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Rajack F, Medford S, Ramadan A, Naab T. Emerging infection: streptococcal toxic shock-like syndrome caused by group B Streptococcus (GBS), Streptococcus agalactiae. Autops Case Rep 2024; 14:e2024497. [PMID: 39021470 PMCID: PMC11253910 DOI: 10.4322/acr.2024.497] [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: 09/26/2023] [Accepted: 04/25/2024] [Indexed: 07/20/2024]
Abstract
Streptococcus agalactiae or Group B Streptococcus (GBS) infections are commonly associated with infections in neonates and pregnant women. However, there has been a rising incidence in nonpregnant adults. The risk of GBS infection in nonpregnant adults is increased for patients of advanced age and those with underlying medical conditions such as diabetes mellitus and cancer. We present a 77-year-old female with type-2 diabetes mellitus, hypertension, and bilateral foot ulcers that presented in probable septic shock with necrotic foot ulcers and necrotizing fasciitis and underwent bilateral lower limb amputations. The patient fulfilled the Streptococcal Toxic Shock Syndrome (STSS) criteria as defined by The Working Group on Severe Streptococcal Infections. These criteria were created for group A Streptococcus (Streptococcus pyogenes). Our patient fulfilled the Working Group's criteria, except that the blood culture was positive for group B Streptococcus (Streptococcus agalactiae). Numerous studies demonstrate the importance of early detection and antibiotic treatment for GBS infections in general and early surgical management for necrotizing soft tissue infections (NSTIs) such as necrotizing fasciitis.
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Affiliation(s)
- Fareed Rajack
- Howard University Hospital, Department of Pathology and Laboratory Medicine, Washington, D.C., United States of America
| | - Shawn Medford
- Howard University College of Medicine, Washington, D.C., United States of America
| | - Ali Ramadan
- Howard University Hospital, Department of Pathology and Laboratory Medicine, Washington, D.C., United States of America
| | - Tammey Naab
- Howard University Hospital, Department of Pathology and Laboratory Medicine, Washington, D.C., United States of America
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Bousbaine D, Bauman KD, Chen YE, Yu VK, Lalgudi PV, Naziripour A, Veinbachs A, Phung JL, Nguyen TTD, Swenson JM, Lee YE, Dimas A, Jain S, Meng X, Pham TPT, Zhao A, Barkal L, Gribonika I, Van Rompay KKA, Belkaid Y, Barnes CO, Fischbach MA. Discovery and engineering of the antibody response against a prominent skin commensal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576900. [PMID: 38328052 PMCID: PMC10849572 DOI: 10.1101/2024.01.23.576900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The ubiquitous skin colonist Staphylococcus epidermidis elicits a CD8 + T cell response pre-emptively, in the absence of an infection 1 . However, the scope and purpose of this anti-commensal immune program are not well defined, limiting our ability to harness it therapeutically. Here, we show that this colonist also induces a potent, durable, and specific antibody response that is conserved in humans and non-human primates. A series of S. epidermidis cell-wall mutants revealed that the cell surface protein Aap is a predominant target. By colonizing mice with a strain of S. epidermidis in which the parallel β-helix domain of Aap is replaced by tetanus toxin fragment C, we elicit a potent neutralizing antibody response that protects mice against a lethal challenge. A similar strain of S. epidermidis expressing an Aap-SpyCatcher chimera can be conjugated with recombinant immunogens; the resulting labeled commensal elicits high titers of antibody under conditions of physiologic colonization, including a robust IgA response in the nasal mucosa. Thus, immunity to a common skin colonist involves a coordinated T and B cell response, the latter of which can be redirected against pathogens as a novel form of topical vaccination.
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3
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Palit S, Bhide AJ, Mohanasundaram B, Pala M, Banerjee AK. Peptides from conserved tandem direct repeats of SHORT-LEAF regulate gametophore development in moss P. patens. PLANT PHYSIOLOGY 2023; 194:434-455. [PMID: 37770073 DOI: 10.1093/plphys/kiad515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 10/03/2023]
Abstract
Tandem direct repeat (TDR)-containing proteins, present across all domains of life, play crucial roles in plant development and defense mechanisms. Previously, we identified that disruption of a bryophyte-specific protein family, SHORT-LEAF (SHLF), possessing the longest reported TDRs, is the cause of the shlf mutant phenotype in Physcomitrium patens. shlf exhibits reduced apical dominance, altered auxin distribution, and 2-fold shorter leaves. However, the molecular role of SHLF was unclear due to the absence of known conserved domains. Through a series of protein domain deletion analyses, here, we demonstrate the importance of the signal peptide and the conserved TDRs and report a minimal functional protein (miniSHLF) containing the N-terminal signal peptide and first two TDRs (N-TDR1-2). We also demonstrate that SHLF behaves as a secretory protein and that the TDRs contribute to a pool of secreted peptides essential for SHLF function. Further, we identified that the mutant secretome lacks SHLF peptides, which are abundant in WT and miniSHLF secretomes. Interestingly, shlf mutants supplemented with the secretome or peptidome from WT or miniSHLF showed complete or partial phenotypic recovery. Transcriptomic and metabolomic analyses revealed that shlf displays an elevated stress response, including high ROS activity and differential accumulation of genes and metabolites involved in the phenylpropanoid pathway, which may affect auxin distribution. The TDR-specific synthetic peptide SHLFpep3 (INIINAPLQGFKIA) also rescued the mutant phenotypes, including the altered auxin distribution, in a dosage-dependent manner and restored the mutant's stress levels. Our study shows that secretory SHLF peptides derived from conserved TDRs regulate moss gametophore development.
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Affiliation(s)
- Shirsa Palit
- Department of Biology, Indian Institute of Science Education and Research (IISER-Pune), Dr. Homi Bhabha Road, Maharashtra, Pune 411008, India
| | - Amey J Bhide
- Department of Biology, Indian Institute of Science Education and Research (IISER-Pune), Dr. Homi Bhabha Road, Maharashtra, Pune 411008, India
| | | | - Madhusmita Pala
- Department of Biology, Indian Institute of Science Education and Research (IISER-Pune), Dr. Homi Bhabha Road, Maharashtra, Pune 411008, India
| | - Anjan K Banerjee
- Department of Biology, Indian Institute of Science Education and Research (IISER-Pune), Dr. Homi Bhabha Road, Maharashtra, Pune 411008, India
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4
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A novel strategy for designing the antioxidant and adhesive bifunctional protein using the Lactobacillus strain-derived LPxTG motif structure. Process Biochem 2023. [DOI: 10.1016/j.procbio.2023.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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5
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Structural Identification of Lipid-α: A Glycosyl Lipid Involved in Oligo- And Polysaccharides Metabolism in Streptococcus agalactiae (Group B Streptococcus). Curr Microbiol 2022; 80:16. [PMID: 36459236 DOI: 10.1007/s00284-022-03117-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 11/09/2022] [Indexed: 12/04/2022]
Abstract
Streptococcus agalactiae (group B Streptococcus, GBS) is a gram-positive bacterium that is an asymptomatic colonizer commonly found in the gastrointestinal and genitourinary tract of healthy adults. GBS is also the most common cause of life-threatening bacterial infections in newborns and is emerging as a pathogen in immunocompromised and diabetic adults. The GBS cell wall and covalently linked capsular polysaccharides (CPS) are vital to the protection of the bacterial cell and act as virulence factors. GBS-CPS have been successfully used to produce conjugate vaccines for all currently identified GBS serotypes. However, the mechanisms of biosynthesis and assembly of CPS and the other cell wall components remain poorly defined due to their complex surface structures. In this biosynthetic study of the GBS cell wall-CPS complex, glycolipids with varying lengths of glycosyl-chains were discovered. Among those, one of the smallest glycolipids (named GBS Lipid-α) was structurally characterized. Lipid-α is involved in GBS saccharide metabolism and presumably acts as a glycosyl acceptor to elongate the glycosyl chain. GBS Lipid-α was determined to be a 3-monosaccharide 1,2 acyl glycerol with a molecular mass in the range of m/z = 724-808. GBS Lipid-α is highly heterogenic with various acyl groups and glycosyl moieties. This knowledge will pave the way for future studies to elucidate the entire metabolic pathway and genes involved. The Lipid-α pathway may also exist in other bacterial species and has the potential to be a biomarker for future drug development.
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6
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Govindarajan DK, Kandaswamy K. Virulence factors of uropathogens and their role in host pathogen interactions. Cell Surf 2022; 8:100075. [PMID: 35198842 PMCID: PMC8841375 DOI: 10.1016/j.tcsw.2022.100075] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 02/01/2022] [Accepted: 02/06/2022] [Indexed: 12/26/2022] Open
Abstract
Gram-positive and Gram-negative bacterial pathogens are commonly found in Urinary Tract Infection (UTI), particularly infected in females like pregnant women, elder people, sexually active, or individuals prone to other risk factors for UTI. In this article, we review the expression of virulence surface proteins and their interaction with host cells for the most frequently isolated uropathogens: Escherichia coli, Enterococcus faecalis, Proteus mirabilis, Klebsiella pneumoniae, and Staphylococcus saprophyticus. In addition to the host cell interaction, surface protein regulation was also discussed in this article. The surface protein regulation serves as a key tool in differentiating the pathogen isotypes. Furthermore, it might provide insights on novel diagnostic methods to detect uropathogen that are otherwise easily overlooked due to limited culture-based assays. In essence, this review shall provide an in-depth understanding on secretion of virulence factors of various uropathogens and their role in host-pathogen interaction, this knowledge might be useful in the development of therapeutics against uropathogens.
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Affiliation(s)
| | - Kumaravel Kandaswamy
- Corresponding author at: Department of Biotechnology, Kumaraguru College of Technology (KCT), Chinnavedampatti, Coimbatore 641049, Tamil Nadu, India.
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7
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The long and the short of Periscope Proteins. Biochem Soc Trans 2022; 50:1293-1302. [PMID: 36196877 DOI: 10.1042/bst20220194] [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: 07/26/2022] [Revised: 09/10/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022]
Abstract
Bacteria sense, interact with, and modify their environmental niche by deploying a molecular ensemble at the cell surface. The changeability of this exposed interface, combined with extreme changes in the functional repertoire associated with lifestyle switches from planktonic to adherent and biofilm states necessitate dynamic variability. Dynamic surface changes include chemical modifications to the cell wall; export of diverse extracellular biofilm components; and modulation of expression of cell surface proteins for adhesion, co-aggregation and virulence. Local enrichment for highly repetitive proteins with high tandem repeat identity has been an enigmatic phenomenon observed in diverse bacterial species. Preliminary observations over decades of research suggested these repeat regions were hypervariable, as highly related strains appeared to express homologues with diverse molecular mass. Long-read sequencing data have been interrogated to reveal variation in repeat number; in combination with structural, biophysical and molecular dynamics approaches, the Periscope Protein class has been defined for cell surface attached proteins that dynamically expand and contract tandem repeat tracts at the population level. Here, I review the diverse high-stability protein folds and coherent interdomain linkages culminating in the formation of highly anisotropic linear repeat arrays, so-called rod-like protein 'stalks', supporting roles in bacterial adhesion, biofilm formation, cell surface spatial competition, and immune system modulation. An understanding of the functional impacts of dynamic changes in repeat arrays and broader characterisation of the unusual protein folds underpinning this variability will help with the design of immunisation strategies, and contribute to synthetic biology approaches including protein engineering and microbial consortia construction.
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8
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Sulovari A, Ninomiya MJ, Beck CA, Ricciardi BF, Ketonis C, Mesfin A, Kaplan NB, Soin SP, McDowell SM, Mahmood B, Daiss JL, Schwarz EM, Oh I. Clinical utilization of species-specific immunoassays for identification of Staphylococcus aureus and Streptococcus agalactiae in orthopedic infections. J Orthop Res 2021; 39:2141-2150. [PMID: 33274775 PMCID: PMC8175449 DOI: 10.1002/jor.24935] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 11/09/2020] [Accepted: 12/01/2020] [Indexed: 02/04/2023]
Abstract
Staphylococcus aureus and Streptococcus agalactiae (Group B streptococcus, GBS) are common causes of deep musculoskeletal infections (MSKI) and result in significant patient morbidity and cost to the healthcare system. One of the major challenges with MSKI is the lack of faithful diagnostics to correctly identify the primary pathogen, as standard culture-based assays are prone to false positives in the case of polymicrobial infections, and false negatives due to limitations in sample acquisition and antibiotic use before presentation. To improve upon our current diagnostic methods for MSKI, we developed a multiplex immunoassay for antigen-specific IgGs in serum (Luminex), and medium enriched for newly synthesized antibodies (MENSA) for anti-S. aureus and GBS generated from cultured peripheral blood mononuclear cells (PBMCs) of orthopedic infection patients undergoing surgical treatment. Samples were obtained from 110 MSKI patients: 80 diabetic foot ulcer, 21 periprosthetic joint infection, 5 septic arthritis, 2 spine, 1 hand, and 1 fracture-related infection (FRI). Anti-S. aureus and anti-GBS antibody titers were compared to culture results to assess their concordance in identifying the pathogens. Immunoassay, particularly MENSA, showed high diagnostic potential for monomicrobial S. aureus and GBS orthopedic infections (AUC > 0.95). MENSA also demonstrated diagnostic potential for GBS polymicrobial orthopedic infection and for GBS DFU (AUC > 0.83 for both). Serum showed high diagnostic potential for S. aureus PJI (AUC > 0.95). Taken together, these findings support the development of species-specific immunoassays for the identification of causal pathogens in active MSKI, especially in conjunction with standard culture.
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Affiliation(s)
- Aron Sulovari
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Mark J. Ninomiya
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Christopher A. Beck
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Benjamin F. Ricciardi
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Constantinos Ketonis
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Addisu Mesfin
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Nathan B. Kaplan
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Sandeep P. Soin
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Susan M. McDowell
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Bilal Mahmood
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - John L. Daiss
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
| | - Edward M. Schwarz
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Biomedical Engineering, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
- Department of Microbiology & Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Irvin Oh
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, USA
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9
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Berardi A, Trevisani V, Di Caprio A, Bua J, China M, Perrone B, Pagano R, Lucaccioni L, Fanaro S, Iughetti L, Lugli L, Creti R. Understanding Factors in Group B Streptococcus Late-Onset Disease. Infect Drug Resist 2021; 14:3207-3218. [PMID: 34429620 PMCID: PMC8380284 DOI: 10.2147/idr.s291511] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/14/2021] [Indexed: 12/22/2022] Open
Abstract
Group B streptococcus (GBS) infection remains a leading cause of sepsis, pneumonia, and meningitis in infants. Rates of GBS early onset disease have declined following the widcespread use of intrapartum antibiotic prophylaxis; hence, late-onset infections (LOGBS) are currently a common presentation of neonatal GBS dicsease. The pathogenesis, mode of transmission, and risk factors associated with LOGBS are unclear, which interfere with effective prevention efforts. GBS may be transmitted from the mother to the infant at the time of delivery or during the postpartum period via contaminated breast milk, or as nosocomial or community-acquired infection. Maternal GBS colonization, prematurity, young maternal age, HIV exposure, and ethnicity (Black) are identified as risk factors for LOGBS disease; however, further studies are necessary to confirm additional risk factors, if any, for the implementation of effective prevention strategies. This narrative review discusses current and previous studies that have reported LOGBS. Few well-designed studies have described this condition; therefore, reliable assessment of maternal GBS colonization, breastfeeding, and twin delivery as risk factors for LOGBS remains limited.
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Affiliation(s)
- Alberto Berardi
- Terapia Intensiva Neonatale, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy
| | - Viola Trevisani
- Scuola di Specializzazione in Pediatria, Università di Modena & Reggio Emilia, Modena, Italy
| | - Antonella Di Caprio
- Scuola di Specializzazione in Pediatria, Università di Modena & Reggio Emilia, Modena, Italy
| | - Jenny Bua
- Terapia Intensiva Neonatale, IRCCS Azienda Ospedaliero Universitaria "Burlo Garofalo", Trieste, Italy
| | | | - Barbara Perrone
- Terapia Intensiva Neonatale, Azienda Ospedaliero Universitaria Ospedali Riuniti, Ancona, Italy
| | - Rossella Pagano
- Unità Operativa di Pediatria, Civile Sassuolo, Sassuolo, Italy
| | - Laura Lucaccioni
- Unità Operativa di Pediatria, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy
| | - Silvia Fanaro
- Terapia Intensiva Neonatale, Azienda Ospedaliero-Universitaria S. Anna, Ferrara, Italy
| | - Lorenzo Iughetti
- Scuola di Specializzazione in Pediatria, Università di Modena & Reggio Emilia, Modena, Italy.,Unità Operativa di Pediatria, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy
| | - Licia Lugli
- Terapia Intensiva Neonatale, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy
| | - Roberta Creti
- Reparto di Antibiotico Resistenza e Patogeni Speciali (AR-PS), Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
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10
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Asare P, Asante-Poku A, Osei-Wusu S, Otchere ID, Yeboah-Manu D. The Relevance of Genomic Epidemiology for Control of Tuberculosis in West Africa. Front Public Health 2021; 9:706651. [PMID: 34368069 PMCID: PMC8342769 DOI: 10.3389/fpubh.2021.706651] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/29/2021] [Indexed: 12/30/2022] Open
Abstract
Tuberculosis (TB), an airborne infectious disease caused by Mycobacterium tuberculosis complex (MTBC), remains a global health problem. West Africa has a unique epidemiology of TB that is characterized by medium- to high-prevalence. Moreover, the geographical restriction of M. africanum to the sub-region makes West Africa have an extra burden to deal with a two-in-one pathogen. The region is also burdened with low case detection, late reporting, poor treatment adherence leading to development of drug resistance and relapse. Sporadic studies conducted within the subregion report higher burden of drug resistant TB (DRTB) than previously thought. The need for more sensitive and robust tools for routine surveillance as well as to understand the mechanisms of DRTB and transmission dynamics for the design of effective control tools, cannot be overemphasized. The advancement in molecular biology tools including traditional fingerprinting and next generation sequencing (NGS) technologies offer reliable tools for genomic epidemiology. Genomic epidemiology provides in-depth insight of the nature of pathogens, circulating strains and their spread as well as prompt detection of the emergence of new strains. It also offers the opportunity to monitor treatment and evaluate interventions. Furthermore, genomic epidemiology can be used to understand potential emergence and spread of drug resistant strains and resistance mechanisms allowing the design of simple but rapid tools. In this review, we will describe the local epidemiology of MTBC, highlight past and current investigations toward understanding their biology and spread as well as discuss the relevance of genomic epidemiology studies to TB control in West Africa.
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Affiliation(s)
- Prince Asare
- College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Adwoa Asante-Poku
- College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Stephen Osei-Wusu
- College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Isaac Darko Otchere
- College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Dorothy Yeboah-Manu
- College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
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11
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Periscope Proteins are variable-length regulators of bacterial cell surface interactions. Proc Natl Acad Sci U S A 2021; 118:2101349118. [PMID: 34074781 PMCID: PMC8201768 DOI: 10.1073/pnas.2101349118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The structure of single and tandem SHIRT domains from the streptococcal surface protein Sgo_0707 were determined. In conjunction with biophysics and molecular dynamics simulations, the results show that the observed gene length variation would result in differential projection of the host ligand binding domain on the bacterial cell surface. An analysis of long-read DNA sequence data reveals many other repetitive bacterial surface proteins that appear to undergo gene length variation. We propose that these variable-length “Periscope Proteins” represent an important mechanism of bacterial cell surface modification with potential roles in infection and immune evasion. Changes at the cell surface enable bacteria to survive in dynamic environments, such as diverse niches of the human host. Here, we reveal “Periscope Proteins” as a widespread mechanism of bacterial surface alteration mediated through protein length variation. Tandem arrays of highly similar folded domains can form an elongated rod-like structure; thus, variation in the number of domains determines how far an N-terminal host ligand binding domain projects from the cell surface. Supported by newly available long-read genome sequencing data, we propose that this class could contain over 50 distinct proteins, including those implicated in host colonization and biofilm formation by human pathogens. In large multidomain proteins, sequence divergence between adjacent domains appears to reduce interdomain misfolding. Periscope Proteins break this “rule,” suggesting that their length variability plays an important role in regulating bacterial interactions with host surfaces, other bacteria, and the immune system.
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12
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Humphries RM. Group B Streptococcus Dynamics in the United States. Clin Infect Dis 2021; 72:1014-1015. [PMID: 32060524 DOI: 10.1093/cid/ciaa155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 02/13/2020] [Indexed: 11/14/2022] Open
Affiliation(s)
- Romney M Humphries
- Accelerate Diagnostics, Tucson, Arizona, USA.,Department of Pathology, University of Arizona, Tucson, Arizona, USA
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13
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Hamada S, Nakajima M, Kaszynski RH, Kumazawa R, Matui H, Fushimi K, Goto H, Yamaguchi Y, Yasunaga H. In-hospital mortality among patients with invasive non-group A β-hemolytic Streptococcus treated with clindamycin combination therapy: a nationwide cohort study. Acute Med Surg 2021; 8:e634. [PMID: 33659065 PMCID: PMC7893999 DOI: 10.1002/ams2.634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/17/2021] [Accepted: 01/21/2021] [Indexed: 11/08/2022] Open
Abstract
Aim Combination treatment with clindamycin is recommended in patients with invasive group A Streptococcus infection; however, whether the same treatment is effective in invasive group B Streptococcus and S. dysgalactiae subspecies equisimilis infections remains unknown. We aimed to investigate whether clindamycin added to standard of care therapy would be effective in patients with invasive non-group A β-hemolytic Streptococcus infections. Methods This was a nationwide retrospective cohort study using the Japanese Diagnosis Procedure Combination inpatient database focusing on the period between 2010 and 2018. We extracted data on patients diagnosed with sepsis due to non-group A β-hemolytic Streptococcus. One-to-four propensity score-matching was undertaken to compare patients who were treated with clindamycin within 2 days of admission (clindamycin group) and those who did not (control group). The primary outcome was in-hospital mortality. Results We identified 3754 eligible patients during the study period. The patients were divided into the clindamycin (n = 296) and control groups (n = 3458). After one-to-four propensity score matching, we compared 289 and 1156 patients with and without clindamycin, respectively. In-hospital mortality did not significantly differ between the two groups (9.7% versus 10.3%; risk difference 0.3%; 95% confidence interval, -3.5% to 4.2%). Conclusions This nationwide database study showed that combination therapy involving the use of clindamycin was not associated with lower in-hospital mortality in patients with invasive non-group A β-hemolytic Streptococcus.
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Affiliation(s)
- Shoichiro Hamada
- Emergency and Critical Care Center Tokyo Metropolitan Hiroo Hospital Tokyo Japan.,Department of Trauma and Critical Care medicine School of Medicine Kyorin University Tokyo Japan
| | - Mikio Nakajima
- Emergency and Critical Care Center Tokyo Metropolitan Hiroo Hospital Tokyo Japan.,Department of Trauma and Critical Care medicine School of Medicine Kyorin University Tokyo Japan.,Department of Clinical Epidemiology and Health Economics School of Public Health The University of Tokyo Tokyo Japan
| | - Richard H Kaszynski
- Emergency and Critical Care Center Tokyo Metropolitan Hiroo Hospital Tokyo Japan
| | - Ryosuke Kumazawa
- Department of Clinical Epidemiology and Health Economics School of Public Health The University of Tokyo Tokyo Japan
| | - Hiroki Matui
- Department of Clinical Epidemiology and Health Economics School of Public Health The University of Tokyo Tokyo Japan
| | - Kiyohide Fushimi
- Department of Health Policy and Informatics Tokyo Medical and Dental University Graduate School of Medicine Tokyo Japan
| | - Hideaki Goto
- Emergency and Critical Care Center Tokyo Metropolitan Hiroo Hospital Tokyo Japan
| | - Yoshihiro Yamaguchi
- Department of Trauma and Critical Care medicine School of Medicine Kyorin University Tokyo Japan
| | - Hideo Yasunaga
- Department of Clinical Epidemiology and Health Economics School of Public Health The University of Tokyo Tokyo Japan
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Seepersaud R, Anderson AC, Bensing BA, Choudhury BP, Clarke AJ, Sullam PM. O-acetylation controls the glycosylation of bacterial serine-rich repeat glycoproteins. J Biol Chem 2021; 296:100249. [PMID: 33384382 PMCID: PMC7948813 DOI: 10.1074/jbc.ra120.016116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 12/21/2020] [Accepted: 12/31/2020] [Indexed: 01/14/2023] Open
Abstract
The serine-rich repeat (SRR) glycoproteins of gram-positive bacteria are a family of adhesins that bind to a wide range of host ligands, and expression of SRR glycoproteins is linked with enhanced bacterial virulence. The biogenesis of these surface glycoproteins involves their intracellular glycosylation and export via the accessory Sec system. Although all accessory Sec components are required for SRR glycoprotein export, Asp2 of Streptococcus gordonii also functions as an O-acetyltransferase that modifies GlcNAc residues on the SRR adhesin gordonii surface protein B (GspB). Because these GlcNAc residues can also be modified by the glycosyltransferases Nss and Gly, it has been unclear whether the post-translational modification of GspB is coordinated. We now report that acetylation modulates the glycosylation of exported GspB. Loss of O-acetylation due to aps2 mutagenesis led to the export of GspB glycoforms with increased glucosylation of the GlcNAc moieties. Linkage analysis of the GspB glycan revealed that both O-acetylation and glucosylation occurred at the same C6 position on GlcNAc residues and that O-acetylation prevented Glc deposition. Whereas streptococci expressing nonacetylated GspB with increased glucosylation were significantly reduced in their ability to bind human platelets in vitro, deletion of the glycosyltransferases nss and gly in the asp2 mutant restored platelet binding to WT levels. These findings demonstrate that GlcNAc O-acetylation controls GspB glycosylation, such that binding via this adhesin is optimized. Moreover, because O-acetylation has comparable effects on the glycosylation of other SRR adhesins, acetylation may represent a conserved regulatory mechanism for the post-translational modification of the SRR glycoprotein family.
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Affiliation(s)
- Ravin Seepersaud
- Department of Medicine, Division of Infectious Diseases, San Francisco Veteran Affairs Medical Center, and the Department of Medicine, University of California, San Francisco, California, USA
| | - Alexander C Anderson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Barbara A Bensing
- Department of Medicine, Division of Infectious Diseases, San Francisco Veteran Affairs Medical Center, and the Department of Medicine, University of California, San Francisco, California, USA
| | - Biswa P Choudhury
- GlycoAnalytics Core, University of California, San Diego, San Diego, California, USA
| | - Anthony J Clarke
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Paul M Sullam
- Department of Medicine, Division of Infectious Diseases, San Francisco Veteran Affairs Medical Center, and the Department of Medicine, University of California, San Francisco, California, USA.
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Subdominance in Antibody Responses: Implications for Vaccine Development. Microbiol Mol Biol Rev 2020; 85:85/1/e00078-20. [PMID: 33239435 DOI: 10.1128/mmbr.00078-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Vaccines work primarily by eliciting antibodies, even when recovery from natural infection depends on cellular immunity. Large efforts have therefore been made to identify microbial antigens that elicit protective antibodies, but these endeavors have encountered major difficulties, as witnessed by the lack of vaccines against many pathogens. This review summarizes accumulating evidence that subdominant protein regions, i.e., surface-exposed regions that elicit relatively weak antibody responses, are of particular interest for vaccine development. This concept may seem counterintuitive, but subdominance may represent an immune evasion mechanism, implying that the corresponding region potentially is a key target for protective immunity. Following a presentation of the concepts of immunodominance and subdominance, the review will present work on subdominant regions in several major human pathogens: the protozoan Plasmodium falciparum, two species of pathogenic streptococci, and the dengue and influenza viruses. Later sections are devoted to the molecular basis of subdominance, its potential role in immune evasion, and general implications for vaccine development. Special emphasis will be placed on the fact that a whole surface-exposed protein domain can be subdominant, as demonstrated for all of the pathogens described here. Overall, the available data indicate that subdominant protein regions are of much interest for vaccine development, not least in bacterial and protozoal systems, for which antibody subdominance remains largely unexplored.
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Zhang Z, Li Y, Hu M, Yu A. Genome reanalysis to decipher resistome, virulome, and attenuated characters of attenuated Streptococcus agalactiae strain HZAUSC001. Microb Pathog 2020; 147:104416. [PMID: 32745666 DOI: 10.1016/j.micpath.2020.104416] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/11/2020] [Accepted: 07/20/2020] [Indexed: 10/23/2022]
Abstract
Streptococcus agalactiae is a serious pathogen causing severe anthropozoonosis in a broad range of hosts, from aquatic animals to mammals, including humans. S. agalactiae HZAUSC001 was isolated from a moribund tilapia fish exhibiting classic clinical symptoms of streptococcosis in Zhanjiang, Guangdong, China. And it was identified as the etiological factor resulting in fish disease, but was notable because it exhibited attenuated virulence. Here, the genome of S. agalactiae HZAUSC001 was re-analyzed; we assessed the resistome and virulome and deciphered the attenuated characters of HZAUSC001. The S. agalactiae HZAUSC001 genome was assembled into one chromosome with a GC-content of 35.37% and 1972 predicted open reading frames (ORFs). Phylogenetic analysis indicated that it is evolutionarily similar to piscine GBS strains GD201008-001 and ZQ0910. After re-analyzing the published genomic sequence of HZAUSC001, we identified 38 virulence factor genes and one antibiotic-resistance gene. Note that three previously noted virulence genes, bca (C protein alpha-antigen), cpbA (choline-binding protein A) and esp (enterococcal surface protein), were absent in the virulence-attenuated strain S. agalactiae HZAUSC001 but present in the highly virulent strain S. agalactiae GD201008-001. We speculate that the absence of these three virulence genes may be associated with the attenuated traits of the HZAUSC001 strain. Collectively, our study supports that HZAUSC001 may be an excellent candidate for development of an attenuated vaccine, and our results contribute to further understanding of GBS epidemiology and surveillance targets.
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Affiliation(s)
- Ze Zhang
- College of Life Sciences, Beijing Normal University, Beijing, 100875, China; National Institute of Biological Sciences, Zhongguancun Life Science Park, Changping, 102206, Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, 102206, Beijing, China.
| | - Yuhui Li
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Minqiang Hu
- School of Chemical Biology and Biotechnology, Shenzhen Graduate School, Peking University, Shenzhen, 518055, China
| | - Angen Yu
- Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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17
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Eraso JM, Kachroo P, Olsen RJ, Beres SB, Zhu L, Badu T, Shannon S, Cantu CC, Saavedra MO, Kubiak SL, Porter AR, DeLeo FR, Musser JM. Genetic heterogeneity of the Spy1336/R28-Spy1337 virulence axis in Streptococcus pyogenes and effect on gene transcript levels and pathogenesis. PLoS One 2020; 15:e0229064. [PMID: 32214338 PMCID: PMC7098570 DOI: 10.1371/journal.pone.0229064] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/28/2020] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pyogenes is a strict human pathogen responsible for more than 700 million infections annually worldwide. Strains of serotype M28 S. pyogenes are typically among the five more abundant types causing invasive infections and pharyngitis in adults and children. Type M28 strains also have an unusual propensity to cause puerperal sepsis and neonatal disease. We recently discovered that a one-nucleotide indel in an intergenic homopolymeric tract located between genes Spy1336/R28 and Spy1337 altered virulence in a mouse model of infection. In the present study, we analyzed size variation in this homopolymeric tract and determined the extent of heterogeneity in the number of tandemly-repeated 79-amino acid domains in the coding region of Spy1336/R28 in large samples of strains recovered from humans with invasive infections. Both repeat sequence elements are highly polymorphic in natural populations of M28 strains. Variation in the homopolymeric tract results in (i) changes in transcript levels of Spy1336/R28 and Spy1337 in vitro, (ii) differences in virulence in a mouse model of necrotizing myositis, and (iii) global transcriptome changes as shown by RNAseq analysis of isogenic mutant strains. Variation in the number of tandem repeats in the coding sequence of Spy1336/R28 is responsible for size variation of R28 protein in natural populations. Isogenic mutant strains in which genes encoding R28 or transcriptional regulator Spy1337 are inactivated are significantly less virulent in a nonhuman primate model of necrotizing myositis. Our findings provide impetus for additional studies addressing the role of R28 and Spy1337 variation in pathogen-host interactions.
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Affiliation(s)
- Jesus M. Eraso
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Priyanka Kachroo
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Randall J. Olsen
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
- Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America
| | - Stephen B. Beres
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Luchang Zhu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Traci Badu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Sydney Shannon
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Concepcion C. Cantu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Matthew Ojeda Saavedra
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Samantha L. Kubiak
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Adeline R. Porter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Frank R. DeLeo
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - James M. Musser
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
- Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America
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18
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Whelan F, Lafita A, Griffiths SC, Cooper REM, Whittingham JL, Turkenburg JP, Manfield IW, St. John AN, Paci E, Bateman A, Potts JR. Defining the remarkable structural malleability of a bacterial surface protein Rib domain implicated in infection. Proc Natl Acad Sci U S A 2019; 116:26540-26548. [PMID: 31818940 PMCID: PMC6936399 DOI: 10.1073/pnas.1911776116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Streptococcus groups A and B cause serious infections, including early onset sepsis and meningitis in newborns. Rib domain-containing surface proteins are found associated with invasive strains and elicit protective immunity in animal models. Yet, despite their apparent importance in infection, the structure of the Rib domain was previously unknown. Structures of single Rib domains of differing length reveal a rare case of domain atrophy through deletion of 2 core antiparallel strands, resulting in the loss of an entire sheet of the β-sandwich from an immunoglobulin-like fold. Previously, observed variation in the number of Rib domains within these bacterial cell wall-attached proteins has been suggested as a mechanism of immune evasion. Here, the structure of tandem domains, combined with molecular dynamics simulations and small angle X-ray scattering, suggests that variability in Rib domain number would result in differential projection of an N-terminal host-colonization domain from the bacterial surface. The identification of 2 further structures where the typical B-D-E immunoglobulin β-sheet is replaced with an α-helix further confirms the extensive structural malleability of the Rib domain.
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Affiliation(s)
- Fiona Whelan
- Department of Biology, The University of York, YO10 5DD York, United Kingdom
| | - Aleix Lafita
- European Molecular Biology Laboratory, European Bioinformatics Institute, CB10 1SD Hinxton, United Kingdom
| | - Samuel C. Griffiths
- Department of Biology, The University of York, YO10 5DD York, United Kingdom
| | | | - Jean L. Whittingham
- York Structural Biology Laboratory, Department of Chemistry, The University of York, YO10 5DD York, United Kingdom
| | - Johan P. Turkenburg
- York Structural Biology Laboratory, Department of Chemistry, The University of York, YO10 5DD York, United Kingdom
| | - Iain W. Manfield
- Astbury Centre for Structural Molecular Biology, The University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Alexander N. St. John
- Astbury Centre for Structural Molecular Biology, The University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Emanuele Paci
- Astbury Centre for Structural Molecular Biology, The University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Alex Bateman
- European Molecular Biology Laboratory, European Bioinformatics Institute, CB10 1SD Hinxton, United Kingdom
| | - Jennifer R. Potts
- Department of Biology, The University of York, YO10 5DD York, United Kingdom
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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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Creti R, Baldassarri L, Montanaro L, Arciola C. The Alpha-Like Surface Proteins: An Example of an Expanding Family of Adhesins. Int J Artif Organs 2018; 31:834-40. [DOI: 10.1177/039139880803100912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Alpha-like protein (Alp) family, repeat-containing surface proteins once thought to be important adhesion factors confined to pathogenic streptococci and enterococci, is broader than previously known. Analysis of the annotated microbial genomes has identified new potential members of the Alp family not only in other Gram- positive opportunistic pathogens but also in commensal microflora of the human gut and the skin. This finding has highlighted the importance of genome sequencing projects for unraveling in greater detail lateral gene transfer events involving virulence factors between pathogens and commensals. These should receive constant attention not only as part of infectious disease prevention programs, but also in the food and biotechnology industries. (Int J Artif Organs 2008; 31: 834–40)
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Affiliation(s)
- R. Creti
- Department of Infectious, Parasitic and Immunomediated Diseases, National Health Institute, Rome - Italy
| | - L. Baldassarri
- Department of Infectious, Parasitic and Immunomediated Diseases, National Health Institute, Rome - Italy
| | - L. Montanaro
- Research Unit on Implant Infections, Rizzoli Orthopedic Institute, Bologna - Italy
- Department of Experimental Pathology of the University of Bologna, Bologna - Italy
| | - C.R. Arciola
- Research Unit on Implant Infections, Rizzoli Orthopedic Institute, Bologna - Italy
- Department of Experimental Pathology of the University of Bologna, Bologna - Italy
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21
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Parallel Evolution of Group B Streptococcus Hypervirulent Clonal Complex 17 Unveils New Pathoadaptive Mutations. mSystems 2017; 2:mSystems00074-17. [PMID: 28904998 PMCID: PMC5585690 DOI: 10.1128/msystems.00074-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/10/2017] [Indexed: 12/21/2022] Open
Abstract
The incidence of group B Streptococcus (GBS) neonatal disease continues to be a significant cause of concern worldwide. Strains belonging to clonal complex 17 (CC17) are the most frequently responsible for GBS infections in neonates, especially among late-onset disease cases. Therefore, we undertook the largest genomic study of GBS CC17 strains to date to decipher the genetic bases of their remarkable colonization and infection ability. We show that crucial functions involved in different steps of the colonization or infection process of GBS are distinctly mutated during the adaptation of CC17 to the human host. In particular, our results implicate the CovRS two-component regulator of virulence in the differentiation between carriage- and disease-associated isolates. Not only does this work raise important implications for the ongoing development of a vaccine against GBS but might also drive the discovery of key functions for GBS adaptation and pathogenesis that have been overlooked until now. Group B Streptococcus (GBS) is a commensal of the gastrointestinal and genitourinary tracts, while a prevailing cause of neonatal disease worldwide. Of the various clonal complexes (CCs), CC17 is overrepresented in GBS-infected newborns for reasons that are still largely unknown. Here, we report a comprehensive genomic analysis of 626 CC17 isolates collected worldwide, identifying the genetic traits behind their successful adaptation to humans and the underlying differences between carriage and clinical strains. Comparative analysis with 923 GBS genomes belonging to CC1, CC19, and CC23 revealed that the evolution of CC17 is distinct from that of other human-adapted lineages and recurrently targets functions related to nucleotide and amino acid metabolism, cell adhesion, regulation, and immune evasion. We show that the most distinctive features of disease-specific CC17 isolates were frequent mutations in the virulence-associated CovS and Stk1 kinases, underscoring the crucial role of the entire CovRS regulatory pathway in modulating the pathogenicity of GBS. Importantly, parallel and convergent evolution of major components of the bacterial cell envelope, such as the capsule biosynthesis operon, the pilus, and Rib, reflects adaptation to host immune pressures and should be taken into account in the ongoing development of a GBS vaccine. The presence of recurrent targets of evolution not previously implicated in virulence also opens the way for uncovering new functions involved in host colonization and GBS pathogenesis. IMPORTANCE The incidence of group B Streptococcus (GBS) neonatal disease continues to be a significant cause of concern worldwide. Strains belonging to clonal complex 17 (CC17) are the most frequently responsible for GBS infections in neonates, especially among late-onset disease cases. Therefore, we undertook the largest genomic study of GBS CC17 strains to date to decipher the genetic bases of their remarkable colonization and infection ability. We show that crucial functions involved in different steps of the colonization or infection process of GBS are distinctly mutated during the adaptation of CC17 to the human host. In particular, our results implicate the CovRS two-component regulator of virulence in the differentiation between carriage- and disease-associated isolates. Not only does this work raise important implications for the ongoing development of a vaccine against GBS but might also drive the discovery of key functions for GBS adaptation and pathogenesis that have been overlooked until now. Author Video: An author video summary of this article is available.
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22
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Seepersaud R, Sychantha D, Bensing BA, Clarke AJ, Sullam PM. O-acetylation of the serine-rich repeat glycoprotein GspB is coordinated with accessory Sec transport. PLoS Pathog 2017; 13:e1006558. [PMID: 28827841 PMCID: PMC5578698 DOI: 10.1371/journal.ppat.1006558] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/31/2017] [Accepted: 07/28/2017] [Indexed: 11/17/2022] Open
Abstract
The serine-rich repeat (SRR) glycoproteins are a family of adhesins found in many Gram-positive bacteria. Expression of the SRR adhesins has been linked to virulence for a variety of infections, including streptococcal endocarditis. The SRR preproteins undergo intracellular glycosylation, followed by export via the accessory Sec (aSec) system. This specialized transporter is comprised of SecA2, SecY2 and three to five accessory Sec proteins (Asps) that are required for export. Although the post-translational modification and transport of the SRR adhesins have been viewed as distinct processes, we found that Asp2 of Streptococcus gordonii also has an important role in modifying the SRR adhesin GspB. Biochemical analysis and mass spectrometry indicate that Asp2 is an acetyltransferase that modifies N-acetylglucosamine (GlcNAc) moieties on the SRR domains of GspB. Targeted mutations of the predicted Asp2 catalytic domain had no effect on transport, but abolished acetylation. Acetylated forms of GspB were only detected when the protein was exported via the aSec system, but not when transport was abolished by secA2 deletion. In addition, GspB variants rerouted to export via the canonical Sec pathway also lacked O-acetylation, demonstrating that this modification is specific to export via the aSec system. Streptococci expressing GspB lacking O-acetylated GlcNAc were significantly reduced in their ability bind to human platelets in vitro, an interaction that has been strongly linked to virulence in the setting of endocarditis. These results demonstrate that Asp2 is a bifunctional protein involved in both the post-translational modification and transport of SRR glycoproteins. In addition, these findings indicate that these processes are coordinated during the biogenesis of SRR glycoproteins, such that the adhesin is optimally modified for binding. This requirement for the coupling of modification and export may explain the co-evolution of the SRR glycoproteins with their specialized glycan modifying and export systems.
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Affiliation(s)
- Ravin Seepersaud
- San Francisco Veteran Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA, United States of America
| | - David Sychantha
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Barbara A Bensing
- San Francisco Veteran Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA, United States of America
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Paul M Sullam
- San Francisco Veteran Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA, United States of America
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Gram-Positive Uropathogens, Polymicrobial Urinary Tract Infection, and the Emerging Microbiota of the Urinary Tract. Microbiol Spectr 2017; 4. [PMID: 27227294 DOI: 10.1128/microbiolspec.uti-0012-2012] [Citation(s) in RCA: 198] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Gram-positive bacteria are a common cause of urinary-tract infection (UTI), particularly among individuals who are elderly, pregnant, or who have other risk factors for UTI. Here we review the epidemiology, virulence mechanisms, and host response to the most frequently isolated Gram-positive uropathogens: Staphylococcus saprophyticus, Enterococcus faecalis, and Streptococcus agalactiae. We also review several emerging, rare, misclassified, and otherwise underreported Gram-positive pathogens of the urinary tract including Aerococcus, Corynebacterium, Actinobaculum, and Gardnerella. The literature strongly suggests that urologic diseases involving Gram-positive bacteria may be easily overlooked due to limited culture-based assays typically utilized for urine in hospital microbiology laboratories. Some UTIs are polymicrobial in nature, often involving one or more Gram-positive bacteria. We herein review the risk factors and recent evidence for mechanisms of bacterial synergy in experimental models of polymicrobial UTI. Recent experimental data has demonstrated that, despite being cleared quickly from the bladder, some Gram-positive bacteria can impact pathogenic outcomes of co-infecting organisms. When taken together, the available evidence argues that Gram-positive bacteria are important uropathogens in their own right, but that some can be easily overlooked because they are missed by routine diagnostic methods. Finally, a growing body of evidence demonstrates that a surprising variety of fastidious Gram-positive bacteria may either reside in or be regularly exposed to the urinary tract and further suggests that their presence is widespread among women, as well as men. Experimental studies in this area are needed; however, there is a growing appreciation that the composition of bacteria found in the bladder could be a potentially important determinant in urologic disease, including susceptibility to UTI.
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24
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Two repetitive, biofilm-forming proteins from Staphylococci: from disorder to extension. Biochem Soc Trans 2016; 43:861-6. [PMID: 26517895 DOI: 10.1042/bst20150088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Staphylococcus aureus and Staphylococcus epidermidis are an important cause of medical device-related infections that are difficult to treat with antibiotics. Biofilms, in which bacteria are embedded in a bacterially-produced exopolymeric matrix, form on the surface of the implanted medical device. Our understanding of the molecular mechanisms underlying the initial surface attachment and subsequent intercellular interactions as the biofilm matures is improving. Biofilm accumulation can be mediated by a partially deacetylated form of poly-N-acetylglucosamine (PNAG) but, more recently, the role of bacterial surface proteins is being recognized. Here we describe the structure and function of two S. aureus cell surface proteins, FnBPA and SasG, implicated in host interactions and biofilm accumulation. These multifunctional proteins employ intrinsic disorder for distinct molecular outcomes. In the case of FnBPA, disorder generates adhesive arrays that bind fibronectin (Fn); in the case of SasG, disorder is, counterintuitively, used to maintain a strong extended fold.
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25
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Chukwu MO, Mavenyengwa RT, Monyama CM, Bolukaoto JY, Lebelo SL, Maloba MR, Nchabeleng M, Moyo SR. Antigenic distribution of Streptococcus agalactiae isolates from pregnant women at Garankuwa hospital - South Africa. Germs 2015; 5:125-33. [PMID: 26716101 DOI: 10.11599/germs.2015.1080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/27/2015] [Accepted: 11/06/2015] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Streptococcus agalactiae (group B streptococcus; GBS) is globally recognised as one of the leading causes of neonatal sepsis and meningitis. It also causes adverse pregnancy outcomes such as stillbirth and miscarriages. Incidence of invasive disease is increasing in non-pregnant adults with underlying medical conditions (e.g., diabetes mellitus). Epidemiological studies of GBS infections are based on capsular serotyping. Genotyping of the surface anchored protein genes is also becoming an important tool for GBS studies. Currently ten different GBS serotypes have been identified. This study was performed to determine the prevalence of GBS capsular types (CTs) and surface anchored protein genes in isolates from colonized pregnant women attending antenatal clinic, at Dr George Mukhari Academic Hospital, Garankuwa, Pretoria, South Africa. METHODS The samples were collected over 11 months and cultured on selective media. GBS was identified using different morphological and biochemical tests. Capsular typing was done using latex agglutination test and conventional PCR. Multiplex PCR with specific primers was used to detect the surface anchored protein genes. RESULTS Of the 413 pregnant women recruited, 128 (30.9%) were colonized with GBS. The capsular polysaccharide (CPS) typing test showed that CPS type III (29.7%) was the most prevalent capsular type followed by CPS type Ia (25.8%), II (15.6%), IV (8.6%), V (10.9%) and Ib (8.6%); 0.7% of the isolates were nontypeable. Multiplex PCR revealed that the surface proteins genes were possessed by all the capsular types: rib (44.5%), bca (24.7%), alp2/3 (17.9%), epsilon (8.6%) and alp4 (4.7%). CONCLUSION The common capsular types found in this study are Ia, III, and II. The most common protein genes identified were rib and bca, and the distribution of the surface protein genes among the isolates of different capsular types showed similar trends to the distribution reported from previous studies.
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Affiliation(s)
- Martina O Chukwu
- MSc, Department of Life and Consumer Science, School of Agriculture and Life Sciences University of South Africa (UNISA), Florida Campus, Pretoria, South Africa
| | - Rooyen Tinago Mavenyengwa
- MSc, DPhil, Department of Medical Microbiology, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe, Department of Health Sciences, School of Health and Applied Sciences, Polytechnic of Namibia, Windhoek, Namibia
| | - Charles M Monyama
- MSc, Department of Life and Consumer Science, School of Agriculture and Life Sciences University of South Africa (UNISA), Florida Campus, Pretoria, South Africa
| | - John Y Bolukaoto
- MSc, Department of Life and Consumer Science, School of Agriculture and Life Sciences University of South Africa (UNISA), Florida Campus, Pretoria, South Africa
| | - Sogolo L Lebelo
- MSc, PhD, Department of Life and Consumer Science, School of Agriculture and Life Sciences University of South Africa (UNISA), Florida Campus, Pretoria, South Africa
| | - Motlatji Rb Maloba
- MD, Department of Microbiological Pathology, University of Limpopo (MEDUNSA), Pretoria, South Africa
| | - Maphoshane Nchabeleng
- MD, PhD, Department of Microbiological Pathology, University of Limpopo (MEDUNSA), Pretoria, South Africa
| | - Sylvester Rogers Moyo
- MSc, DPhil, Department of Health Sciences, School of Health and Applied Sciences, Polytechnic of Namibia, Windhoek, Namibia
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Siarkou VI, Vorimore F, Vicari N, Magnino S, Rodolakis A, Pannekoek Y, Sachse K, Longbottom D, Laroucau K. Diversification and Distribution of Ruminant Chlamydia abortus Clones Assessed by MLST and MLVA. PLoS One 2015; 10:e0126433. [PMID: 26001070 PMCID: PMC4441495 DOI: 10.1371/journal.pone.0126433] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Accepted: 04/02/2015] [Indexed: 11/18/2022] Open
Abstract
Chlamydia abortus, an obligate intracellular bacterium, is the most common infectious cause of abortion in small ruminants worldwide and has zoonotic potential. We applied multilocus sequence typing (MLST) together with multiple-locus variable-number tandem repeat analysis (MLVA) to genotype 94 ruminant C. abortus strains, field isolates and samples collected from 1950 to 2011 in diverse geographic locations, with the aim of delineating C. abortus lineages and clones. MLST revealed the previously identified sequence types (STs) ST19, ST25, ST29 and ST30, plus ST86, a recently-assigned type on the Chlamydiales MLST website and ST87, a novel type harbouring the hemN_21 allele, whereas MLVA recognized seven types (MT1 to MT7). Minimum-spanning-tree analysis suggested that all STs but one (ST30) belonged to a single clonal complex, possibly reflecting the short evolutionary timescale over which the predicted ancestor (ST19) has diversified into three single-locus variants (ST86, ST87 and ST29) and further, through ST86 diversification, into one double-locus variant (ST25). ST descendants have probably arisen through a point mutation evolution mode. Interestingly, MLVA showed that in the ST19 population there was a greater genetic diversity than in other STs, most of which exhibited the same MT over time and geographical distribution. However, the evolutionary pathways of C. abortus STs seem to be diverse across geographic distances with individual STs restricted to particular geographic locations. The ST30 singleton clone displaying geographic specificity and represented by the Greek strains LLG and POS was effectively distinguished from the clonal complex lineage, supporting the notion that possibly two separate host adaptations and hence independent bottlenecks of C. abortus have occurred through time. The combination of MLST and MLVA assays provides an additional level of C. abortus discrimination and may prove useful for the investigation and surveillance of emergent C. abortus clonal populations.
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Affiliation(s)
- Victoria I. Siarkou
- Laboratory of Microbiology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
- * E-mail: (KL); (VIS)
| | - Fabien Vorimore
- Anses, Animal Health Laboratory, Bacterial Zoonoses Unit, University Paris-Est, Maisons-Alfort, France
| | - Nadia Vicari
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Sezione Diagnostica di Pavia, Pavia, Italy
| | - Simone Magnino
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Sezione Diagnostica di Pavia, Pavia, Italy
| | - Annie Rodolakis
- INRA, Infectiologie Animale et Santé Publique, Nouzilly, France
| | - Yvonne Pannekoek
- Academic Medical Center, Department of Medical Microbiology, University of Amsterdam, Amsterdam, The Netherlands
| | - Konrad Sachse
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut (Federal Research Institute for Animal Health), Jena, Germany
| | - David Longbottom
- Moredun Research Institute, Edinburgh, Midlothian, United Kingdom
| | - Karine Laroucau
- Anses, Animal Health Laboratory, Bacterial Zoonoses Unit, University Paris-Est, Maisons-Alfort, France
- * E-mail: (KL); (VIS)
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Mesarich CH, Bowen JK, Hamiaux C, Templeton MD. Repeat-containing protein effectors of plant-associated organisms. FRONTIERS IN PLANT SCIENCE 2015; 6:872. [PMID: 26557126 PMCID: PMC4617103 DOI: 10.3389/fpls.2015.00872] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/01/2015] [Indexed: 05/10/2023]
Abstract
Many plant-associated organisms, including microbes, nematodes, and insects, deliver effector proteins into the apoplast, vascular tissue, or cell cytoplasm of their prospective hosts. These effectors function to promote colonization, typically by altering host physiology or by modulating host immune responses. The same effectors however, can also trigger host immunity in the presence of cognate host immune receptor proteins, and thus prevent colonization. To circumvent effector-triggered immunity, or to further enhance host colonization, plant-associated organisms often rely on adaptive effector evolution. In recent years, it has become increasingly apparent that several effectors of plant-associated organisms are repeat-containing proteins (RCPs) that carry tandem or non-tandem arrays of an amino acid sequence or structural motif. In this review, we highlight the diverse roles that these repeat domains play in RCP effector function. We also draw attention to the potential role of these repeat domains in adaptive evolution with regards to RCP effector function and the evasion of effector-triggered immunity. The aim of this review is to increase the profile of RCP effectors from plant-associated organisms.
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Affiliation(s)
- Carl H. Mesarich
- School of Biological Sciences, The University of AucklandAuckland, New Zealand
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
- *Correspondence: Carl H. Mesarich
| | - Joanna K. Bowen
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
| | - Cyril Hamiaux
- Human Responses, The New Zealand Institute for Plant & Food Research LimitedAuckland, New Zealand
| | - Matthew D. Templeton
- School of Biological Sciences, The University of AucklandAuckland, New Zealand
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
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Survey of immunological features of the alpha-like proteins of Streptococcus agalactiae. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 22:153-9. [PMID: 25540270 DOI: 10.1128/cvi.00643-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Nearly all Streptococcus agalactiae (group B streptococcus [GBS]) strains express a protein which belongs to the so-called alpha-like proteins (Alps), of which Cα, Alp1, Alp2, Alp3, Rib, and Alp4 are known to occur in GBS. The Alps are chimeras which form mosaic structures on the GBS surface. Both N- and C-terminal stretches of the Alps possess immunogenic sites of dissimilar immunological specificity. In this review, we have compiled data dealing with the specificity of the N- and C-terminal immunogenic sites of the Alps. The majority of N-terminal sites show protein specificity while the C-terminal sites show broader cross-reactivity. Molecular serotyping has revealed that antibody-based serotyping has often resulted in erroneous Alp identification, due to persistence of cross-reacting antibodies in antisera for serotyping. Retrospectively, this could be expected on the basis of sequence analysis results. Some of the historical R proteins are in fact Alps. The data included in the review may provide a basis for decisions regarding techniques for the preparation of specific antisera for serotyping of GBS, for use in other approaches in GBS research, and for decision making in the context of GBS vaccine developments.
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Landwehr-Kenzel S, Henneke P. Interaction of Streptococcus agalactiae and Cellular Innate Immunity in Colonization and Disease. Front Immunol 2014; 5:519. [PMID: 25400631 PMCID: PMC4212683 DOI: 10.3389/fimmu.2014.00519] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/05/2014] [Indexed: 12/18/2022] Open
Abstract
Streptococcus agalactiae (Group B streptococcus, GBS) is highly adapted to humans, where it is a normal constituent of the intestinal and vaginal flora. Yet, GBS has highly invasive potential and causes excessive inflammation, sepsis, and death at the beginning of life, in the elderly and in diabetic patients. Thus, GBS is a model pathobiont that thrives in the healthy host, but has not lost its potential virulence during coevolution with mankind. It remains incompletely understood how the innate immune system contains GBS in the natural niches, the intestinal and genital tracts, and which molecular events underlie breakdown of mucocutaneous resistance. Newborn infants between days 7 and 90 of life are at risk of a particularly striking sepsis manifestation (late-onset disease), where the transition from colonization to invasion and dissemination, and thus from health to severe sepsis is typically fulminant and not predictable. The great majority of late-onset sepsis cases are caused by one clone, GBS ST17, which expresses HvgA as a signature virulence factor and adhesin. In mice, HvgA promotes the crossing of both the mucosal and the blood–brain barrier. Expression levels of HvgA and other GBS virulence factors, such as pili and toxins, are regulated by the upstream two-component control system CovR/S. This in turn is modulated by acidic epithelial pH, high glucose levels, and during the passage through the mouse intestine. After invasion, GBS has the ability to subvert innate immunity by mechanisms like glycerinaldehyde-3-phosphate-dehydrogenase-dependent induction of IL-10 and β-protein binding to the inhibitory phagocyte receptors sialic acid binding immunoglobulin-like lectin 5 and 14. On the host side, sensing of GBS nucleic acids and lipopeptides by both Toll-like receptors and the inflammasome appears to be critical for host resistance against GBS. Yet, comprehensive models on the interplay between GBS and human immune cells at the colonizing site are just emerging.
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Affiliation(s)
- Sybille Landwehr-Kenzel
- Berlin-Brandenburg Center for Regenerative Therapies, Charité University Medicine Berlin , Berlin , Germany ; Berlin-Brandenburg School for Regenerative Therapies, Charité University Medicine Berlin , Berlin , Germany ; Department of Pediatric Pulmonology and Immunology, Charité University Medicine Berlin , Berlin , Germany
| | - Philipp Henneke
- Center for Pediatrics and Adolescent Medicine, University Medical Center Freiburg , Freiburg , Germany ; Center for Chronic Immunodeficiency, University Medical Center Freiburg , Freiburg , Germany
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Pertussis resurgence: waning immunity and pathogen adaptation - two sides of the same coin. Epidemiol Infect 2013; 142:685-94. [PMID: 23406868 DOI: 10.1017/s0950268813000071] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Pertussis or whooping cough has persisted and resurged in the face of vaccination and has become one of the most prevalent vaccine-preventable diseases in Western countries. The high circulation rate of Bordetella pertussis poses a threat to infants that have not been (completely) vaccinated and for whom pertussis is a severe, life-threatening, disease. The increase in pertussis is mainly found in age groups in which immunity has waned and this has resulted in the perception that waning immunity is the main or exclusive cause for the resurgence of pertussis. However, significant changes in B. pertussis populations have been observed after the introduction of vaccinations, suggesting a role for pathogen adaptation in the persistence and resurgence of pertussis. These changes include antigenic divergence with vaccine strains and increased production of pertussis toxin. Antigenic divergence will affect both memory recall and the efficacy of antibodies, while higher levels of pertussis toxin may increase suppression of the innate and acquired immune system. We propose these adaptations of B. pertussis have decreased the period in which pertussis vaccines are effective and thus enhanced the waning of immunity. We plead for a more integrated approach to the pertussis problem which includes the characteristics of the vaccines, the B. pertussis populations and the interaction between the two.
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Zhou K, Michiels CW, Aertsen A. Variation of intragenic tandem repeat tract of tolA modulates Escherichia coli stress tolerance. PLoS One 2012; 7:e47766. [PMID: 23094082 PMCID: PMC3477136 DOI: 10.1371/journal.pone.0047766] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 09/20/2012] [Indexed: 11/18/2022] Open
Abstract
In recent work we discovered that the intragenic tandem repeat (TR) region of the tolA gene is highly variable among different Escherichia coli strains. The aim of this study was therefore to investigate the biological function and dynamics of TR variation in E. coli tolA. The biological impact of TR variation was examined by comparing the ability of a set of synthetic tolA variants with in frame repeat copies varying from 2 to 39 to rescue the altered susceptibility of an E. coli ΔtolA mutant to deoxycholic acid, sodium dodecyl sulfate, hyperosmolarity, and infection with filamentous bacteriophage. Interestingly, although each of the TolA variants was able to at least partly rescue the ΔtolA mutant, the extent was clearly dependent on both the repeat number and the type of stress imposed, indicating the existence of opposing selective forces with regard to the optimal TR copy number. Subsequently, TR dynamics in a clonal population were assayed, and we could demonstrate that TR contractions are RecA dependent and enhanced in a DNA repair deficient uvrD background, and can occur at a frequency of 6.9×10−5.
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Affiliation(s)
- Kai Zhou
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (MS), Faculty of Bioscience Engineering, KU Leuven, Leuven, Belgium
| | - Chris W. Michiels
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (MS), Faculty of Bioscience Engineering, KU Leuven, Leuven, Belgium
| | - Abram Aertsen
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (MS), Faculty of Bioscience Engineering, KU Leuven, Leuven, Belgium
- * E-mail:
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Kuriakose JA, Zhang X, Luo T, McBride JW. Molecular basis of antibody mediated immunity against Ehrlichia chaffeensis involves species-specific linear epitopes in tandem repeat proteins. Microbes Infect 2012; 14:1054-63. [PMID: 22658957 PMCID: PMC3445803 DOI: 10.1016/j.micinf.2012.05.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 05/10/2012] [Accepted: 05/18/2012] [Indexed: 01/06/2023]
Abstract
Humoral immune mechanisms are an important component of protective immunity to Ehrlichia species. However, the molecular basis of antibody mediated immunity is not completely defined, and the role of most molecularly characterized major immunoreactive proteins is unknown. In previous studies, we mapped major species-specific continuous epitopes in three surface exposed and secreted tandem repeat proteins (TRP32, TRP47 and TRP120). In this study, we report that protection is provided by antibodies against these molecularly defined TRP epitopes using in vitro and in vivo models. Protection was demonstrated in vitro after prophylactic and therapeutic administration of epitope-specific anti-TRP antibodies, suggesting that the protective mechanisms involve extracellular and intracellular antibody-mediated effects. In vivo passive transfer of individual epitope-specific TRP sera significantly reduced the ehrlichial load and splenomegaly, and protected mice against lethal infection. Moreover, the combination of antibodies to all three TRPs provided enhanced reduction in ehrlichial load similar to that of Ehrlichia chaffeensis immune sera. IgG1 was the predominant antibody isotype in the epitope-specific TRP mouse sera. These results demonstrate that antibodies against linear epitopes in TRP32, TRP47 and TRP120 are protective during E. chaffeensis infection and involves extracellular and intracellular antibody-mediated mechanisms.
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Affiliation(s)
- Jeeba A. Kuriakose
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Xiaofeng Zhang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Tian Luo
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Jere W. McBride
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity University of Texas Medical Branch, Galveston, TX, United States
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The accessory Sec protein Asp2 modulates GlcNAc deposition onto the serine-rich repeat glycoprotein GspB. J Bacteriol 2012; 194:5564-75. [PMID: 22885294 DOI: 10.1128/jb.01000-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The accessory Sec system is a specialized transport system that exports serine-rich repeat (SRR) glycoproteins of Gram-positive bacteria. This system contains two homologues of the general secretory (Sec) pathway (SecA2 and SecY2) and several other essential proteins (Asp1 to Asp5) that share no homology to proteins of known function. In Streptococcus gordonii, Asp2 is required for the transport of the SRR adhesin GspB, but its role in export is unknown. Tertiary structure predictions suggest that the carboxyl terminus of Asp2 resembles the catalytic region of numerous enzymes that function through a Ser-Asp-His catalytic triad. Sequence alignment of all Asp2 homologues identified a highly conserved pentapeptide motif (Gly-X-Ser(362)-X-Gly) typical of most Ser-Asp-His catalytic triads, where Ser forms the reactive residue. Site-directed mutagenesis of residues comprising the predicted catalytic triad of Asp2 of S. gordonii had no effect upon GspB transport but did result in a marked change in the electrophoretic mobility of the protein. Lectin-binding studies and monosaccharide content analysis of this altered glycoform revealed an increase in glucosamine deposition. Random mutagenesis of the Asp2 region containing this catalytic domain also disrupted GspB transport. Collectively, our findings suggest that Asp2 is a bifunctional protein that is essential for both GspB transport and correct glycosylation. The catalytic domain may be responsible for controlling the glycosylation of GspB, while other surrounding regions are functionally required for glycoprotein transport.
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34
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Variability of the tandem repeat region of the Escherichia coli tolA gene. Res Microbiol 2012; 163:316-22. [DOI: 10.1016/j.resmic.2012.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 05/03/2012] [Indexed: 11/23/2022]
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Abstract
The infection of mice with Mycoplasma pulmonis is a model for studying chronic mycoplasmal respiratory disease. Many in vivo and in vitro studies have used the organism to gain a better understanding of host-pathogen interactions in chronic respiratory infection. The organism's Vsa proteins contain an extensive tandem repeat region. The length of the tandem repeat unit varies from as few as 11 amino acids to as many as 19. The number of tandem repeats can be as high as 60. The number of repeats varies at a high frequency due to slipped-strand mispairing events that occur during DNA replication. When the number of repeats is high, e.g., 40, the mycoplasma is resistant to lysis by complement but does not form a robust biofilm. When the number of repeats is low, e.g., 5, the mycoplasma is killed by complement when the cells are dispersed but has the capacity to form a biofilm that resists complement. Here, we examine the role of the Vsa proteins in the avoidance of phagocytosis and find that cells producing a protein with many tandem repeats are relatively resistant to killing by macrophages. These results may be pertinent to understanding the functions of similar proteins that have extensive repeat regions in other microbes.
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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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Zhou L, Powell CA, Hoffman MT, Li W, Fan G, Liu B, Lin H, Duan Y. Diversity and plasticity of the intracellular plant pathogen and insect symbiont "Candidatus Liberibacter asiaticus" as revealed by hypervariable prophage genes with intragenic tandem repeats. Appl Environ Microbiol 2011; 77:6663-73. [PMID: 21784907 PMCID: PMC3187138 DOI: 10.1128/aem.05111-11] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 07/15/2011] [Indexed: 11/20/2022] Open
Abstract
"Candidatus Liberibacter asiaticus" is a psyllid-transmitted, phloem-limited alphaproteobacterium and the most prevalent species of "Ca. Liberibacter" associated with a devastating worldwide citrus disease known as huanglongbing (HLB). Two related and hypervariable genes (hyv(I) and hyv(II)) were identified in the prophage regions of the Psy62 "Ca. Liberibacter asiaticus" genome. Sequence analyses of the hyv(I) and hyv(II) genes in 35 "Ca. Liberibacter asiaticus" DNA isolates collected globally revealed that the hyv(I) gene contains up to 12 nearly identical tandem repeats (NITRs, 132 bp) and 4 partial repeats, while hyv(II) contains up to 2 NITRs and 4 partial repeats and shares homology with hyv(I). Frequent deletions or insertions of these repeats within the hyv(I) and hyv(II) genes were observed, none of which disrupted the open reading frames. Sequence conservation within the individual repeats but an extensive variation in repeat numbers, rearrangement, and the sequences flanking the repeat region indicate the diversity and plasticity of "Ca. Liberibacter asiaticus" bacterial populations in the world. These differences were found not only in samples of distinct geographical origins but also in samples from a single origin and even from a single "Ca. Liberibacter asiaticus"-infected sample. This is the first evidence of different "Ca. Liberibacter asiaticus" populations coexisting in a single HLB-affected sample. The Florida "Ca. Liberibacter asiaticus" isolates contain both hyv(I) and hyv(II), while all other global "Ca. Liberibacter asiaticus" isolates contain either one or the other. Interclade assignments of the putative Hyv(I) and Hyv(II) proteins from Florida isolates with other global isolates in phylogenetic trees imply multiple "Ca. Liberibacter asiaticus" populations in the world and a multisource introduction of the "Ca. Liberibacter asiaticus" bacterium into Florida.
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Affiliation(s)
- Lijuan Zhou
- University of Florida, IFAS-IRREC, Ft. Pierce, Florida 34945
| | | | | | - Wenbin Li
- USDA-APHIS-PPQ-CPHST-NPGBL, Beltsville, Maryland 20705
| | - Guocheng Fan
- Citrus Huanglongbing Research Center, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350002, China
| | - Bo Liu
- Citrus Huanglongbing Research Center, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350002, China
| | - Hong Lin
- San Joaquin Valley Agricultural Sciences Center, USDA-ARS, Parlier, California 93658
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Haguenoer E, Baty G, Pourcel C, Lartigue MF, Domelier AS, Rosenau A, Quentin R, Mereghetti L, Lanotte P. A multi locus variable number of tandem repeat analysis (MLVA) scheme for Streptococcus agalactiae genotyping. BMC Microbiol 2011; 11:171. [PMID: 21794143 PMCID: PMC3163538 DOI: 10.1186/1471-2180-11-171] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 07/27/2011] [Indexed: 11/10/2022] Open
Abstract
Background Multilocus sequence typing (MLST) is currently the reference method for genotyping Streptococcus agalactiae strains, the leading cause of infectious disease in newborns and a major cause of disease in immunocompromised children and adults. We describe here a genotyping method based on multiple locus variable number of tandem repeat (VNTR) analysis (MLVA) applied to a population of S. agalactiae strains of various origins characterized by MLST and serotyping. Results We studied a collection of 186 strains isolated from humans and cattle and three reference strains (A909, NEM316 and 2603 V/R). Among 34 VNTRs, 6 polymorphic VNTRs loci were selected for use in genotyping of the bacterial population. The MLVA profile consists of a series of allele numbers, corresponding to the number of repeats at each VNTR locus. 98 MLVA genotypes were obtained compared to 51 sequences types generated by MLST. The MLVA scheme generated clusters which corresponded well to the main clonal complexes obtained by MLST. However it provided a higher discriminatory power. The diversity index obtained with MLVA was 0.960 compared to 0.881 with MLST for this population of strains. Conclusions The MLVA scheme proposed here is a rapid, cheap and easy genotyping method generating results suitable for exchange and comparison between different laboratories and for the epidemiologic surveillance of S. agalactiae and analyses of outbreaks.
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Affiliation(s)
- Eve Haguenoer
- Université François-Rabelais de Tours, UFR de Médecine, EA 3854 Bactéries et risque materno-fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, Tours, France
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Goto Y, Duthie MS, Kawazu SI, Inoue N, Carter D. Biased cellular locations of tandem repeat antigens in African trypanosomes. Biochem Biophys Res Commun 2011; 405:434-8. [PMID: 21241659 PMCID: PMC3042534 DOI: 10.1016/j.bbrc.2011.01.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 01/12/2011] [Indexed: 02/04/2023]
Abstract
Trypanosoma brucei subspecies cause African trypanosomiasis in humans and animals. These parasites possess genes encoding proteins with large tandem repeat (TR) domains as do the other trypanosomatid parasites. We have previously demonstrated that TR protein of Leishmania infantum and Trypanosoma cruzi are often targets of B-cell responses. However, African trypanosomes are susceptible to antibody-mediated immunity, and it may be detrimental for the parasites to have such B-cell antigens on the cell surface. Here we show TR proteins of T. brucei subspecies are also antigenic: recombinant TR proteins of these parasites detect antibodies in sera from mice infected with the parasites by ELISA. Analysis of amino acid sequences revealed that, different from TR proteins of Leishmania species or T. cruzi, the presence of predicted signal peptides, trans-membrane domains and GPI anchor signals in T. brucei TR proteins are significantly lower than those of the whole proteome. Many of the T. brucei TR proteins are specific in the species or conserved only in the closely related species, as is the same case for Leishmania major and T. cruzi. These results suggest that, despite their sharing some common characteristics, such abundance in large TR domains and immunological dominance, TR genes have evolved independently among the trypanosomatid parasites.
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Affiliation(s)
- Yasuyuki Goto
- Laboratory of Molecular Immunology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan.
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Calvo-Bado LA, Green LE, Medley GF, Ul-Hassan A, Grogono-Thomas R, Buller N, Kaler J, Russell CL, Kennan RM, Rood JI, Wellington EMH. Detection and diversity of a putative novel heterogeneous polymorphic proline-glycine repeat (Pgr) protein in the footrot pathogen Dichelobacter nodosus. Vet Microbiol 2011; 147:358-66. [PMID: 20655152 DOI: 10.1016/j.vetmic.2010.06.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 06/23/2010] [Accepted: 06/25/2010] [Indexed: 11/29/2022]
Abstract
Dichelobacter nodosus, a Gram-negative anaerobic bacterium, is the essential causative agent of footrot in sheep. Currently, depending on the clinical presentation in the field, footrot is described as benign or virulent; D. nodosus strains have also been classified as benign or virulent, but this designation is not always consistent with clinical disease. The aim of this study was to determine the diversity of the pgr gene, which encodes a putative proline-glycine repeat protein (Pgr). The pgr gene was present in all 100 isolates of D. nodosus that were examined and, based on sequence analysis had two variants, pgrA and pgrB. In pgrA, there were two coding tandem repeat regions, R1 and R2: different strains had variable numbers of repeats within these regions. The R1 and R2 were absent from pgrB. Both variants were present in strains from Australia, Sweden and the UK, however, only pgrB was detected in isolates from Western Australia. The pgrA gene was detected in D. nodosus from tissue samples from two flocks in the UK with virulent footrot and only pgrB from a flock with no virulent or benign footrot for >10 years. Bioinformatic analysis of the putative PgrA protein indicated that it contained a collagen-like cell surface anchor motif. These results suggest that the pgr gene may be a useful molecular marker for epidemiological studies.
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Affiliation(s)
- Leo A Calvo-Bado
- Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
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Chen F, Liu WQ, Liu ZH, Zou QH, Wang Y, Li YG, Zhou J, Eisenstark A, Johnston RN, Liu GR, Yang BF, Liu SL. mutL as a genetic switch of bacterial mutability: turned on or off through repeat copy number changes. FEMS Microbiol Lett 2010; 312:126-32. [DOI: 10.1111/j.1574-6968.2010.02107.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Seepersaud R, Bensing BA, Yen YT, Sullam PM. Asp3 mediates multiple protein-protein interactions within the accessory Sec system of Streptococcus gordonii. Mol Microbiol 2010; 78:490-505. [PMID: 20807195 DOI: 10.1111/j.1365-2958.2010.07346.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Bacterial binding to human platelets is an important step in the pathogenesis of infective endocarditis. Streptococcus gordonii can mediate its platelet attachment through a cell wall glycoprotein termed GspB ('gordonii surface protein B'). GspB export is mediated by a seven-component accessory Sec system, containing two homologues of the general secretory pathway (SecA2 and SecY2) and five accessory Sec proteins (Asps1-5). Here we show that the Asps are required for optimal export of GspB independent of the glycosylation process. Furthermore, yeast two-hybrid screening of the accessory Sec system revealed interactions occurring between Asp3 and the other components of the system. Asp3 was shown to bind SecA2, Asp1, Asp2 and itself. Mutagenesis of Asp3 identified N- and C-terminal regions that are essential for GspB transport, and conserved residues within the C-terminal domain mediated Asp3 binding to other accessory Sec components. The loss of binding by Asp3 also resulted in an impaired ability of S. gordonii to secrete GspB. These studies indicate that Asp3 is a central element mediating multiple interactions among accessory Sec components that are essential for GspB transport to the cell surface.
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Affiliation(s)
- Ravin Seepersaud
- San Francisco Veteran Affairs Medical Center, University of California, San Francisco, CA 94121, USA
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Coscolla M, Gagneux S. Does M. tuberculosis genomic diversity explain disease diversity? ACTA ACUST UNITED AC 2010; 7:e43-e59. [PMID: 21076640 DOI: 10.1016/j.ddmec.2010.09.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The outcome of tuberculosis infection and disease is highly variable. This variation has been attributed primarily to host and environmental factors, but better understanding of the global genomic diversity in the M. tuberculosis complex (MTBC) suggests that bacterial factors could also be involved. Review of nearly 100 published reports shows that MTBC strains differ in their virulence and immunogenicity in experimental models, but whether this phenotypic variation plays a role in human disease remains unclear. Given the complex interactions between the host, the pathogen and the environment, linking MTBC genotypic diversity to experimental and clinical phenotypes requires an integrated systems epidemiology approach embedded in a robust evolutionary framework.
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Trost E, Götker S, Schneider J, Schneiker-Bekel S, Szczepanowski R, Tilker A, Viehoever P, Arnold W, Bekel T, Blom J, Gartemann KH, Linke B, Goesmann A, Pühler A, Shukla SK, Tauch A. Complete genome sequence and lifestyle of black-pigmented Corynebacterium aurimucosum ATCC 700975 (formerly C. nigricans CN-1) isolated from a vaginal swab of a woman with spontaneous abortion. BMC Genomics 2010; 11:91. [PMID: 20137072 PMCID: PMC2830990 DOI: 10.1186/1471-2164-11-91] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 02/05/2010] [Indexed: 11/10/2022] Open
Abstract
Background Corynebacterium aurimucosum is a slightly yellowish, non-lipophilic, facultative anaerobic member of the genus Corynebacterium and predominantly isolated from human clinical specimens. Unusual black-pigmented variants of C. aurimucosum (originally named as C. nigricans) continue to be recovered from the female urogenital tract and they are associated with complications during pregnancy. C. aurimucosum ATCC 700975 (C. nigricans CN-1) was originally isolated from a vaginal swab of a 34-year-old woman who experienced a spontaneous abortion during month six of pregnancy. For a better understanding of the physiology and lifestyle of this potential urogenital pathogen, the complete genome sequence of C. aurimucosum ATCC 700975 was determined. Results Sequencing and assembly of the C. aurimucosum ATCC 700975 genome yielded a circular chromosome of 2,790,189 bp in size and the 29,037-bp plasmid pET44827. Specific gene sets associated with the central metabolism of C. aurimucosum apparently provide enhanced metabolic flexibility and adaptability in aerobic, anaerobic and low-pH environments, including gene clusters for the uptake and degradation of aromatic amines, L-histidine and L-tartrate as well as a gene region for the formation of selenocysteine and its incorporation into formate dehydrogenase. Plasmid pET44827 codes for a non-ribosomal peptide synthetase that plays the pivotal role in the synthesis of the characteristic black pigment of C. aurimucosum ATCC 700975. Conclusions The data obtained by the genome project suggest that C. aurimucosum could be both a resident of the human gut and possibly a pathogen in the female genital tract causing complications during pregnancy. Since hitherto all black-pigmented C. aurimucosum strains have been recovered from female genital source, biosynthesis of the pigment is apparently required for colonization by protecting the bacterial cells against the high hydrogen peroxide concentration in the vaginal environment. The location of the corresponding genes on plasmid pET44827 explains why black-pigmented (formerly C. nigricans) and non-pigmented C. aurimucosum strains were isolated from clinical specimens.
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Affiliation(s)
- Eva Trost
- Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, D-33615 Bielefeld, Germany
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Said KB, Zhu G, Zhao X. Organ- and Host-Specific Clonal Groups ofStaphylococcus aureusfrom Human Infections and Bovine Mastitis Revealed by the Clumping Factor A Gene. Foodborne Pathog Dis 2010; 7:111-9. [DOI: 10.1089/fpd.2009.0334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Guoqiang Zhu
- Department of Microbiology, College of Veterinary Science, Yanzhou University, Yanzhou, China
| | - Xin Zhao
- Department of Animal Science, McGill University, Quebec, Canada
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Creti R, Fabretti F, Koch S, Huebner J, Garsin DA, Baldassarri L, Montanaro L, Arciola CR. Surface protein EF3314 contributes to virulence properties of Enterococcus faecalis. Int J Artif Organs 2010; 32:611-20. [PMID: 19856273 DOI: 10.1177/039139880903200910] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE Identification of putative new virulence factors as additional targets for therapeutic approaches alternative to antibiotic treatment of multi-resistant enterococcal infections. METHODS The EF3314 gene, coding for a putative surface-exposed antigen, was identified by the analysis of the Enterococcus faecalis V583 genome for LPXTG-motif cell wall anchor surface protein genes. A non-polar EF3314 gene deletion mutant in the E. faecalis 12030 human clinical isolate was obtained. The wild type and the isogenic mutant strain were investigated for biofilm formation, adherence to Hela cells, survival in human macrophages and a Caenorhabditis elegans infection model. The aminoterminal portion of the EF3314 protein was overexpressed in E. coli to obtain mouse polyclonal antibodies for use in Western blotting and immunolocalization experiments. RESULTS The EF3314 gene has an unusually high GC content (46.88% vs. an average of 37.5% in the E. faecalis chromosome) and encodes a protein of 1744 amino acids that presents a series of 14 imperfect repeats of 90 amino acids covering almost the entire length of the protein. Its global organization is similar to the alpha-like protein family of group B streptococci, enterococcal surface protein Esp and biofilm associated protein Bap from S. aureus. The EF3314 gene was always present and specific for E. faecalis strains of human, food and animal origin. Differences in size depended on variable numbers of repeats in the repetitive region. CONCLUSIONS EF3314 is a newly described, surface exposed protein that contributes to the virulence properties of E. faecalis.
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Affiliation(s)
- Roberta Creti
- Respiratory and Systemic Disease Unit, Department of Infectious, Parasitic, and Immune-mediated Diseases, National Health Institute (ISS), Rome, Italy.
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Genomic analysis identifies a transcription-factor binding motif regulating expression of the alpha C protein in Group B Streptococcus. Microb Pathog 2009; 46:315-20. [PMID: 19328843 DOI: 10.1016/j.micpath.2009.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 03/17/2009] [Accepted: 03/18/2009] [Indexed: 11/21/2022]
Abstract
The virulence-associated alpha C protein (ACP) of Group B Streptococcus (GBS) facilitates the bacterial interaction with host epithelial cells. We previously demonstrated that phase-variable expression of ACP is controlled by variation in short-sequence repeat sequences present upstream of the promoter of bca, the gene encoding ACP. To determine if trans-acting transcriptional control also influences ACP expression, we developed an in silico prediction algorithm that identified a potential transcription-factor binding motif (TTT-N(6)-ATAT) in the bca upstream region. In vitro reporter gene expression studies confirmed that this motif is required for full ACP expression, and DNA-binding assays with a GBS protein extract demonstrated that the predicted site is bound by a protein. This approach demonstrates the utility of in silico genomic predictive methods in the study of GBS regulatory mechanisms.
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Abstract
Proteins with tandem repeat (TR) domains have been found in various protozoan parasites, often acting as targets of B-cell responses. However, the extent of the repeats within Trypanosoma cruzi, the causative agent of Chagas' disease, has not been examined well. Here, we present a systematic survey of the TR genes found in T. cruzi, in comparison with other organisms. Although the characteristics of TR genes varied from organism to organism, the presence of genes having large TR domains was unique to the trypanosomatids examined, including T. cruzi. Sequence analyses of T. cruzi TR genes revealed their divergency; they do not share such characteristics as sequence similarity or biased cellular location predicted by the presence of a signal sequence or transmembrane domain(s). In contrast, T. cruzi TR proteins seemed to possess significant antigenicity. A number of previously characterized T. cruzi antigens were detected by this computational screening, and several of those antigens contained a large TR domain. Further analyses of the T. cruzi genome demonstrated that previously uncharacterized TR proteins in this organism may also be immunodominant. Taken together, T. cruzi is rich in large TR domain-containing proteins with immunological significance; it is worthwhile further analyzing such characteristics of TR proteins as the copy number and consensus sequence of the repeats to determine whether they might contribute to the biological variability of T. cruzi strains with regard to induced immunological responses, host susceptibility, disease outcomes, and pathogenicity.
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Nather K, Munro CA. Generating cell surface diversity in Candida albicans and other fungal pathogens. FEMS Microbiol Lett 2008; 285:137-45. [PMID: 18616597 DOI: 10.1111/j.1574-6968.2008.01263.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The fungal cell surface contributes to pathogenesis by mediating interactions with host cells and eliciting host immune responses. This review focuses on the cell wall proteome of the major fungal pathogen Candida albicans and discusses how diversity at the cell surface can be introduced by altering the expression and structure of cell wall proteins. Remodelling the cell wall architecture is critical to maintain cellular integrity in response to different environments and stresses including challenge with antifungal drugs. In addition, the dynamic nature of the cell surface alters the physical properties of the fungal interface with host cells and thereby influences adhesion to the host and recognition by components of the host's immune system. Examples of the role of cell surface diversity in the pathogenesis of a number of microorganisms are described.
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Affiliation(s)
- Kerstin Nather
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
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Harper KN, Liu H, Ocampo PS, Steiner BM, Martin A, Levert K, Wang D, Sutton M, Armelagos GJ. The sequence of the acidic repeat protein (arp) gene differentiates venereal from nonvenereal Treponema pallidum subspecies, and the gene has evolved under strong positive selection in the subspecies that causes syphilis. ACTA ACUST UNITED AC 2008; 53:322-32. [PMID: 18554302 DOI: 10.1111/j.1574-695x.2008.00427.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Despite the completion of the Treponema pallidum genome project, only minor genetic differences have been found between the subspecies that cause venereal syphilis (ssp. pallidum) and the nonvenereal diseases yaws (ssp. pertenue) and bejel (ssp. endemicum). In this paper, we describe sequence variation in the arp gene which allows straightforward differentiation of ssp. pallidum from the nonvenereal subspecies. We also present evidence that this region is subject to positive selection in ssp. pallidum, consistent with pressure from the immune system. Finally, the presence of multiple, but distinct, repeat motifs in both ssp. pallidum and Treponema paraluiscuniculi (the pathogen responsible for rabbit syphilis) suggests that a diverse repertoire of repeat motifs is associated with sexual transmission. This study suggests that variations in the number and sequence of repeat motifs in the arp gene have clinical, epidemiological, and evolutionary significance.
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Affiliation(s)
- Kristin N Harper
- Department of Population Biology, Ecology, and Evolution, Emory University, Atlanta, GA, USA
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