Rohde M, Meng F, Valentin-Weigand P, Herrler G. Sialic acid-dependent interaction of group B streptococci with influenza virus-infected cells reveals a novel adherence and invasion mechanism. Cell Microbiol 2018; 20. [DOI: 10.1111/cmi.12818] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/10/2017] [Accepted: 12/01/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Jie Tong
- Institute of Virology; University of Veterinary Medicine Hannover; Hannover Germany
| | - Yuguang Fu
- Institute of Virology; University of Veterinary Medicine Hannover; Hannover Germany
- Chinese Academy of Agricultural Sciences, Lanzhou Veterinary Research Institute; State Key Laboratory of Veterinary Etiological Biology; Lanzhou Gansu Province China
| | - Nai-Huei Wu
- Institute of Virology; University of Veterinary Medicine Hannover; Hannover Germany
| | - Manfred Rohde
- Central Facility for Microscopy; Helmholtz Centre for Infection Research, HZI; Braunschweig Germany
| | - Fandan Meng
- Institute of Virology; University of Veterinary Medicine Hannover; Hannover Germany
| | | | - Georg Herrler
- Institute of Virology; University of Veterinary Medicine Hannover; Hannover Germany
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Ono E, Uede T. Implication of Soluble Forms of Cell Adhesion Molecules in Infectious Disease and Tumor: Insights from Transgenic Animal Models. Int J Mol Sci 2018; 19:ijms19010239. [PMID: 29342882 PMCID: PMC5796187 DOI: 10.3390/ijms19010239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 01/10/2018] [Accepted: 01/12/2018] [Indexed: 12/26/2022] Open
Abstract
Cell adhesion molecules (CAMs) are surface ligands, usually glycoproteins, which mediate cell-to-cell adhesion. They play a critical role in maintaining tissue integrity and mediating migration of cells, and some of them also act as viral receptors. It has been known that soluble forms of the viral receptors bind to the surface glycoproteins of the viruses and neutralize them, resulting in inhibition of the viral entry into cells. Nectin-1 is one of important CAMs belonging to immunoglobulin superfamily and herpesvirus entry mediator (HVEM) is a member of the tumor necrosis factor (TNF) receptor family. Both CAMs also act as alphaherpesvirus receptor. Transgenic mice expressing the soluble form of nectin-1 or HVEM showed almost complete resistance against the alphaherpesviruses. As another CAM, sialic acid-binding immunoglobulin-like lectins (Siglecs) that recognize sialic acids are also known as an immunoglobulin superfamily member. Siglecs play an important role in the regulation of immune cell functions in infectious diseases, inflammation, neurodegeneration, autoimmune diseases and cancer. Siglec-9 is one of Siglecs and capsular polysaccharide (CPS) of group B Streptococcus (GBS) binds to Siglec-9 on neutrophils, leading to suppress host immune response and provide a survival advantage to the pathogen. In addition, Siglec-9 also binds to tumor-produced mucins such as MUC1 to lead negative immunomodulation. Transgenic mice expressing the soluble form of Siglec-9 showed significant resistance against GBS infection and remarkable suppression of MUC1 expressing tumor proliferation. This review describes recent developments in the understanding of the potency of soluble forms of CAMs in the transgenic mice and discusses potential therapeutic interventions that may alter the outcomes of certain diseases.
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Affiliation(s)
- Etsuro Ono
- Department of Biomedicine, Center of Biomedical Research, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
| | - Toshimitsu Uede
- Division of Molecular Immunology, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.
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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: 90] [Impact Index Per Article: 15.0] [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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28
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Intrinsic Maturational Neonatal Immune Deficiencies and Susceptibility to Group B Streptococcus Infection. Clin Microbiol Rev 2017; 30:973-989. [PMID: 28814408 DOI: 10.1128/cmr.00019-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although a normal member of the gastrointestinal and vaginal microbiota, group B Streptococcus (GBS) can also occasionally be the cause of highly invasive neonatal disease and is an emerging pathogen in both elderly and immunocompromised adults. Neonatal GBS infections are typically transmitted from mother to baby either in utero or during passage through the birth canal and can lead to pneumonia, sepsis, and meningitis within the first few months of life. Compared to the adult immune system, the neonatal immune system has a number of deficiencies, making neonates more susceptible to infection. Recognition of GBS by the host immune system triggers an inflammatory response to clear the pathogen. However, GBS has developed several mechanisms to evade the host immune response. A comprehensive understanding of this interplay between GBS and the host immune system will aid in the development of new preventative measures and therapeutics.
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29
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Gallage S, Katagiri T, Endo M, Maita M. Comprehensive evaluation of immunomodulation by moderate hypoxia in S. agalactiae vaccinated Nile tilapia. FISH & SHELLFISH IMMUNOLOGY 2017; 66:445-454. [PMID: 28526572 DOI: 10.1016/j.fsi.2017.05.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 05/15/2017] [Accepted: 05/15/2017] [Indexed: 06/07/2023]
Abstract
Streptococcus agalactiae is a major bacterial pathogen in tilapia aquaculture. Vaccines are known to provide protection but S. agalactiae clearance in tilapia can be reduced by marginal environmental conditions. Therefore, the purpose of this study is to examine S. agalactiae clearance in vaccinated Nile tilapia under moderate hypoxic (55± 5% DO) and normoxic (85 ± 5%DO) conditions. Fish were acclimatized to either moderate hypoxia or normoxia and immunized with formalin-inactivated S. agalactiae. Fish were experimentally challenged with S. agalactiae at 30 days post-vaccination. Serum antibody titer was significantly higher in vaccinated fish kept under normoxic condition compared to the moderate hypoxic condition at fifteen and thirty days post-vaccination. The cumulative mortality following challenge was significantly reduced in vaccinated fish kept under normoxic condition compared to those in moderate hypoxic condition reflecting that pre-challenge antibody titer may correlate with survival of fish. Blood and tissue pathogen burden detection of S. agalactiae studies revealed that culturable S. agalactiae cells could not be detected in the blood of normoxic vaccinated fish at all the sampling points. In contrast, fish vaccinated in moderate hypoxic condition had considerable number of culturable S. agalactiae cells in their blood up to 5 days following challenge. Phagocytosis and intracellular reactive oxygen species (ROS) production were lowered by moderate hypoxia in vitro. Furthermore, presence of specific antibodies and higher specific antibody level in the serum increased phagocytosis, ROS production and lowered intracellular survival of S. agalactiae in head kidney leukocytes. Overall this study has highlighted that S. agalactiae clearance in vaccinated Nile tilapia is modulated by moderate hypoxia. One of the possible explanations for this might be less efficient phagocytic activities due to low oxygen availability and lower specific antibody production in vaccinated fish.
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Affiliation(s)
- Sanchala Gallage
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
| | - Takayuki Katagiri
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
| | - Masato Endo
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
| | - Masashi Maita
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
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A soluble form of Siglec-9 provides a resistance against Group B Streptococcus (GBS) infection in transgenic mice. Microb Pathog 2016; 99:106-110. [DOI: 10.1016/j.micpath.2016.08.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 08/01/2016] [Accepted: 08/09/2016] [Indexed: 11/18/2022]
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31
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Epidemiology of Invasive Group B Streptococcal Disease in Alberta, Canada, from 2003 to 2013. J Clin Microbiol 2016; 54:1774-1781. [PMID: 27098960 DOI: 10.1128/jcm.00355-16] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/12/2016] [Indexed: 11/20/2022] Open
Abstract
Group B streptococci (GBS) cause severe invasive disease in both neonates and adults. Understanding the epidemiology of GBS provides information that can include determining disease prevalence rates in defined populations and geographic regions, documenting the success of GBS screening programs, and understanding antimicrobial susceptibility patterns. In Alberta, only neonatal invasive GBS (iGBS) disease is notifiable to health authorities. We performed a surveillance study of iGBS in Alberta, Canada, from 2003 to 2013. Over the 11-year period, the disease incidence rate increased from a low of 3.92 cases/100,000 population to a high of 5.99 cases/100,000 population. The capsular polysaccharide serotypes (CPSs) found were CPS III (20.3%), CPS V (19.1%), CPS Ia (18.9%), CPS Ib (12.7%), CPS II (11.1%), CPS IV (6.3%), and nontypeable GBS (9.4%). Rates of early-onset disease (0 to 7 days) increased from 0.15 cases/1,000 live births (in 2003) to 0.34 cases/1,000 live births (in 2013). Rates of late-onset disease (>7 to 90 days) also rose, from 0.15 cases/1,000 live births (in 2003) to 0.39 cases/1,000 live births (in 2013). Alberta also experienced an increase in CPS IV isolates, from 2 cases (in 2003) to 24 cases (in 2013), of which the majority were hvgA negative (93.4%) [corrected]. The predominant sequence type (ST) in 2013 was ST459. Erythromycin resistance rose from 23.6% to 43.9% (in 2013). Clindamycin resistance also increased, from 12.2% to 32.5%. In summary, Alberta, Canada, has experienced an increase in GBS disease; the increase includes both neonatal and adult disease. CPS IV cases also notably increased during the surveillance period, as did resistance to erythromycin and clindamycin.
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Pietrocola G, Rindi S, Rosini R, Buccato S, Speziale P, Margarit I. The Group B Streptococcus-Secreted Protein CIP Interacts with C4, Preventing C3b Deposition via the Lectin and Classical Complement Pathways. THE JOURNAL OF IMMUNOLOGY 2015; 196:385-94. [PMID: 26608922 DOI: 10.4049/jimmunol.1501954] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/30/2015] [Indexed: 02/06/2023]
Abstract
The group B Streptococcus (GBS) is a leading cause of neonatal invasive disease. GBS bacteria are surrounded by a thick capsular polysaccharide that is a potent inhibitor of complement deposition via the alternative pathway. Several of its surface molecules can however activate the classical and lectin complement pathways, rendering this species still vulnerable to phagocytic killing. In this study we have identified a novel secreted protein named complement interfering protein (CIP) that downregulates complement activation via the classical and lectin pathways, but not the alternative pathway. The CIP protein showed high affinity toward C4b and inhibited its interaction with C2, presumably preventing the formation of the C4bC2a convertase. Addition of recombinant CIP to GBS cip-negative bacteria resulted in decreased deposition of C3b on their surface and in diminished phagocytic killing in a whole-blood assay. Our data reveal a novel strategy exploited by GBS to counteract innate immunity and could be valuable for the development of anti-infective agents against this important pathogen.
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Affiliation(s)
- Giampiero Pietrocola
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, 27100 Pavia, Italy; and
| | - Simonetta Rindi
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, 27100 Pavia, Italy; and
| | | | | | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, 27100 Pavia, Italy; and
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Roy D, Auger JP, Segura M, Fittipaldi N, Takamatsu D, Okura M, Gottschalk M. Role of the capsular polysaccharide as a virulence factor for Streptococcus suis serotype 14. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2015; 79:141-146. [PMID: 25852230 PMCID: PMC4365706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/10/2014] [Indexed: 06/04/2023]
Abstract
Streptococcus suis is an important swine pathogen and a zoonotic agent causing meningitis and septicemia. Although serotype 2 is the most virulent type, serotype 14 is emerging, and understanding of its pathogenesis is limited. To study the role of the capsular polysaccharide (CPS) of serotype 14 as a virulence factor, we constructed knockout mutants devoid of either cps14B, a highly conserved regulatory gene, or neu14C, a gene coding for uridine diphospho-N-acetylglucosamine 2-epimerase, which is involved in sialic acid synthesis. The mutants showed total loss of the CPS with coagglutination assays and electron microscopy. Phagocytosis assays showed high susceptibility of mutant Δcps14B. An in vivo murine model was used to demonstrate attenuated virulence of this non-encapsulated mutant. Despite the difference in the CPS composition of different serotypes, this study has demonstrated for the first time that the CPS of a serotype other than 2 is also an important antiphagocytic factor and a critical virulence factor.
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Affiliation(s)
| | | | | | | | | | | | - Marcelo Gottschalk
- Address all correspondence to Dr. Marcelo Gottschalk; telephone: (450) 773-8521, ext. 8374; fax: (450) 778-8108; e-mail:
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34
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The sensor histidine kinase RgfC affects group B streptococcal virulence factor expression independent of its response regulator RgfA. Infect Immun 2015; 83:1078-88. [PMID: 25561709 DOI: 10.1128/iai.02738-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Group B streptococci (GBS; Streptococcus agalactiae) are beta-hemolytic, Gram-positive bacteria that are common asymptomatic colonizers of healthy adults. However, these opportunistic bacteria also cause invasive infections in human newborns and in certain adult populations. To adapt to the various environments encountered during its disease cycle, GBS encodes a number of two-component signaling systems. Previous studies have indicated that the TCS comprising the sensor histidine kinase RgfC and the response regulator RgfA mediate GBS binding to extracellular matrix components, such as fibrinogen. However, in certain GBS clinical isolates, a point mutation in rgfA results in premature truncation of the response regulator. The truncated RgfA protein lacks the C-terminal DNA binding domain necessary for promoter binding and gene regulation. Here, we show that deletion of rgfC in GBS strains lacking a functional RgfA increased systemic infection. Furthermore, infection with the rgfC mutant increased induction of proinflammatory signaling pathways in vivo. Phosphoproteomic analysis revealed that 19 phosphopeptides corresponding to 12 proteins were differentially phosphorylated at aspartate, cysteine, serine, threonine, or tyrosine residues in the rgfC mutant. This included aspartate phosphorylation of a tyrosine kinase, CpsD, and a transcriptional regulator. Consistent with this observation, microarray analysis of the rgfC mutant indicated that >200 genes showed altered expression compared to the isogenic wild-type strain and included transcriptional regulators, transporters, and genes previously associated with GBS pathogenesis. Our observations suggest that in the absence of RgfA, nonspecific RgfC signaling affects the expression of virulence factors and GBS pathogenesis.
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35
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Beaussart A, Péchoux C, Trieu-Cuot P, Hols P, Mistou MY, Dufrêne YF. Molecular mapping of the cell wall polysaccharides of the human pathogen Streptococcus agalactiae. NANOSCALE 2014; 6:14820-14827. [PMID: 25358409 DOI: 10.1039/c4nr05280c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The surface of many bacterial pathogens is covered with polysaccharides that play important roles in mediating pathogen-host interactions. In Streptococcus agalactiae, the capsular polysaccharide (CPS) is recognized as a major virulence factor while the group B carbohydrate (GBC) is crucial for peptidoglycan biosynthesis and cell division. Despite the important roles of CPS and GBC, there is little information available on the molecular organization of these glycopolymers on the cell surface. Here, we use atomic force microscopy (AFM) and transmission electron microscopy (TEM) to analyze the nanoscale distribution of CPS and GBC in wild-type (WT) and mutant strains of S. agalactiae. TEM analyses reveal that in WT bacteria, peptidoglycan is covered with a very thin (few nm) layer of GBC (the "pellicle") overlaid by a 15-45 nm thick layer of CPS (the "capsule"). AFM-based single-molecule mapping with specific antibody probes shows that CPS is exposed on WT cells, while it is hardly detected on mutant cells impaired in CPS production (ΔcpsE mutant). By contrast, both TEM and AFM show that CPS is over-expressed in mutant cells altered in GBC expression (ΔgbcO mutant), indicating that the production of the two surface glycopolymers is coordinated in WT cells. In addition, AFM topographic imaging and molecular mapping with specific lectin probes demonstrate that removal of CPS (ΔcpsE), but not of GBC (ΔgbcO), leads to the exposure of peptidoglycan, organized into 25 nm wide bands running parallel to the septum. These results indicate that CPS forms a homogeneous barrier protecting the underlying peptidoglycan from environmental exposure, while the presence of GBC does not prevent peptidoglycan detection. This work shows that single-molecule AFM, combined with high-resolution TEM, represents a powerful platform for analysing the molecular arrangement of the cell wall polymers of bacterial pathogens.
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Affiliation(s)
- Audrey Beaussart
- Université Catholique de Louvain, Institute of Life Sciences, B-1348 Louvain-la-Neuve, Belgium.
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36
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Abstract
Siglecs are mammalian sialic acid (Sia) recognizing immunoglobulin-like receptors expressed across the major leukocyte lineages, and function to recognize ubiquitous Sia epitopes on cell surface glycoconjugates and regulate immunological and inflammatory activities of these cells. A large subset referred to as CD33-related Siglecs are inhibitory receptors that limit leukocyte activation, and recent research has shown that the pathogen group B Streptococcus (GBS) binds to these Siglecs in Sia- and protein-dependent fashion to downregulate leukocyte bactericidal capacity. Conversely, sialoadhesin is a macrophage phagocytic receptor that engages GBS and other sialylated pathogens to promote effective phagocytosis and antigen presentation for the adaptive immune response. A variety of other important Siglec interactions with bacterial, viral and protozoan pathogens are beginning to be recognized. Siglec genes and binding specificities are rapidly evolving among primates, with key extant polymorphisms in human populations that may influence susceptibility to infection-associated disorders including chronic obstructive pulmonary disease and premature birth. This review summarizes current understanding of interactions between pathogens and Siglecs, a field of investigation that is likely to continue expanding in scope and medical importance.
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Affiliation(s)
- Yung-Chi Chang
- Glycobiology Research and Training Center Department of Pediatrics
| | - Victor Nizet
- Glycobiology Research and Training Center Department of Pediatrics Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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37
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Berti F, Campisi E, Toniolo C, Morelli L, Crotti S, Rosini R, Romano MR, Pinto V, Brogioni B, Torricelli G, Janulczyk R, Grandi G, Margarit I. Structure of the type IX group B Streptococcus capsular polysaccharide and its evolutionary relationship with types V and VII. J Biol Chem 2014; 289:23437-48. [PMID: 24990951 DOI: 10.1074/jbc.m114.567974] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Group B Streptococcus capsular polysaccharide type IX was isolated and purified, and the structure of its repeating unit was determined. Type IX capsule → 4)[NeupNAc-α-(2 → 3)-Galp-β-(1 → 4)-GlcpNAc-β-(1 → 6)]-β-GlcpNAc-(1 → 4)-β-Galp-(1 → 4)-β-Glcp-(1 → appears most similar to types VII and V, although it contains two GlcpNAc residues. Genetic analysis identified differences in cpsM, cpsO, and cpsI gene sequences as responsible for the differentiation between the three capsular polysaccharide types, leading us to hypothesize that type V emerged from a recombination event in a type IX background.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Guido Grandi
- From Novartis Vaccines Research, 53100 Siena, Italy
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38
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Cress BF, Englaender JA, He W, Kasper D, Linhardt RJ, Koffas MAG. Masquerading microbial pathogens: capsular polysaccharides mimic host-tissue molecules. FEMS Microbiol Rev 2014; 38:660-97. [PMID: 24372337 PMCID: PMC4120193 DOI: 10.1111/1574-6976.12056] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/16/2013] [Accepted: 12/19/2013] [Indexed: 11/27/2022] Open
Abstract
The increasing prevalence of antibiotic-resistant bacteria portends an impending postantibiotic age, characterized by diminishing efficacy of common antibiotics and routine application of multifaceted, complementary therapeutic approaches to treat bacterial infections, particularly multidrug-resistant organisms. The first line of defense for most bacterial pathogens consists of a physical and immunologic barrier known as the capsule, commonly composed of a viscous layer of carbohydrates that are covalently bound to the cell wall in Gram-positive bacteria or often to lipids of the outer membrane in many Gram-negative bacteria. Bacterial capsular polysaccharides are a diverse class of high molecular weight polysaccharides contributing to virulence of many human pathogens in the gut, respiratory tree, urinary tract, and other host tissues, by hiding cell surface components that might otherwise elicit host immune response. This review highlights capsular polysaccharides that are structurally identical or similar to polysaccharides found in mammalian tissues, including polysialic acid and glycosaminoglycan capsules hyaluronan, heparosan, and chondroitin. Such nonimmunogenic coatings render pathogens insensitive to certain immune responses, effectively increasing residence time in host tissues and enabling pathologically relevant population densities to be reached. Biosynthetic pathways and capsular involvement in immune system evasion are described, providing a basis for potential therapies aimed at supplementing or replacing antibiotic treatment.
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Affiliation(s)
- Brady F Cress
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
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Role of macrophage sialoadhesin in host defense against the sialylated pathogen group B Streptococcus. J Mol Med (Berl) 2014; 92:951-9. [PMID: 24788876 PMCID: PMC4133643 DOI: 10.1007/s00109-014-1157-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/23/2014] [Accepted: 04/14/2014] [Indexed: 12/01/2022]
Abstract
Abstract Several bacterial pathogens decorate their surfaces with sialic acid (Sia) residues within cell wall components or capsular exopolysaccharides. Sialic acid expression can promote bacterial virulence by blocking complement activation or by engagement of inhibitory sialic acid-binding immunoglobulin-like lectins (Siglecs) on host leukocytes. Expressed at high levels on splenic and lymph node macrophages, sialoadhesin (Sn) is a unique Siglec with an elongated structure that lacks intracellular signaling motifs. Sialoadhesin allows macrophage to engage certain sialylated pathogens and stimulate inflammatory responses, but the in vivo significance of sialoadhesin in infection has not been shown. We demonstrate that macrophages phagocytose the sialylated pathogen group B Streptococcus (GBS) and increase bactericidal activity via sialoadhesin-sialic-acid-mediated recognition. Sialoadhesin expression on marginal zone metallophillic macrophages in the spleen trapped circulating GBS and restricted the spread of the GBS to distant organs, reducing mortality. Specific IgM antibody responses to GBS challenge were also impaired in sialoadhesin-deficient mice. Thus, sialoadhesin represents a key bridge to orchestrate innate and adaptive immune defenses against invasive sialylated bacterial pathogens. Key message Sialoadhesin is critical for macrophages to phagocytose and clear GBS. Increased GBS organ dissemination in the sialoadhesin-deficient mice. Reduced anti-GBS IgM production in the sialoadhesin-deficient mice.
Electronic supplementary material The online version of this article (doi:10.1007/s00109-014-1157-y) contains supplementary material, which is available to authorized users.
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40
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Chang YC, Olson J, Beasley FC, Tung C, Zhang J, Crocker PR, Varki A, Nizet V. Group B Streptococcus engages an inhibitory Siglec through sialic acid mimicry to blunt innate immune and inflammatory responses in vivo. PLoS Pathog 2014; 10:e1003846. [PMID: 24391502 PMCID: PMC3879367 DOI: 10.1371/journal.ppat.1003846] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 11/06/2013] [Indexed: 12/15/2022] Open
Abstract
Group B Streptococcus (GBS) is a common agent of bacterial sepsis and meningitis in newborns. The GBS surface capsule contains sialic acids (Sia) that engage Sia-binding immunoglobulin-like lectins (Siglecs) on leukocytes. Here we use mice lacking Siglec-E, an inhibitory Siglec of myelomonocytic cells, to study the significance of GBS Siglec engagement during in vivo infection. We found GBS bound to Siglec-E in a Sia-specific fashion to blunt NF-κB and MAPK activation. As a consequence, Siglec-E-deficient macrophages had enhanced pro-inflammatory cytokine secretion, phagocytosis and bactericidal activity against the pathogen. Following pulmonary or low-dose intravenous GBS challenge, Siglec-E KO mice produced more pro-inflammatory cytokines and exhibited reduced GBS invasion of the central nervous system. In contrast, upon high dose lethal challenges, cytokine storm in Siglec-E KO mice was associated with accelerated mortality. We conclude that GBS Sia mimicry influences host innate immune and inflammatory responses in vivo through engagement of an inhibitory Siglec, with the ultimate outcome of the host response varying depending upon the site, stage and magnitude of infection. The bacterium Group B Streptococcus (GBS) causes serious infections such as meningitis in human newborn babies. The surface of GBS is coated with a capsule made of sugar molecules. Prominent among these is sialic acid (Sia), a human-like sugar that interacts with protein receptors called Siglecs on the surface of our white blood cells. In a test tube, GBS Sia binding to human Siglecs can suppress white blood cell activation, reducing their bacterial killing abilities; however, the significance of this during actual infection was unknown. To answer this question, we studied mice for which a key white blood cell Siglec has been genetically deleted. When infected with GBS, white blood cells from the mutant mice are not shut off by the pathogen's Sia-containing sugar capsule. The white blood cells from the Siglec-deficient mice are better at killing GBS and are able to clear infection more quickly than a normal mouse. However, if the mice are given an overwhelming dose of GBS bacteria, exaggerated white blood activation can trigger shock and more rapid death. These studies show how “molecular mimicry” of sugar molecules in the host can influence a bacterial pathogen's interaction with the immune system and the outcome of infection.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD/immunology
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/immunology
- Cytokines/genetics
- Cytokines/immunology
- Humans
- Inflammation/genetics
- Inflammation/immunology
- Inflammation/pathology
- Macrophages/immunology
- Macrophages/pathology
- Mice
- Mice, Knockout
- Molecular Mimicry/immunology
- N-Acetylneuraminic Acid/genetics
- N-Acetylneuraminic Acid/immunology
- Pneumonia, Bacterial/genetics
- Pneumonia, Bacterial/immunology
- Pneumonia, Bacterial/pathology
- Streptococcal Infections/genetics
- Streptococcal Infections/immunology
- Streptococcal Infections/pathology
- Streptococcus agalactiae/immunology
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Affiliation(s)
- Yung-Chi Chang
- Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California, United States of America
- Department of Pediatrics, University of California, San Diego, La Jolla, California, United States of America
| | - Joshua Olson
- Department of Pediatrics, University of California, San Diego, La Jolla, California, United States of America
| | - Federico C. Beasley
- Department of Pediatrics, University of California, San Diego, La Jolla, California, United States of America
| | - Christine Tung
- Department of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Jiquan Zhang
- Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Paul R. Crocker
- Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Ajit Varki
- Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California, United States of America
- Department of Medicine, University of California, San Diego, La Jolla, California, United States of America
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, United States of America
- * E-mail: (AV); (VN)
| | - Victor Nizet
- Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California, United States of America
- Department of Pediatrics, University of California, San Diego, La Jolla, California, United States of America
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
- Rady Children's Hospital, San Diego, California, United States of America
- * E-mail: (AV); (VN)
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41
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Iida KI, Seki M, Saito M, Kawamura Y, Kajiwara H, Yoshida SI. Capsule ofStreptococcus pyogenesIs Essential for Delayed Death of Mice in a Model of Streptococcal Toxic Shock Syndrome. Microbiol Immunol 2013; 50:127-30. [PMID: 16490930 DOI: 10.1111/j.1348-0421.2006.tb03777.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have previously reported a mouse model of severe group A streptococcal infection (Microbiol. Immunol. 45: 777-786, 2001). When we injected Streptococcus pyogenes strains intramuscularly, the mice suffered from acute phase of infection for a few days but recovered from the illness and gained body weight. These mice, however, began to die after 3 weeks of infection, which we called 'delayed death.' Bacterial strains isolated from organs of the dead mice showed thick capsules. We, therefore, constructed a hyaluronic acid capsule gene, hasA, knockout mutant by homologous recombination and the effect of capsule on the death was observed. hasA knockout strain did not cause delayed death, though it caused acute death at high doses of infection. According to this result, the capsule is a critical pathogenic factor for causing the delayed death in our mouse model.
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Affiliation(s)
- Ken-ichiro Iida
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Japan.
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42
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Chen VL, Avci FY, Kasper DL. A maternal vaccine against group B Streptococcus: past, present, and future. Vaccine 2013; 31 Suppl 4:D13-9. [PMID: 23973342 PMCID: PMC3757342 DOI: 10.1016/j.vaccine.2012.12.080] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Accepted: 12/31/2012] [Indexed: 01/22/2023]
Abstract
Group B Streptococcus (GBS) is a major cause of morbidity and mortality among neonates. Though there have been tremendous advances in prevention of invasive neonatal GBS disease through prophylactic antibiotic treatment of pregnant women, the incidence of neonatal disease has not changed significantly over the past several years. Vaccination of pregnant women is an important strategy that has the potential to improve further on existing protocols. In this review, we explore the history of the design of maternal GBS vaccines. We also discuss how recent applications of genomics and immunology to vaccine design promise to further enhance our ability to develop more effective vaccines against this important disease.
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MESH Headings
- Antibodies, Bacterial/immunology
- Female
- Humans
- Infant, Newborn
- Infant, Newborn, Diseases/immunology
- Infant, Newborn, Diseases/microbiology
- Infant, Newborn, Diseases/prevention & control
- Polysaccharides, Bacterial/administration & dosage
- Polysaccharides, Bacterial/immunology
- Pregnancy
- Reproductive Tract Infections/microbiology
- Reproductive Tract Infections/transmission
- Streptococcal Infections/immunology
- Streptococcal Infections/microbiology
- Streptococcal Infections/prevention & control
- Streptococcal Vaccines/administration & dosage
- Streptococcal Vaccines/immunology
- Streptococcus agalactiae/immunology
- Vaccination
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Affiliation(s)
- Vincent L. Chen
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA; Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Fikri Y. Avci
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA; Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Dennis L. Kasper
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA; Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
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43
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Caliot É, Dramsi S, Chapot-Chartier MP, Courtin P, Kulakauskas S, Péchoux C, Trieu-Cuot P, Mistou MY. Role of the Group B antigen of Streptococcus agalactiae: a peptidoglycan-anchored polysaccharide involved in cell wall biogenesis. PLoS Pathog 2012; 8:e1002756. [PMID: 22719253 PMCID: PMC3375309 DOI: 10.1371/journal.ppat.1002756] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 05/03/2012] [Indexed: 11/18/2022] Open
Abstract
Streptococcus agalactiae (Group B streptococcus, GBS) is a leading cause of infections in neonates and an emerging pathogen in adults. The Lancefield Group B carbohydrate (GBC) is a peptidoglycan-anchored antigen that defines this species as a Group B Streptococcus. Despite earlier immunological and biochemical characterizations, the function of this abundant glycopolymer has never been addressed experimentally. Here, we inactivated the gene gbcO encoding a putative UDP-N-acetylglucosamine-1-phosphate:lipid phosphate transferase thought to catalyze the first step of GBC synthesis. Indeed, the gbcO mutant was unable to synthesize the GBC polymer, and displayed an important growth defect in vitro. Electron microscopy study of the GBC-depleted strain of S. agalactiae revealed a series of growth-related abnormalities: random placement of septa, defective cell division and separation processes, and aberrant cell morphology. Furthermore, vancomycin labeling and peptidoglycan structure analysis demonstrated that, in the absence of GBC, cells failed to initiate normal PG synthesis and cannot complete polymerization of the murein sacculus. Finally, the subcellular localization of the PG hydrolase PcsB, which has a critical role in cell division of streptococci, was altered in the gbcO mutant. Collectively, these findings show that GBC is an essential component of the cell wall of S. agalactiae whose function is reminiscent of that of conventional wall teichoic acids found in Staphylococcus aureus or Bacillus subtilis. Furthermore, our findings raise the possibility that GBC-like molecules play a major role in the growth of most if not all beta-hemolytic streptococci.
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Affiliation(s)
- Élise Caliot
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
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44
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Park JK, Choi DJ, Kim SM, Choi HN, Park JW, Jang SJ, Choo YK, Lee CG, Park YI. Purification and characterization of a polysialic acid-specific sialidase from Pseudomonas fluorescens JK-0412. BIOTECHNOL BIOPROC E 2012. [DOI: 10.1007/s12257-011-0495-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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45
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Fine specificity and cross-reactions of monoclonal antibodies to group B streptococcal capsular polysaccharide type III. Vaccine 2012; 30:4849-58. [PMID: 22634296 DOI: 10.1016/j.vaccine.2012.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 05/01/2012] [Accepted: 05/03/2012] [Indexed: 01/01/2023]
Abstract
Group B streptococcus (GBS) is a major cause of neonatal sepsis and meningitis. Despite aggressive campaigns using antenatal prophylactic antibiotic therapy, infections continue. Developing an effective maternal vaccine is a public health priority. Antibody (Ab) to the capsular polysaccharide (CPS) is considered the dominant "protective" immune mediator. Here we study the fine specificity and potential host reactivity of a panel of well-characterized murine monoclonal Abs against the type III CPS by examining the binding of the Abs to intact and neuraminidase-digested GBS, purified CPS, synthetic carbohydrate structures, and cells. The results showed marked differences in the fine specificity among these mAbs to a single carbohydrate structure. Cross-reactions with synthetic GD3 and GT3 carbohydrates, representing structures found on surfaces of neural and developing cells, were demonstrated using carbohydrate array technology. The anti-CPS(III) mAbs did not react with cells expressing GD3 and GT3, nor did mAbs specific for the host carbohydrates cross-react with GBS, raising questions about the physiological relevance of this cross-reaction. But in the process of these investigations, we serendipitously demonstrated cross-reactions of some anti-CPS(III) mAbs with antigens, likely carbohydrates, found on human leukocytes. These studies suggest caution in the development of a maternal vaccine to prevent infection by this important human pathogen.
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46
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Lecours MP, Fittipaldi N, Takamatsu D, Okura M, Segura M, Goyette-Desjardins G, Van Calsteren MR, Gottschalk M. Sialylation of Streptococcus suis serotype 2 is essential for capsule expression but is not responsible for the main capsular epitope. Microbes Infect 2012; 14:941-50. [PMID: 22521569 DOI: 10.1016/j.micinf.2012.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 02/24/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
Abstract
The capsular polysaccharide is a critical virulence factor of the swine and zoonotic pathogen Streptococcus suis serotype 2. The capsule of this bacterium is composed of five different sugars, including terminal sialic acid. To evaluate the role of sialic acid in the pathogenesis of the infection, the neuC gene, encoding for an enzyme essential for sialic acid biosynthesis, was inactivated in a highly virulent S. suis serotype 2 strain. Using transmission electron microscopy, it was shown that inactivation of neuC resulted in loss of expression of the whole capsule. Compared to the parent strain, the ΔneuC mutant strain was more phagocytosed by macrophages and was also severely impaired in virulence in a mouse infection model. Both native and desialylated S. suis serotype 2 purified capsular polysaccharides were recognized by a polyclonal anti-whole cell S. suis serotype 2 serum and a monospecific polyclonal anti-capsule serotype 2 serum. In contrast, only the native capsular polysaccharide was recognized by a monoclonal antibody specific for the sialic acid moiety of the serotype 2 capsule. Together, our results infer that sialylation of S. suis serotype 2 may be essential for capsule expression, but that this sugar is not the main epitope of this serotype.
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Affiliation(s)
- Marie-Pier Lecours
- Faculté de médecine vétérinaire, Université de Montréal, 3200 Sicotte, St-Hyacinthe, Québec, Canada J2S 2M2
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47
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Segura M. Fisher scientific award lecture - the capsular polysaccharides of Group B Streptococcus and Streptococcus suis differently modulate bacterial interactions with dendritic cells. Can J Microbiol 2012; 58:249-60. [PMID: 22356626 DOI: 10.1139/w2012-003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Infections with encapsulated bacteria cause serious clinical problems. Besides being poorly immunogenic, the bacterial capsular polysaccharide (CPS) cloaks antigenic proteins, allowing bacterial evasion of the host immune system. Despite the clinical significance of bacterial CPS and its suggested role in the pathogenesis of the infection, the mechanisms underlying innate and, critically, adaptive immune responses to encapsulated bacteria have not been fully elucidated. As such, we became interested in studying the CPS of two similar, but unique, streptococcal species: Group B Streptococcus (GBS) and Streptococcus suis . Both streptococci are well encapsulated, some capsular types are more virulent than others, and they can cause severe meningitis and septicemia. For both pathogens, the CPS is considered the major virulence factor. Finally, these two streptococci are the sole Gram-positive bacteria possessing sialic acid in their capsules. GBS type III is a leading cause of neonatal invasive infections. Streptococcus suis type 2 is an important swine and emerging zoonotic pathogen in humans. We recently characterized the S. suis type 2 CPS. It shares common structural elements with GBS, but sialic acid is α2,6-linked to galactose rather than α2,3-linked. Differential sialic acid expression by pathogens might result in modulation of immune cell activation and, consequently, may affect the immuno-pathogenesis of these bacterial infections. Here, we review and compare the interactions of these two sialylated encapsulated bacteria with dendritic cells, known as the most potent antigen-presenting cells linking innate and adaptive immunity. We further address differences between dendritic cells and professional phagocytes, such as macrophages and neutrophils, in their interplay with these encapsulated pathogens. Elucidation of the molecular and cellular basis of the impact of CPS composition on bacterial interactions with immune cells is critical for mechanistic understanding of anti-CPS responses. Knowledge generated will help to advance the development of novel, more effective anti-CPS vaccines and improved immunotherapies.
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Affiliation(s)
- Mariela Segura
- Laboratory of Immunology, Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, 3200 rue Sicotte, St-Hyacinthe, QC J2S 2M2, Canada.
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48
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Lartigue MF, Poulard AF, Al Safadi R, Pailhories H, Domelier-Valentin AS, van der Mee-Marquet N, Rosenau A, Quentin R. Variability of neuD transcription levels and capsular sialic acid expression among serotype III group B Streptococcus strains. Microbiology (Reading) 2011; 157:3282-3291. [DOI: 10.1099/mic.0.050013-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Serotype III group B Streptococcus (GBS) is the major cause of neonatal meningitis, but the risk of infection in the colonized neonates is variable. Capsular sialic acid (Sia), whose synthesis is encoded by neu genes, appears to be a major virulence factor in several bacterial species able to reach the cerebrospinal fluid. Therefore, variations of Sia expression related to the genetic diversity of strains may have an impact on the risk of meningitis in colonized neonates. We characterized by MLST the phylogenetic diversity of 64 serotype III GBS strains isolated from vaginal flora and randomly selected. These strains mostly belonged to three major sequence types (STs): ST1 (11 %), ST17 (39 %) and ST19 (31 %). The genetic diversity of strains of these lineages, characterized by PFGE, allowed the selection of 17 representative strains, three ST1, six ST17 and eight ST19, with NEM316 as reference, in order to evaluate (i) by quantitative RT-PCR, the level of transcription of the neuD gene as a marker for the transcription of neu genes and (ii) by enzymological analysis, the expression of Sia. The mean transcription level of neuD was higher for ST17 strains than for ST1 and ST19 strains in the early, mid- and late exponential growth phases, and was maximum in the early exponential growth phase for ST17 strains and in the mid-exponential growth phase for ST1 and ST19 strains. Mean Sia concentration was higher for ST17 than for ST1 and ST9 strains in all three growth phases. For the total population, Sia concentration varied notably in the stationary phase, from 0.38 to 9.30 nmol per 108 viable bacteria, with a median value of 2.99 nmol per 108 bacteria. All ST17 strains, only one-third of the ST19 strains and none of the ST1 strains had Sia concentrations higher than the median Sia concentration. Therefore, differences in the level of expression of Sia by strains of the major serotype III GBS phylogenetic lineages might be one of the factors that explain the leading role of ST17 strains in neonatal meningitis.
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Affiliation(s)
- Marie-Frédérique Lartigue
- Service de Bactériologie et Hygiène Hospitalière, Hôpital Trousseau, CHRU de Tours, 37044 Tours, France
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 ‘Bactéries et Risque Materno-foetal’, Institut Fédératif de Recherche 136 ‘Agents Transmissibles et Infectiologie’, 37032 Tours Cedex, France
| | - Agnès Fribourg Poulard
- Service de Bactériologie et Hygiène Hospitalière, Hôpital Trousseau, CHRU de Tours, 37044 Tours, France
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 ‘Bactéries et Risque Materno-foetal’, Institut Fédératif de Recherche 136 ‘Agents Transmissibles et Infectiologie’, 37032 Tours Cedex, France
| | - Rim Al Safadi
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 ‘Bactéries et Risque Materno-foetal’, Institut Fédératif de Recherche 136 ‘Agents Transmissibles et Infectiologie’, 37032 Tours Cedex, France
| | - Hélène Pailhories
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 ‘Bactéries et Risque Materno-foetal’, Institut Fédératif de Recherche 136 ‘Agents Transmissibles et Infectiologie’, 37032 Tours Cedex, France
| | - Anne-Sophie Domelier-Valentin
- Service de Bactériologie et Hygiène Hospitalière, Hôpital Trousseau, CHRU de Tours, 37044 Tours, France
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 ‘Bactéries et Risque Materno-foetal’, Institut Fédératif de Recherche 136 ‘Agents Transmissibles et Infectiologie’, 37032 Tours Cedex, France
| | - Nathalie van der Mee-Marquet
- Service de Bactériologie et Hygiène Hospitalière, Hôpital Trousseau, CHRU de Tours, 37044 Tours, France
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 ‘Bactéries et Risque Materno-foetal’, Institut Fédératif de Recherche 136 ‘Agents Transmissibles et Infectiologie’, 37032 Tours Cedex, France
| | - Agnès Rosenau
- Service de Bactériologie et Hygiène Hospitalière, Hôpital Trousseau, CHRU de Tours, 37044 Tours, France
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 ‘Bactéries et Risque Materno-foetal’, Institut Fédératif de Recherche 136 ‘Agents Transmissibles et Infectiologie’, 37032 Tours Cedex, France
| | - Roland Quentin
- Service de Bactériologie et Hygiène Hospitalière, Hôpital Trousseau, CHRU de Tours, 37044 Tours, France
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 ‘Bactéries et Risque Materno-foetal’, Institut Fédératif de Recherche 136 ‘Agents Transmissibles et Infectiologie’, 37032 Tours Cedex, France
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49
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Burnside K, Lembo A, Harrell MI, Gurney M, Xue L, BinhTran NT, Connelly JE, Jewell KA, Schmidt BZ, de Los Reyes M, Tao WA, Doran KS, Rajagopal L. Serine/threonine phosphatase Stp1 mediates post-transcriptional regulation of hemolysin, autolysis, and virulence of group B Streptococcus. J Biol Chem 2011; 286:44197-44210. [PMID: 22081606 DOI: 10.1074/jbc.m111.313486] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Elucidating how serine/threonine phosphatases regulate kinase function and bacterial virulence is critical for our ability to combat these infections. Group B streptococci (GBS) are β-hemolytic Gram-positive bacteria that cause invasive infections in humans. To adapt to environmental changes, GBS encodes signaling mechanisms comprising two component systems and eukaryotic-like enzymes. We have previously described the importance of the serine/threonine kinase Stk1 to GBS pathogenesis. However, how the presence or absence of the cognate serine/threonine phosphatase Stp1 affects Stk1 function and GBS virulence is not known. Here, we show that GBS deficient only in Stp1 expression are markedly reduced for their ability to cause systemic infections, exhibit decreased β-hemolysin/cytolysin activity, and show increased sensitivity to autolysis. Although transcription of genes important for β-hemolysin/cytolysin expression and export is similar to the wild type (WT), 294 genes (excluding stp1) showed altered expression in the stp1 mutant and included autolysin genes. Furthermore, phosphopeptide enrichment analysis identified that 35 serine/threonine phosphopeptides, corresponding to 27 proteins, were unique to the stp1 mutant. This included phosphorylation of ATP synthase, DNA and RNA helicases, and proteins important for cell division and protein synthesis. Collectively, our results indicate that Stp1 is important for appropriate regulation of Stk1 function, hemolysin activity, autolysis, and GBS virulence.
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Affiliation(s)
- Kellie Burnside
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Annalisa Lembo
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Maria Isabel Harrell
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Michael Gurney
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California 92182
| | - Liang Xue
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Nguyen-Thao BinhTran
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - James E Connelly
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Kelsea A Jewell
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Byron Z Schmidt
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Melissa de Los Reyes
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Weiguo Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Kelly S Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California 92182
| | - Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101.
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50
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NeuA O-acetylesterase activity is specific for CMP-activated O-acetyl sialic acid in Streptococcus suis serotype 2. Biochem Biophys Res Commun 2011; 410:212-7. [DOI: 10.1016/j.bbrc.2011.05.092] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 05/15/2011] [Indexed: 11/17/2022]
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