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Increased Intracellular Cyclic di-AMP Levels Sensitize Streptococcus gallolyticus subsp. gallolyticus to Osmotic Stress and Reduce Biofilm Formation and Adherence on Intestinal Cells. J Bacteriol 2019; 201:JB.00597-18. [PMID: 30617242 PMCID: PMC6398277 DOI: 10.1128/jb.00597-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/20/2018] [Indexed: 12/31/2022] Open
Abstract
Streptococcus gallolyticus is an opportunistic pathogen responsible for septicemia and endocarditis in the elderly and is also strongly associated with colorectal cancer. S. gallolyticus can form biofilms, express specific pili to colonize the host tissues, and produce a specific bacteriocin allowing killing of commensal bacteria in the murine colon. Nevertheless, how the expression of these colonization factors is regulated remains largely unknown. Here, we show that c-di-AMP plays pleiotropic roles in S. gallolyticus, controlling the tolerance to osmotic stress, cell size, biofilm formation on abiotic surfaces, adherence and cell aggregation on human intestinal cells, expression of Pil3 pilus, and production of bacteriocin. This study indicates that c-di-AMP may constitute a key regulatory molecule for S. gallolyticus host colonization and pathogenesis. Cyclic di-AMP is a recently identified second messenger exploited by a number of Gram-positive bacteria to regulate important biological processes. Here, we studied the phenotypic alterations induced by the increased intracellular c-di-AMP levels in Streptococcus gallolyticus, an opportunistic pathogen responsible for septicemia and endocarditis in the elderly. We report that an S. gallolyticus c-di-AMP phosphodiesterase gdpP knockout mutant, which displays a 1.5-fold higher intracellular c-di-AMP levels than the parental strain UCN34, is more sensitive to osmotic stress and is morphologically smaller than the parental strain. Unexpectedly, we found that a higher level of c-di-AMP reduced biofilm formation of S. gallolyticus on abiotic surfaces and reduced adherence and cell aggregation on human intestinal cells. A genome-wide transcriptomic analysis indicated that c-di-AMP regulates many biological processes in S. gallolyticus, including the expression of various ABC transporters and disease-associated genes encoding bacteriocin and Pil3 pilus. Complementation of the gdpP in-frame deletion mutant with a plasmid carrying gdpP in trans from its native promoter restored bacterial morphology, tolerance to osmotic stress, biofilm formation, adherence to intestinal cells, bacteriocin production, and Pil3 pilus expression. Our results indicate that c-di-AMP is a pleiotropic signaling molecule in S. gallolyticus that may be important for S. gallolyticus pathogenesis. IMPORTANCEStreptococcus gallolyticus is an opportunistic pathogen responsible for septicemia and endocarditis in the elderly and is also strongly associated with colorectal cancer. S. gallolyticus can form biofilms, express specific pili to colonize the host tissues, and produce a specific bacteriocin allowing killing of commensal bacteria in the murine colon. Nevertheless, how the expression of these colonization factors is regulated remains largely unknown. Here, we show that c-di-AMP plays pleiotropic roles in S. gallolyticus, controlling the tolerance to osmotic stress, cell size, biofilm formation on abiotic surfaces, adherence and cell aggregation on human intestinal cells, expression of Pil3 pilus, and production of bacteriocin. This study indicates that c-di-AMP may constitute a key regulatory molecule for S. gallolyticus host colonization and pathogenesis.
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Armistead B, Oler E, Adams Waldorf K, Rajagopal L. The Double Life of Group B Streptococcus: Asymptomatic Colonizer and Potent Pathogen. J Mol Biol 2019; 431:2914-2931. [PMID: 30711542 DOI: 10.1016/j.jmb.2019.01.035] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 12/22/2022]
Abstract
Group B streptococcus (GBS) is a β-hemolytic gram-positive bacterium that colonizes the lower genital tract of approximately 18% of women globally as an asymptomatic member of the gastrointestinal and/or vaginal flora. If established in other host niches, however, GBS is highly pathogenic. During pregnancy, ascending GBS infection from the vagina to the intrauterine space is associated with preterm birth, stillbirth, and fetal injury. In addition, vertical transmission of GBS during or after birth results in life-threatening neonatal infections, including pneumonia, sepsis, and meningitis. Although the mechanisms by which GBS traffics from the lower genital tract to vulnerable host niches are not well understood, recent advances have revealed that many of the same bacterial factors that promote asymptomatic vaginal carriage also facilitate dissemination and virulence. Furthermore, highly pathogenic GBS strains have acquired unique factors that enhance survival in invasive niches. Several host factors also exist that either subdue GBS upon vaginal colonization or alternatively permit invasive infection. This review summarizes the GBS and host factors involved in GBS's state as both an asymptomatic colonizer and an invasive pathogen. Gaining a better understanding of these mechanisms is key to overcoming the challenges associated with vaccine development and identification of novel strategies to mitigate GBS virulence.
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Affiliation(s)
- Blair Armistead
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle 98101, WA, USA
| | - Elizabeth Oler
- Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle 98195, WA, USA
| | - Kristina Adams Waldorf
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle 98195, WA, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle 98109, WA, USA; Sahlgrenska Academy, Gothenburg University, Gothenburg 413 90, Sweden
| | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle 98101, WA, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle 98195, WA, USA.
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Yang Y, Luo M, Zhou H, Li C, Luk A, Zhao G, Fung K, Ip M. Role of Two-Component System Response Regulator bceR in the Antimicrobial Resistance, Virulence, Biofilm Formation, and Stress Response of Group B Streptococcus. Front Microbiol 2019; 10:10. [PMID: 30728810 PMCID: PMC6351488 DOI: 10.3389/fmicb.2019.00010] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 01/07/2019] [Indexed: 01/31/2023] Open
Abstract
Group B Streptococcus (GBS; Streptococcus agalactiae) is a leading cause of sepsis in neonates and pregnant mothers worldwide. Whereas the hyper-virulent serogroup III clonal cluster 17 has been associated with neonatal disease and meningitis, serogroup III ST283 was recently implicated in invasive disease among non-pregnant adults in Asia. Here, through comparative genome analyses of invasive and non-invasive ST283 strains, we identified a truncated DNA-binding regulator of a two-component system in a non-invasive strain that was homologous to Bacillus subtilis bceR, encoding the bceRSAB response regulator, which was conserved among GBS strains. Using isogenic knockout and complementation mutants of the ST283 strain, we demonstrated that resistance to bacitracin and the human antimicrobial peptide cathelicidin LL-37 was reduced in the ΔbceR strain with MICs changing from 64 and 256 μg/ml to 0.25 and 64 μg/ml, respectively. Further, the ATP-binding cassette transporter was upregulated by sub-inhibitory concentrations of bacitracin in the wild-type strain. Upregulation of dltA in the wild-type strain was also observed and thought to explain the increased resistance to antimicrobial peptides. DltA, an enzyme involved in D-alanylation during the synthesis of wall teichoic acids, which mediates reduced antimicrobial susceptibility, was previously shown to be regulated by the bceR-type regulator in Staphylococcus aureus. In a murine infection model, we found that the ΔbceR mutation significantly reduced the mortality rate compared to that with the wild-type strain (p < 0.01). Moreover, this mutant was more susceptible to oxidative stress compared to the wild-type strain (p < 0.001) and was associated with reduced biofilm formation (p < 0.0001). Based on 2-DGE and mass spectrometry, we showed that downregulation of alkyl hydroperoxide reductase (AhpC), a Gls24 family stress protein, and alcohol dehydrogenase (Adh) in the ΔbceR strain might explain the attenuated virulence and compromised stress response. Together, we showed for the first time that the bceR regulator in GBS plays an important role in bacitracin and antimicrobial peptide resistance, virulence, survival under oxidative stress, and biofilm formation.
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Affiliation(s)
- Ying Yang
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Mingjing Luo
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Haokui Zhou
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Carmen Li
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Alison Luk
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - GuoPing Zhao
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Kitty Fung
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Margaret Ip
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
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54
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Tavares GC, Pereira FL, Barony GM, Rezende CP, da Silva WM, de Souza GHMF, Verano-Braga T, de Carvalho Azevedo VA, Leal CAG, Figueiredo HCP. Delineation of the pan-proteome of fish-pathogenic Streptococcus agalactiae strains using a label-free shotgun approach. BMC Genomics 2019; 20:11. [PMID: 30616502 PMCID: PMC6323687 DOI: 10.1186/s12864-018-5423-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 12/27/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Streptococcus agalactiae (GBS) is a major pathogen of Nile tilapia, a global commodity of the aquaculture sector. The aims of this study were to evaluate protein expression in the main genotypes of GBS isolated from diseased fishes in Brazil using a label-free shotgun nano-liquid chromatography-ultra definition mass spectrometry (nanoLC-UDMSE) approach and to compare the differential abundance of proteins identified in strains isolated from GBS-infected fishes and humans. RESULTS A total of 1070 protein clusters were identified by nanoLC-UDMSE in 5 fish-adapted GBS strains belonging to sequence types ST-260 and ST-927 and the non-typeable (NT) lineage and 1 human GBS strain (ST-23). A total of 1065 protein clusters corresponded to the pan-proteome of fish-adapted GBS strains; 989 of these were identified in all fish-adapted GBS strains (core proteome), and 62 were shared by at least two strains (accessory proteome). Proteins involved in the stress response and in the regulation of gene expression, metabolism and virulence were detected, reflecting the adaptive ability of fish-adapted GBS strains in response to stressor factors that affect bacterial survival in the aquatic environment and bacterial survival and multiplication inside the host cell. Measurement of protein abundance among different hosts showed that 5 and 26 proteins were exclusively found in the human- and fish-adapted GBS strains, respectively; the proteins exclusively identified in fish isolates were mainly related to virulence factors. Furthermore, 215 and 269 proteins were up- and down-regulated, respectively, in the fish-adapted GBS strains in comparison to the human isolate. CONCLUSIONS Our study showed that the core proteome of fish-adapted GBS strains is conserved and demonstrated high similarity of the proteins expressed by fish-adapted strains to the proteome of the human GBS strain. This high degree of proteome conservation of different STs suggests that, a monovalent vaccine may be effective against these variants.
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Affiliation(s)
- Guilherme Campos Tavares
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Felipe Luiz Pereira
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gustavo Morais Barony
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Cristiana Perdigão Rezende
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Wanderson Marques da Silva
- Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Thiago Verano-Braga
- Department of Physiology and Biophysics, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Vasco Ariston de Carvalho Azevedo
- Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Carlos Augusto Gomes Leal
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Henrique César Pereira Figueiredo
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil. .,School of Veterinary, Department of Preventive Veterinary Medicine, Federal University of Minas Gerais, Av. Antônio Carlos 6627, Pampulha, Belo Horizonte, Minas Gerais, 30161-970, Brazil.
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55
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Daudu D, Kisiala A, Werner Ribeiro C, Mélin C, Perrot L, Clastre M, Courdavault V, Papon N, Oudin A, Courtois M, Dugé de Bernonville T, Gaucher M, Degrave A, Lanoue A, Lanotte P, Schouler C, Brisset MN, Emery RN, Pichon O, Carpin S, Giglioli-Guivarc’h N, Crèche J, Besseau S, Glévarec G. Setting-up a fast and reliable cytokinin biosensor based on a plant histidine kinase receptor expressed in Saccharomyces cerevisiae. J Biotechnol 2019; 289:103-111. [DOI: 10.1016/j.jbiotec.2018.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/14/2018] [Accepted: 11/16/2018] [Indexed: 12/21/2022]
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56
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Giussani S, Pietrocola G, Donnarumma D, Norais N, Speziale P, Fabbrini M, Margarit I. The Streptococcus agalactiae complement interfering protein combines multiple complement-inhibitory mechanisms by interacting with both C4 and C3 ligands. FASEB J 2018; 33:4448-4457. [PMID: 30566365 PMCID: PMC6404586 DOI: 10.1096/fj.201801991r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Group B Streptococcus (GBS) colonizes the human lower intestinal and genital tracts and constitutes a major threat to neonates from pregnant carrier mothers and to adults with underlying morbidity. The pathogen expresses cell-surface virulence factors that enable cell adhesion and penetration and that counteract innate and adaptive immune responses. Among these, the complement interfering protein (CIP) was recently described for its capacity to interact with the human C4b ligand and to interfere with the classical- and lectin-complement pathways. In the present study, we provide evidence that CIP can also interact with C3, C3b, and C3d. Immunoassay-based competition experiments showed that binding of CIP to C3d interferes with the interaction between C3d and the complement receptor 2/cluster of differentiation 21 (CR2/CD21) receptor on B cells. By B-cell intracellular signaling assays, CIP was confirmed to down-regulate CR2/CD21-dependent B-cell activation. The CIP domain involved in C3d binding was mapped via hydrogen deuterium exchange–mass spectrometry. The data obtained reveal a new role for this GBS polypeptide at the interface between the innate and adaptive immune responses, adding a new member to the growing list of virulence factors secreted by gram-positive pathogens that incorporate multiple immunomodulatory functions.—Giussani, S., Pietrocola, G., Donnarumma, D., Norais, N., Speziale, P., Fabbrini, M., Margarit, I. The Streptococcus agalactiae complement interfering protein combines multiple complement-inhibitory mechanisms by interacting with both C4 and C3 ligands.
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Affiliation(s)
- Stefania Giussani
- GlaxoSmithKline (GSK), Siena, Italy; and.,Unit of Biochemistry, Molecular Medicine Department, University of Pavia, Pavia, Italy
| | - Giampiero Pietrocola
- Unit of Biochemistry, Molecular Medicine Department, University of Pavia, Pavia, Italy
| | | | | | - Pietro Speziale
- Unit of Biochemistry, Molecular Medicine Department, University of Pavia, Pavia, Italy
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57
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Korir ML, Flaherty RA, Rogers LM, Gaddy JA, Aronoff DM, Manning SD. Investigation of the Role That NADH Peroxidase Plays in Oxidative Stress Survival in Group B Streptococcus. Front Microbiol 2018; 9:2786. [PMID: 30515142 PMCID: PMC6255910 DOI: 10.3389/fmicb.2018.02786] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 10/30/2018] [Indexed: 02/02/2023] Open
Abstract
Macrophages play an important role in defending the host against infections by engulfing pathogens and containing them inside the phagosome, which consists of a harsh microbicidal environment. However, many pathogens have developed mechanisms to survive inside macrophages despite this challenge. Group B Streptococcus (GBS), a leading cause of sepsis and meningitis in neonates, is one such pathogen that survives inside macrophages by withstanding phagosomal stress. Although a few key intracellular survival factors have been identified, the mechanisms by which GBS detoxifies the phagosome are poorly defined. Transcriptional analysis during survival inside macrophages revealed strong upregulation of a putative NADH peroxidase (npx) at 1 and 24 h post-infection. A deletion mutant of npx (Δnpx) was more susceptible to killing by a complex in vitro model of multiple phagosomal biochemical/oxidant stressors or by hydrogen peroxide alone. Moreover, compared to an isogenic wild type GBS strain, the Δnpx strain demonstrated impaired survival inside human macrophages and a reduced capacity to blunt macrophage reactive oxygen species (ROS) production. It is therefore likely that Npx plays a role in survival against ROS production in the macrophage. A more thorough understanding of how GBS evades the immune system through survival inside macrophages will aid in development of new therapeutic measures.
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Affiliation(s)
- Michelle L Korir
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Rebecca A Flaherty
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Lisa M Rogers
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Jennifer A Gaddy
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.,Tennessee Valley Healthcare Systems, Department of Veterans Affairs, Nashville, TN, United States.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - David M Aronoff
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States.,Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Shannon D Manning
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
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58
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Tavares GC, Carvalho AF, Pereira FL, Rezende CP, Azevedo VAC, Leal CAG, Figueiredo HCP. Transcriptome and Proteome of Fish-Pathogenic Streptococcus agalactiae Are Modulated by Temperature. Front Microbiol 2018; 9:2639. [PMID: 30450092 PMCID: PMC6224512 DOI: 10.3389/fmicb.2018.02639] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 10/16/2018] [Indexed: 12/23/2022] Open
Abstract
Streptococcus agalactiae is one of the most important pathogens associated with streptococcosis outbreaks in Nile tilapia farms worldwide. High water temperature (above 27°C) has been described as a predisposing factor for the disease in fish. At low temperatures (below 25°C), fish mortalities are not usually observed in farms. Temperature variation can modulate the expression of genes and proteins involved in metabolism, adaptation, and bacterial pathogenicity, thus increasing or decreasing the ability to infect the host. This study aimed to evaluate the transcriptome and proteome of a fish-pathogenic S. agalactiae strain SA53 subjected to in vitro growth at different temperatures using a microarray and label-free shotgun LC-HDMSE approach. Biological triplicates of isolates were cultured in BHIT broth at 22 or 32°C for RNA and protein isolation and submitted for transcriptomic and proteomic analyses. In total, 1,730 transcripts were identified in SA53, with 107 genes being differentially expressed between the temperatures evaluated. A higher number of genes related to metabolism, mainly from the phosphotransferase system (PTS) and ATP-binding cassette (ABC) transport system, were upregulated at 32°C. In the proteome analysis, 1,046 proteins were identified in SA53, of which 81 were differentially regulated between 22 and 32°C. Proteins involved in defense mechanisms, lipid transport and metabolism, and nucleotide transport and metabolism were upregulated at 32°C. A higher number of interactions were observed in proteins involved in nucleotide transport and metabolism. We observed a low correlation between the transcriptome and proteome datasets. Our study indicates that the transcriptome and proteome of a fish-adapted S. agalactiae strain are modulated by temperature, particularly showing differential expression of genes/proteins involved in metabolism, virulence factors, and adaptation.
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Affiliation(s)
- Guilherme C Tavares
- AQUACEN-National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Alex F Carvalho
- AQUACEN-National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Felipe L Pereira
- AQUACEN-National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Cristiana P Rezende
- AQUACEN-National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Vasco A C Azevedo
- LGCM-Laboratory of Cellular and Molecular Genetics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Carlos A G Leal
- AQUACEN-National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Henrique C P Figueiredo
- AQUACEN-National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, Brazil
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59
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De Gaetano GV, Pietrocola G, Romeo L, Galbo R, Lentini G, Giardina M, Biondo C, Midiri A, Mancuso G, Venza M, Venza I, Firon A, Trieu-Cuot P, Teti G, Speziale P, Beninati C. The Streptococcus agalactiae cell wall-anchored protein PbsP mediates adhesion to and invasion of epithelial cells by exploiting the host vitronectin/α v integrin axis. Mol Microbiol 2018; 110:82-94. [PMID: 30030946 DOI: 10.1111/mmi.14084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2018] [Indexed: 01/02/2023]
Abstract
Binding of microbial pathogens to host vitronectin (Vtn) is a common theme in the pathogenesis of invasive infections. In this study, we characterized the role of Vtn in the invasion of mucosal epithelial cells by Streptococcus agalactiae (i.e. group B streptococcus or GBS), a frequent human pathogen. Moreover, we identified PbsP, a previously described plasminogen-binding protein of GBS, as a dual adhesin that can also interact with human Vtn through its streptococcal surface repeat (SSURE) domains. Deletion of the pbsP gene decreases both bacterial adhesion to Vtn-coated inert surfaces and the ability of GBS to interact with epithelial cells. Bacterial adherence to and invasion of epithelial cells were either inhibited or enhanced by cell pretreatment with, respectively, anti-Vtn antibodies or Vtn, confirming the role of Vtn as a GBS ligand on host cells. Finally, antibodies directed against the integrin αv subunit inhibited Vtn-dependent cell invasion by GBS. Collectively, these results indicate that Vtn acts as a bridge between the SSURE domains of PbsP on the GBS surface and host integrins to promote bacterial invasion of epithelial cells. Therefore, inhibition of interactions between PbsP and extracellular matrix components could represent a viable strategy to prevent colonization and invasive disease by GBS.
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Affiliation(s)
- Giuseppe Valerio De Gaetano
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Giampiero Pietrocola
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Letizia Romeo
- IRCCS Centro Neurolesi Bonino Pulejo, Messina, Italy
| | - Roberta Galbo
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Germana Lentini
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Miriam Giardina
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Carmelo Biondo
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Angelina Midiri
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Giuseppe Mancuso
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Mario Venza
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Isabella Venza
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Arnaud Firon
- Institut Pasteur, Unite de Biologie des Bacteriés Pathogènes a Gram positif, CNRS ERL6002, 75015, Paris, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unite de Biologie des Bacteriés Pathogènes a Gram positif, CNRS ERL6002, 75015, Paris, France
| | - Giuseppe Teti
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy.,Department of Industrial and Information Engineering, University of Pavia, Pavia, Italy
| | - Concetta Beninati
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy.,Scylla Biotech Srl, Messina, Italy
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60
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Weckel A, Ahamada D, Bellais S, Méhats C, Plainvert C, Longo M, Poyart C, Fouet A. The N-terminal domain of the R28 protein promotes emm28 group A Streptococcus adhesion to host cells via direct binding to three integrins. J Biol Chem 2018; 293:16006-16018. [PMID: 30150299 DOI: 10.1074/jbc.ra118.004134] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/20/2018] [Indexed: 01/07/2023] Open
Abstract
Group A Streptococcus (GAS) is a human-specific pathogen responsible for a wide range of diseases, ranging from superficial to life-threatening invasive infections, including endometritis, and autoimmune sequelae. GAS strains express a vast repertoire of virulence factors that varies depending on the strain genotype, and many adhesin proteins that enable GAS to adhere to host cells are restricted to some genotypes. GAS emm28 is the third most prevalent genotype in invasive infections in France and is associated with gyneco-obstetrical infections. emm28 strains harbor R28, a cell wall-anchored surface protein that has previously been reported to promote adhesion to cervical epithelial cells. Here, using cellular and biochemical approaches, we sought to determine whether R28 supports adhesion also to other cells and to characterize its cognate receptor. We show that through its N-terminal domain, R28Nt, R28 promotes bacterial adhesion to both endometrial-epithelial and endometrial-stromal cells. R28Nt was further subdivided into two domains, and we found that both are involved in cell binding. R28Nt and both subdomains interacted directly with the laminin-binding α3β1, α6β1, and α6β4 integrins; interestingly, these bindings events did not require divalent cations. R28 is the first GAS adhesin reported to bind directly to integrins that are expressed in most epithelial cells. Finally, R28Nt also promoted binding to keratinocytes and pulmonary epithelial cells, suggesting that it may be involved in supporting the prevalence in invasive infections of the emm28 genotype.
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Affiliation(s)
- Antonin Weckel
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Dorian Ahamada
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Samuel Bellais
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Céline Méhats
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Céline Plainvert
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and.,the Centre National de Référence des Streptocoques and.,the Hôpitaux Universitaires Paris Centre, Institut Cochin, Assistance Publique Hôpitaux de Paris, 75014 Paris, France
| | - Magalie Longo
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Claire Poyart
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and.,the Centre National de Référence des Streptocoques and.,the Hôpitaux Universitaires Paris Centre, Institut Cochin, Assistance Publique Hôpitaux de Paris, 75014 Paris, France
| | - Agnès Fouet
- From the INSERM U1016, Institut Cochin, .,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and.,the Centre National de Référence des Streptocoques and
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61
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Olivares M, Schüppel V, Hassan AM, Beaumont M, Neyrinck AM, Bindels LB, Benítez-Páez A, Sanz Y, Haller D, Holzer P, Delzenne NM. The Potential Role of the Dipeptidyl Peptidase-4-Like Activity From the Gut Microbiota on the Host Health. Front Microbiol 2018; 9:1900. [PMID: 30186247 PMCID: PMC6113382 DOI: 10.3389/fmicb.2018.01900] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/27/2018] [Indexed: 12/16/2022] Open
Abstract
The Dipeptidyl peptidase-4 (DPP-4) activity influences metabolic, behavioral and intestinal disorders through the cleavage of key hormones and peptides. Some studies describe the existence of human DPP-4 homologs in commensal bacteria, for instance in Prevotella or Lactobacillus. However, the role of the gut microbiota as a source of DPP-4-like activity has never been investigated. Through the comparison of the DPP-4 activity in the cecal content of germ-free mice (GFM) and gnotobiotic mice colonized with the gut microbiota of a healthy subject, we bring the proof of concept that a significant DPP-4-like activity occurs in the microbiota. By analyzing the existing literature, we propose that DPP-4-like activity encoded by the intestinal microbiome could constitute a novel mechanism to modulate protein digestion as well as host metabolism and behavior.
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Affiliation(s)
- Marta Olivares
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Valentina Schüppel
- ZIEL Institute for Food and Health, Technical University of Munich, Freising-Weihenstephan, Germany.,Chair of Nutrition and Immunology, Technical University of Munich, Freising-Weihenstephan, Germany
| | - Ahmed M Hassan
- Research Unit of Translational Neurogastroenterology, Pharmacology Section, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Martin Beaumont
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Audrey M Neyrinck
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Laure B Bindels
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Alfonso Benítez-Páez
- Microbial Ecology, Nutrition and Health Research Unit, Institute of Agrochemistry and Food Technology, Spanish National Research Council (IATA-CSIC), Valencia, Spain
| | - Yolanda Sanz
- Microbial Ecology, Nutrition and Health Research Unit, Institute of Agrochemistry and Food Technology, Spanish National Research Council (IATA-CSIC), Valencia, Spain
| | - Dirk Haller
- ZIEL Institute for Food and Health, Technical University of Munich, Freising-Weihenstephan, Germany.,Chair of Nutrition and Immunology, Technical University of Munich, Freising-Weihenstephan, Germany
| | - Peter Holzer
- Research Unit of Translational Neurogastroenterology, Pharmacology Section, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Nathalie M Delzenne
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
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62
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Wolf IR, Paschoal AR, Quiroga C, Domingues DS, de Souza RF, Pretto-Giordano LG, Vilas-Boas LA. Functional annotation and distribution overview of RNA families in 27 Streptococcus agalactiae genomes. BMC Genomics 2018; 19:556. [PMID: 30055586 PMCID: PMC6064168 DOI: 10.1186/s12864-018-4951-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/22/2018] [Indexed: 01/08/2023] Open
Abstract
Background Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a Gram-positive bacterium that colonizes the gastrointestinal and genitourinary tract of humans. This bacterium has also been isolated from various animals, such as fish and cattle. Non-coding RNAs (ncRNAs) can act as regulators of gene expression in bacteria, such as Streptococcus pneumoniae and Streptococcus pyogenes. However, little is known about the genomic distribution of ncRNAs and RNA families in S. agalactiae. Results Comparative genome analysis of 27 S. agalactiae strains showed more than 5 thousand genomic regions identified and classified as Core, Exclusive, and Shared genome sequences. We identified 27 to 89 RNA families per genome distributed over these regions, from these, 25 were in Core regions while Shared and Exclusive regions showed variations amongst strains. We propose that the amount and type of ncRNA present in each genome can provide a pattern to contribute in the identification of the clonal types. Conclusions The identification of RNA families provides an insight over ncRNAs, sRNAs and ribozymes function, that can be further explored as targets for antibiotic development or studied in gene regulation of cellular processes. RNA families could be considered as markers to determine infection capabilities of different strains. Lastly, pan-genome analysis of GBS including the full range of functional transcripts provides a broader approach in the understanding of this pathogen. Electronic supplementary material The online version of this article (10.1186/s12864-018-4951-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ivan Rodrigo Wolf
- Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, Brazil.
| | - Alexandre Rossi Paschoal
- Universidade Tecnológica Federal do Paraná, Campus Cornélio Procópio, Cornélio Procópio, Paraná, Brazil.
| | - Cecilia Quiroga
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPAM), Facultad de Medicina, Buenos Aires, Argentina
| | - Douglas Silva Domingues
- Departamento de Botânica, Instituto de Biociências de Rio Claro, Universidade Estadual Paulista Júlio de Mesquita Filho, Rio Claro, São Paulo, Brazil
| | - Rogério Fernandes de Souza
- Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, Brazil
| | | | - Laurival Antonio Vilas-Boas
- Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, Brazil
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63
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Type 2 NADH Dehydrogenase Is the Only Point of Entry for Electrons into the Streptococcus agalactiae Respiratory Chain and Is a Potential Drug Target. mBio 2018; 9:mBio.01034-18. [PMID: 29970468 PMCID: PMC6030563 DOI: 10.1128/mbio.01034-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The opportunistic pathogen Streptococcus agalactiae is the major cause of meningitis and sepsis in a newborn’s first week, as well as a considerable cause of pneumonia, urinary tract infections, and sepsis in immunocompromised adults. This pathogen respires aerobically if heme and quinone are available in the environment, and a functional respiratory chain is required for full virulence. Remarkably, it is shown here that the entire respiratory chain of S. agalactiae consists of only two enzymes, a type 2 NADH dehydrogenase (NDH-2) and a cytochrome bd oxygen reductase. There are no respiratory dehydrogenases other than NDH-2 to feed electrons into the respiratory chain, and there is only one respiratory oxygen reductase to reduce oxygen to water. Although S. agalactiae grows well in vitro by fermentative metabolism, it is shown here that the absence of NDH-2 results in attenuated virulence, as observed by reduced colonization in heart and kidney in a mouse model of systemic infection. The lack of NDH-2 in mammalian mitochondria and its important role for virulence suggest this enzyme may be a potential drug target. For this reason, in this study, S. agalactiae NDH-2 was purified and biochemically characterized, and the isolated enzyme was used to screen for inhibitors from libraries of FDA-approved drugs. Zafirlukast was identified to successfully inhibit both NDH-2 activity and aerobic respiration in intact cells. This compound may be useful as a laboratory tool to inhibit respiration in S. agalactiae and, since it has few side effects, it might be considered a lead compound for therapeutics development. S. agalactiae is part of the human intestinal microbiota and is present in the vagina of ~30% of healthy women. Although a commensal, it is also the leading cause of septicemia and meningitis in neonates and immunocompromised adults. This organism can aerobically respire, but only using external sources of heme and quinone, required to have a functional electron transport chain. Although bacteria usually have a branched respiratory chain with multiple dehydrogenases and terminal oxygen reductases, here we establish that S. agalactiae utilizes only one type 2 NADH dehydrogenase (NDH-2) and one cytochrome bd oxygen reductase to perform respiration. NADH-dependent respiration plays a critical role in the pathogen in maintaining NADH/NAD+ redox balance in the cell, optimizing ATP production, and tolerating oxygen. In summary, we demonstrate the essential role of NDH-2 in respiration and its contribution to S. agalactiae virulence and propose it as a potential drug target.
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Characterization of a Two-Component System Transcriptional Regulator, LtdR, That Impacts Group B Streptococcal Colonization and Disease. Infect Immun 2018; 86:IAI.00822-17. [PMID: 29685987 DOI: 10.1128/iai.00822-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 04/18/2018] [Indexed: 12/29/2022] Open
Abstract
Streptococcus agalactiae (group B Streptococcus [GBS]) is often a commensal bacterium that colonizes healthy adults asymptomatically and is a frequent inhabitant of the vaginal tract in women. However, in immunocompromised individuals, particularly the newborn, GBS may transition to an invasive pathogen and cause serious disease. Despite the use of the currently recommended intrapartum antibiotic prophylaxis for GBS-positive mothers, GBS remains a leading cause of neonatal septicemia and meningitis. To adapt to the various host environments encountered during its disease cycle, GBS possesses multiple two-component regulatory systems (TCSs). Here we investigated the contribution of a transcriptional regulator containing a LytTR domain, LtdR, to GBS pathogenesis. Disruption of the ltdR gene in the GBS chromosome resulted in a significant increase in bacterial invasion into human cerebral microvascular endothelial cells (hCMEC) in vitro as well as the greater penetration of the blood-brain barrier (BBB) and the development of meningitis in vivo Correspondingly, infection of hCMEC with the ΔltdR mutant resulted in increased secretion of the proinflammatory cytokines interleukin-8 (IL-8), CXCL-1, and IL-6. Further, using a mouse model of GBS vaginal colonization, we observed that the ΔltdR mutant was cleared more readily from the vaginal tract and also that infection with the ΔltdR mutant resulted in increased cytokine production from human vaginal epithelial cells. RNA sequencing revealed global transcriptional differences between the ΔltdR mutant and the parental wild-type GBS strain. These results suggest that LtdR regulates many bacterial processes that can influence GBS-host interactions to promote both bacterial persistence and disease progression.
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65
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Devaux L, Sleiman D, Mazzuoli MV, Gominet M, Lanotte P, Trieu-Cuot P, Kaminski PA, Firon A. Cyclic di-AMP regulation of osmotic homeostasis is essential in Group B Streptococcus. PLoS Genet 2018; 14:e1007342. [PMID: 29659565 PMCID: PMC5919688 DOI: 10.1371/journal.pgen.1007342] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/26/2018] [Accepted: 03/28/2018] [Indexed: 02/03/2023] Open
Abstract
Cyclic nucleotides are universally used as secondary messengers to control cellular physiology. Among these signalling molecules, cyclic di-adenosine monophosphate (c-di-AMP) is a specific bacterial second messenger recognized by host cells during infections and its synthesis is assumed to be necessary for bacterial growth by controlling a conserved and essential cellular function. In this study, we sought to identify the main c-di-AMP dependent pathway in Streptococcus agalactiae, the etiological agent of neonatal septicaemia and meningitis. By conditionally inactivating dacA, the only diadenyate cyclase gene, we confirm that c-di-AMP synthesis is essential in standard growth conditions. However, c-di-AMP synthesis becomes rapidly dispensable due to the accumulation of compensatory mutations. We identified several mutations restoring the viability of a ΔdacA mutant, in particular a loss-of-function mutation in the osmoprotectant transporter BusAB. Identification of c-di-AMP binding proteins revealed a conserved set of potassium and osmolyte transporters, as well as the BusR transcriptional factor. We showed that BusR negatively regulates busAB transcription by direct binding to the busAB promoter. Loss of BusR repression leads to a toxic busAB expression in absence of c-di-AMP if osmoprotectants, such as glycine betaine, are present in the medium. In contrast, deletion of the gdpP c-di-AMP phosphodiesterase leads to hyperosmotic susceptibility, a phenotype dependent on a functional BusR. Taken together, we demonstrate that c-di-AMP is essential for osmotic homeostasis and that the predominant mechanism is dependent on the c-di-AMP binding transcriptional factor BusR. The regulation of osmotic homeostasis is likely the conserved and essential function of c-di-AMP, but each species has evolved specific c-di-AMP mechanisms of osmoregulation to adapt to its environment. Nucleotide-based second messengers play central functions in bacterial physiology and host-pathogen interactions. Among these signalling nucleotides, cyclic-di-AMP (c-di-AMP) synthesis was originally assumed to be essential for bacterial growth. In this study, we confirmed that the only di-adenylate cyclase enzyme in the opportunistic pathogen Streptococcus agalactiae is essential in standard growth conditions. However, c-di-AMP synthesis becomes rapidly dispensable by accumulating spontaneous mutations in genes involved in osmotic regulation. We identified that c-di-AMP binds directly to four proteins necessary to maintain osmotic homeostasis, including three osmolyte transporters and the BusR transcriptional factor. We demonstrated that BusR negatively controls the expression of the busAB operon and that it is the main component leading to growth inhibition in the absence of c-di-AMP synthesis if osmoprotectants are present in the environment. Overall, c-di-AMP is essential to maintain osmotic homeostasis by coordinating osmolyte uptake and thus bacteria have developed specific mechanisms to keep c-di-AMP as the central regulator of osmotic homeostasis.
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Affiliation(s)
- Laura Devaux
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Dona Sleiman
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Maria-Vittoria Mazzuoli
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Myriam Gominet
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Philippe Lanotte
- Université de Tours, Infectiologie et Santé Publique, Bactéries et Risque Materno-Fœtal, INRA UMR1282, Tours France
- Hôpital Bretonneau, Centre Hospitalier Régional et Universitaire de Tours, Service de Bactériologie-Virologie, Tours France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Pierre-Alexandre Kaminski
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Arnaud Firon
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- * E-mail:
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Sekyere JO, Asante J. Emerging mechanisms of antimicrobial resistance in bacteria and fungi: advances in the era of genomics. Future Microbiol 2018; 13:241-262. [PMID: 29319341 DOI: 10.2217/fmb-2017-0172] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Bacteria and fungi continue to develop new ways to adapt and survive the lethal or biostatic effects of antimicrobials through myriad mechanisms. Novel antibiotic resistance genes such as lsa(C), erm(44), VCC-1, mcr-1, mcr-2, mcr-3, mcr-4, bla KLUC-3 and bla KLUC-4 were discovered through comparative genomics and further functional studies. As well, mutations in genes that hitherto were unknown to confer resistance to antimicrobials, such as trm, PP2C, rpsJ, HSC82, FKS2 and Rv2887, were shown by genomics and transcomplementation assays to mediate antimicrobial resistance in Acinetobacter baumannii, Staphylococcus aureus, Enterococcus faecium, Saccharomyces cerevisae, Candida glabrata and Mycobacterium tuberculosis, respectively. Thus, genomics, transcriptomics and metagenomics, coupled with functional studies are the future of antimicrobial resistance research and novel drug discovery or design.
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Affiliation(s)
- John Osei Sekyere
- Faculty of Pharmacy & Pharmaceutical Sciences, Kwame Nkrumah University of Science & Technology, Kumasi, Ghana
| | - Jonathan Asante
- Faculty of Pharmacy & Pharmaceutical Sciences, Kwame Nkrumah University of Science & Technology, Kumasi, Ghana
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67
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Patras KA, Nizet V. Group B Streptococcal Maternal Colonization and Neonatal Disease: Molecular Mechanisms and Preventative Approaches. Front Pediatr 2018; 6:27. [PMID: 29520354 PMCID: PMC5827363 DOI: 10.3389/fped.2018.00027] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Group B Streptococcus (GBS) colonizes the gastrointestinal and vaginal epithelium of a significant percentage of healthy women, with potential for ascending intrauterine infection or transmission during parturition, creating a risk of serious disease in the vulnerable newborn. This review highlights new insights on the bacterial virulence determinants, host immune responses, and microbiome interactions that underpin GBS vaginal colonization, the proximal step in newborn infectious disease pathogenesis. From the pathogen perspective, the function GBS adhesins and biofilms, β-hemolysin/cytolysin toxin, immune resistance factors, sialic acid mimicry, and two-component transcriptional regulatory systems are reviewed. From the host standpoint, pathogen recognition, cytokine responses, and the vaginal mucosal and placental immunity to the pathogen are detailed. Finally, the rationale, efficacy, and potential unintended consequences of current universal recommended intrapartum antibiotic prophylaxis are considered, with updates on new developments toward a GBS vaccine or alternative approaches to reducing vaginal colonization.
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Affiliation(s)
- Kathryn A Patras
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
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Lorenzo-Diaz F, Fernández-Lopez C, Douarre PE, Baez-Ortega A, Flores C, Glaser P, Espinosa M. Streptococcal group B integrative and mobilizable element IMESag-rpsI encodes a functional relaxase involved in its transfer. Open Biol 2017; 6:rsob.160084. [PMID: 27707895 PMCID: PMC5090054 DOI: 10.1098/rsob.160084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 09/12/2016] [Indexed: 12/13/2022] Open
Abstract
Streptococcus agalactiae or Group B Streptococcus (GBS) are opportunistic bacteria that can cause lethal sepsis in children and immuno-compromised patients. Their genome is a reservoir of mobile genetic elements that can be horizontally transferred. Among them, integrative and conjugative elements (ICEs) and the smaller integrative and mobilizable elements (IMEs) primarily reside in the bacterial chromosome, yet have the ability to be transferred between cells by conjugation. ICEs and IMEs are therefore a source of genetic variability that participates in the spread of antibiotic resistance. Although IMEs seem to be the most prevalent class of elements transferable by conjugation, they are poorly known. Here, we have studied a GBS-IME, termed IMESag-rpsI, which is widely distributed in GBS despite not carrying any apparent virulence trait. Analyses of 240 whole genomes showed that IMESag-rpsI is present in approximately 47% of the genomes, has a roughly constant size (approx. 9 kb) and is always integrated at a single location, the 3′-end of the gene encoding the ribosomal protein S9 (rpsI). Based on their genetic variation, several IMESag-rpsI types were defined (A–J) and classified in clonal complexes (CCs). CC1 was the most populated by IMESag-rpsI (more than 95%), mostly of type-A (71%). One CC1 strain (S. agalactiae HRC) was deep-sequenced to understand the rationale underlying type-A IMESag-rpsI enrichment in GBS. Thirteen open reading frames were identified, one of them encoding a protein (MobSag) belonging to the broadly distributed family of relaxases MOBV1. Protein MobSag was purified and, by a newly developed method, shown to cleave DNA at a specific dinucleotide. The S. agalactiae HRC-IMESag-rpsI is able to excise from the chromosome, as shown by the presence of circular intermediates, and it harbours a fully functional mobilization module. Further, the mobSag gene encoded by this mobile element is able to promote plasmid transfer among pneumococcal strains, suggesting that MobSag facilitates the spread of IMESag-rpsI and that this spread would explain the presence of the same IMESag-rpsI type in GBS strains belonging to different CCs.
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Affiliation(s)
- Fabian Lorenzo-Diaz
- Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias, Universidad de La Laguna, Av. Astrofísico Francisco Sánchez s/n, 38071 Santa Cruz de Tenerife, Spain Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | | | - Pierre-Emmanuel Douarre
- Institut Pasteur, Unité Ecologie et Evolution de la Résistance aux Antibiotiques, Paris CNRS UMR3525, France
| | - Adrian Baez-Ortega
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, UK
| | - Carlos Flores
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Philippe Glaser
- Institut Pasteur, Unité Ecologie et Evolution de la Résistance aux Antibiotiques, Paris CNRS UMR3525, France
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Intrinsic Maturational Neonatal Immune Deficiencies and Susceptibility to Group B Streptococcus Infection. Clin Microbiol Rev 2017; 30:973-989. [PMID: 28814408 DOI: 10.1128/cmr.00019-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although a normal member of the gastrointestinal and vaginal microbiota, group B Streptococcus (GBS) can also occasionally be the cause of highly invasive neonatal disease and is an emerging pathogen in both elderly and immunocompromised adults. Neonatal GBS infections are typically transmitted from mother to baby either in utero or during passage through the birth canal and can lead to pneumonia, sepsis, and meningitis within the first few months of life. Compared to the adult immune system, the neonatal immune system has a number of deficiencies, making neonates more susceptible to infection. Recognition of GBS by the host immune system triggers an inflammatory response to clear the pathogen. However, GBS has developed several mechanisms to evade the host immune response. A comprehensive understanding of this interplay between GBS and the host immune system will aid in the development of new preventative measures and therapeutics.
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70
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Zhou K, Xie L, Han L, Guo X, Wang Y, Sun J. ICE Sag37, a Novel Integrative and Conjugative Element Carrying Antimicrobial Resistance Genes and Potential Virulence Factors in Streptococcus agalactiae. Front Microbiol 2017; 8:1921. [PMID: 29051752 PMCID: PMC5633684 DOI: 10.3389/fmicb.2017.01921] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/21/2017] [Indexed: 11/13/2022] Open
Abstract
ICESag37, a novel integrative and conjugative element carrying multidrug resistance and potential virulence factors, was characterized in a clinical isolate of Streptococcus agalactiae. Two clinical strains of S. agalactiae, Sag37 and Sag158, were isolated from blood samples of new-borns with bacteremia. Sag37 was highly resistant to erythromycin and tetracycline, and susceptible to levofloxacin and penicillin, while Sag158 was resistant to tetracycline and levofloxacin, and susceptible to erythromycin. Transfer experiments were performed and selection was carried out with suitable antibiotic concentrations. Through mating experiments, the erythromycin resistance gene was found to be transferable from Sag37 to Sag158. SmaI-PFGE revealed a new SmaI fragment, confirming the transfer of the fragment containing the erythromycin resistance gene. Whole genome sequencing and sequence analysis revealed a mobile element, ICESag37, which was characterized using several molecular methods and in silico analyses. ICESag37 was excised to generate a covalent circular intermediate, which was transferable to S. agalactiae. Inverse PCR was performed to detect the circular form. A serine family integrase mediated its chromosomal integration into rumA, which is a known hotspot for the integration of streptococcal ICEs. The integration site was confirmed using PCR. ICESag37 carried genes for resistance to multiple antibiotics, including erythromycin [erm(B)], tetracycline [tet(O)], and aminoglycosides [aadE, aphA, and ant(6)]. Potential virulence factors, including a two-component signal transduction system (nisK/nisR), were also observed in ICESag37. S1-PFGE analysis ruled out the existence of plasmids. ICESag37 is the first ICESa2603 family-like element identified in S. agalactiae carrying both resistance and potential virulence determinants. It might act as a vehicle for the dissemination of multidrug resistance and pathogenicity among S. agalactiae.
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Affiliation(s)
- Kaixin Zhou
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lianyan Xie
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lizhong Han
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaokui Guo
- Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yong Wang
- Department of Laboratory Medicine, Shandong Provincial Hospital, Shandong University, Jinan, China
| | - Jingyong Sun
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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71
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Hu WT, Guo WL, Meng AY, Sun Y, Wang SF, Xie ZY, Zhou YC, He C. A metabolomic investigation into the effects of temperature on Streptococcus agalactiae from Nile tilapia (Oreochromis niloticus) based on UPLC-MS/MS. Vet Microbiol 2017; 210:174-182. [PMID: 29103689 DOI: 10.1016/j.vetmic.2017.09.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/16/2017] [Accepted: 09/19/2017] [Indexed: 12/22/2022]
Abstract
Streptococcosis caused by Streptococcus agalactiae is one of the most serious diseases in farmed tilapia, and temperature is one of the most important environmental factors related to its outbreak. To elucidate the influence of temperature variation on the pathogen from a metabolic perspective, the global metabolomics of 2 pathogenic strains of S. agalactiae from sick tilapia were analyzed at 35°C and 25°C using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with pattern recognition approaches and pathway analysis. The result showed that the metabolic status of S. agalactiae was extensively affected by its culture temperature. Based on the results of metabolites contributing to these differences, a large number of nucleotides and their ramifications were markedly elevated at 35°C. Various energy substances, components of the cell wall and substances associated with stress regulation such as glyceraldehyde 3-phosphate, pyroglutamic acid, glutamate, d-Alanyl-d-alanine, glycerophosphocholine, dephospho-CoA, and oxidized glutathione increased when the strains were cultured at 35°C. Additionally, a general decrease in various precursors of capsule, antigen, and virulence protein formation were detected including mannose, maltotriose, N-acetyl-d-glucosamine 6-phosphate, uracil, proline, and citrulline. These metabolic changes indicated that metabolic activity decreased, while adaptive ability to environment and pathogenicity to host increased at high temperature. This study is the first to determine the metabolomic responses of S. agalactiae to temperature, and the results are useful to reveal its pathogenic mechanism and find effective disease control.
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Affiliation(s)
- Wen-Ting Hu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China
| | - Wei-Liang Guo
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China
| | - Ai-Yun Meng
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China
| | - Yun Sun
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China
| | - Shi-Feng Wang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China
| | - Zhen-Yu Xie
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China
| | - Yong-Can Zhou
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China.
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, 58 Renmin Rd, Haikou, 570228 PR China.
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72
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Shabayek S, Spellerberg B. Acid Stress Response Mechanisms of Group B Streptococci. Front Cell Infect Microbiol 2017; 7:395. [PMID: 28936424 PMCID: PMC5594096 DOI: 10.3389/fcimb.2017.00395] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 08/23/2017] [Indexed: 12/20/2022] Open
Abstract
Group B streptococcus (GBS) is a leading cause of neonatal mortality and morbidity in the United States and Europe. It is part of the vaginal microbiota in up to 30% of pregnant women and can be passed on to the newborn through perinatal transmission. GBS has the ability to survive in multiple different host niches. The pathophysiology of this bacterium reveals an outstanding ability to withstand varying pH fluctuations of the surrounding environments inside the human host. GBS host pathogen interations include colonization of the acidic vaginal mucosa, invasion of the neutral human blood or amniotic fluid, breaching of the blood brain barrier as well as survival within the acidic phagolysosomal compartment of macrophages. However, investigations on GBS responses to acid stress are limited. Technologies, such as whole genome sequencing, genome-wide transcription and proteome mapping facilitate large scale identification of genes and proteins. Mechanisms enabling GBS to cope with acid stress have mainly been studied through these techniques and are summarized in the current review
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Affiliation(s)
- Sarah Shabayek
- Institute of Medical Microbiology and Hygiene, University of UlmUlm, Germany.,Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal UniversityIsmailia, Egypt
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University of UlmUlm, Germany
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73
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Andrade WA, Firon A, Schmidt T, Hornung V, Fitzgerald KA, Kurt-Jones EA, Trieu-Cuot P, Golenbock DT, Kaminski PA. Group B Streptococcus Degrades Cyclic-di-AMP to Modulate STING-Dependent Type I Interferon Production. Cell Host Microbe 2017; 20:49-59. [PMID: 27414497 DOI: 10.1016/j.chom.2016.06.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 04/29/2016] [Accepted: 06/06/2016] [Indexed: 11/16/2022]
Abstract
Induction of type I interferon (IFN) in response to microbial pathogens depends on a conserved cGAS-STING signaling pathway. The presence of DNA in the cytoplasm activates cGAS, while STING is activated by cyclic dinucleotides (cdNs) produced by cGAS or from bacterial origins. Here, we show that Group B Streptococcus (GBS) induces IFN-β production almost exclusively through cGAS-STING-dependent recognition of bacterial DNA. However, we find that GBS expresses an ectonucleotidase, CdnP, which hydrolyzes extracellular bacterial cyclic-di-AMP. Inactivation of CdnP leads to c-di-AMP accumulation outside the bacteria and increased IFN-β production. Higher IFN-β levels in vivo increase GBS killing by the host. The IFN-β overproduction observed in the absence of CdnP is due to the cumulative effect of DNA sensing by cGAS and STING-dependent sensing of c-di-AMP. These findings describe the importance of a bacterial c-di-AMP ectonucleotidase and suggest a direct bacterial mechanism that dampens activation of the cGAS-STING axis.
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Affiliation(s)
- Warrison A Andrade
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Arnaud Firon
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, 75724 Paris, France; Centre National de la Recherche Scientifique (CNRS) ERL 3526, 75724 Paris, France
| | - Tobias Schmidt
- Institute of Molecular Medicine, Universitätsklinikum Bonn, Bonn 53127, Germany
| | - Veit Hornung
- Institute of Molecular Medicine, Universitätsklinikum Bonn, Bonn 53127, Germany
| | - Katherine A Fitzgerald
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Evelyn A Kurt-Jones
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, 75724 Paris, France; Centre National de la Recherche Scientifique (CNRS) ERL 3526, 75724 Paris, France.
| | - Douglas T Golenbock
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Pierre-Alexandre Kaminski
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, 75724 Paris, France; Centre National de la Recherche Scientifique (CNRS) ERL 3526, 75724 Paris, France
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74
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Ma Y, Hao L, Ke H, Liang Z, Ma J, Liu Z, Li Y. LuxS/AI-2 in Streptococcus agalactiae reveals a key role in acid tolerance and virulence. Res Vet Sci 2017; 115:501-507. [PMID: 28858764 DOI: 10.1016/j.rvsc.2017.07.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 07/18/2017] [Accepted: 07/26/2017] [Indexed: 12/30/2022]
Abstract
LuxS-mediated autoinducer-2 (AI-2) directly or indirectly regulates important physiologic function in a variety of bacteria. We found a luxS homologue in the genome of Streptococcus agalactiae, an important pathogen of tilapia. To investigate the relationship between luxS/AI-2 and pathogenicity for tilapia, its bioluminescent activity, acid resistance, cell adherence, virulence, and regulation of virulence gene were evaluated. Compared with the wild-type strain, the bioluminescent activity lost in the luxS mutant, its resistance to acid (pH2.8) was significantly decreased 33.8 times, and furthermore, its adherence to the NGF-2 cell line was dramatically reduced 3 times in the mutant strain. The virulence of the mutant strain was decreased in the tilapia infection model, exogenous AI-2 molecule (7.4nM) and luxS gene complementation with plasmid could complement the deficiencies of function in the luxS mutant strain. These results showed that inactivation of luxS gene caused a significant decrease of bioluminance, acid resistance, cell adhesion, virulence to tilapia and transcription levels of many virulence genes in S. agalactiae. Expression of the known stress resistance factors DnaK and GroEL, relative regulator factors CovR/CovS and virulence factor cpsE verified above results. These findings suggest that luxS may be involved in the interruption of bacterial virulence and resistance to environmental factors.
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Affiliation(s)
- Yanping Ma
- Guangdong Provincial key Laboratory of Livestock Disease Prevention, Guangdong Open Laboratory of Veterinary Public Health, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China
| | - Le Hao
- Guangdong Provincial key Laboratory of Livestock Disease Prevention, Guangdong Open Laboratory of Veterinary Public Health, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China
| | - Hao Ke
- Guangdong Provincial key Laboratory of Livestock Disease Prevention, Guangdong Open Laboratory of Veterinary Public Health, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China
| | - Zhiling Liang
- Guangdong Provincial key Laboratory of Livestock Disease Prevention, Guangdong Open Laboratory of Veterinary Public Health, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China
| | - Jiangyao Ma
- Guangdong Provincial key Laboratory of Livestock Disease Prevention, Guangdong Open Laboratory of Veterinary Public Health, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China
| | - Zhenxing Liu
- Guangdong Provincial key Laboratory of Livestock Disease Prevention, Guangdong Open Laboratory of Veterinary Public Health, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China.
| | - Yugu Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
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75
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Kuleshevich E, Ferretti J, Santos Sanches I, Balasubramanian N, Spellerberg B, Efstratiou A, Kriz P, Grabovskaya K, Arjanova O, Savitcheva A, Shevchenko V, Rysev A, Suvorov A. Clinical strains of Streptococcus agalactiae carry two different variants of pathogenicity island XII. Folia Microbiol (Praha) 2017; 62:393-399. [PMID: 28315021 DOI: 10.1007/s12223-017-0509-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 02/21/2017] [Indexed: 01/12/2023]
Abstract
Streptococcus agalactiae or Group B streptococci (GBS) are a common cause of serious diseases of newborns and adults. GBS pathogenicity largely depends on genes located on the accessory genome including several pathogenicity islands (PAI). The present paper is focused on the structure and molecular epidemiological analysis of one of the GBS pathogenicity islands-the pathogenicity island PAI XII (Glaser et al. Mol Microbiol 45(6):1499-1513, 2002). This PAI was found to be composed of three different mobile genetic elements: a composite transposon (PAI-C), a genomic islet (PAI-B), and a pathogenicity island associated with gene sspB1 (PAI-A). PAI-A in GBS has a homolog--PAI-A1 with similar, but a different genetic constellation. PCR-based analysis of GBS collections from different countries revealed that a strains lineage with PAI-A is less common than PAI-A1 and was determined to be present only among the strains obtained from Russia. Our results suggest that PAI-A and PAI-A1 have the same progenitor, which evolved independently and appeared in the GBS genome as separate genetic events. Results of this study reflect specific geographical distribution of the GBS strains with the mobile genetic element under study.
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Affiliation(s)
- Eugenia Kuleshevich
- Institute of Experimental Medicine, Pavlova Street, 12, 197376, Saint-Petersburg, Russia
| | - Joseph Ferretti
- University of Oklahoma Health Sciences Center, 1100 N Lindsay Ave, Oklahoma City, OK, 73104, USA
| | - Ilda Santos Sanches
- Research Unit on Applied Molecular Biosciences (UCIBIO@REQUIMTE). Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Natesan Balasubramanian
- Research Unit on Applied Molecular Biosciences (UCIBIO@REQUIMTE). Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | | | - Paula Kriz
- WHO Center Reference and Research on Streptococci, Srobarova, 48 10042 10, Prague, Czech Republic
| | - Kornelia Grabovskaya
- Institute of Experimental Medicine, Pavlova Street, 12, 197376, Saint-Petersburg, Russia
| | - Olga Arjanova
- D. O. Ott Research Institute of Obstetrics and Gynecology, 199034, Mendeleevskaya line, 3, Saint-Petersburg, Russia
| | - Alevtina Savitcheva
- D. O. Ott Research Institute of Obstetrics and Gynecology, 199034, Mendeleevskaya line, 3, Saint-Petersburg, Russia
| | - Valentin Shevchenko
- Institute of Experimental Medicine, Pavlova Street, 12, 197376, Saint-Petersburg, Russia
| | - Anton Rysev
- Institute of Experimental Medicine, Pavlova Street, 12, 197376, Saint-Petersburg, Russia
| | - Alexander Suvorov
- Institute of Experimental Medicine, Pavlova Street, 12, 197376, Saint-Petersburg, Russia.
- Saint-Petersburg State University, 199034, Universitetskaya emb. 7/9, Saint-Petersburg, Russia.
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76
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Gabrielsen C, Mæland JA, Lyng RV, Radtke A, Afset JE. Molecular characteristics of Streptococcus agalactiae strains deficient in alpha-like protein encoding genes. J Med Microbiol 2017; 66:26-33. [PMID: 28032541 DOI: 10.1099/jmm.0.000412] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Streptococcus agalactiae (group B streptococci, GBS) are important human and animal pathogens, which can be subdivided based on different capsular polysaccharides and surface-anchored alpha-like proteins (Alps), as well as other proteins. Nearly all GBS strains possess an Alp (Alp GBS), although Alp-negative GBS (non-Alp GBS) do occur. In this study, 10 (1.1 %) of 932 clinical human GBS tested lacked an Alp encoding gene. All 10 strains were from patients with bloodstream infection, confirming that non-Alp GBS can be highly virulent. All non-Alp GBS expressed one or more of the surface-anchored proteins R3, Z1 and Z2, while less than 10 % of unselected clinical strains express any of these proteins. In contrast to Alp GBS, all non-Alp strains tested were PCR negative for the upstream sequence of the insertion site of the Alp encoding gene of Alp GBS. Genome sequencing showed that all but one of the 10 clinical non-Alp strains and the non-Alp reference strain CNCTC 10/84 lacked a region surrounding the Alp gene commonly present in Alp GBS strains. These strains instead harboured an 849 bp region not present in the Cα prototype strain A909. We have shown that non-Alp GBS differ from Alp GBS in the region surrounding the insertion site of Alp genes of Alp GBS as well as in their content of other surface proteins and that PCR for the upstream flanking region of the Alp gene may be useful for differentiation between Alp and non-Alp GBS.
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Affiliation(s)
- Christina Gabrielsen
- Department of Medical Microbiology, St Olavs University Hospital, Trondheim, Norway
| | - Johan A Mæland
- Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Randi Valsø Lyng
- Department of Medical Microbiology, St Olavs University Hospital, Trondheim, Norway
| | - Andreas Radtke
- Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Medical Microbiology, St Olavs University Hospital, Trondheim, Norway
| | - Jan Egil Afset
- Department of Medical Microbiology, St Olavs University Hospital, Trondheim, Norway.,Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
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77
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Parker RE, Knupp D, Al Safadi R, Rosenau A, Manning SD. Contribution of the RgfD Quorum Sensing Peptide to rgf Regulation and Host Cell Association in Group B Streptococcus. Genes (Basel) 2017; 8:genes8010023. [PMID: 28067833 PMCID: PMC5295018 DOI: 10.3390/genes8010023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/29/2016] [Accepted: 01/04/2017] [Indexed: 11/16/2022] Open
Abstract
Streptococcus agalactiae (group B Streptococcus; GBS) is a common inhabitant of the genitourinary and/or gastrointestinal tract in up to 40% of healthy adults; however, this opportunistic pathogen is able to breach restrictive host barriers to cause disease and persist in harsh and changing conditions. This study sought to identify a role for quorum sensing, a form of cell to cell communication, in the regulation of the fibrinogen-binding (rgfBDAC) two-component system and the ability to associate with decidualized endometrial cells in vitro. To do this, we created a deletion in rgfD, which encodes the putative autoinducing peptide, in a GBS strain belonging to multilocus sequence type (ST)-17 and made comparisons to the wild type. Sequence variation in the rgf operon was detected in 40 clinical strains and a non-synonymous single nucleotide polymorphism was detected in rgfD in all of the ST-17 genomes that resulted in a truncation. Using qPCR, expression of rgf operon genes was significantly decreased in the ST-17 ΔrgfD mutant during exponential growth with the biggest difference (3.3-fold) occurring at higher cell densities. Association with decidualized endometrial cells was decreased 1.3-fold in the mutant relative to the wild type and rgfC expression was reduced 22-fold in ΔrgfD following exposure to the endometrial cells. Collectively, these data suggest that this putative quorum sensing molecule is important for attachment to human tissues and demonstrate a role for RgfD in GBS pathogenesis through regulation of rgfC.
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Affiliation(s)
- Robert E Parker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
| | - David Knupp
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
| | - Rim Al Safadi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
| | - Agnѐs Rosenau
- Infectiologie et Santé Publique ISP, Institut National de la Recherche Agronomique, Université de Tours, Equipe Bactéries et Risque Materno-fœtal, UMR1282 Tours, France.
| | - Shannon D Manning
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
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78
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Lee DH, Shin H, Kim S. Rapid Detection of Group B StreptococcusUsing ChromID STRB and PCR in the Pregnant Women. ANNALS OF CLINICAL MICROBIOLOGY 2017. [DOI: 10.5145/acm.2017.20.4.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Dong-Hyun Lee
- Department of Laboratory Medicine, Gyeongsang National University School of Medicine, Gyeongsang Institute of Health Sciences, Jinju, Korea
| | - Hyoshim Shin
- Department of Laboratory Medicine, Gyeongsang National University School of Medicine, Gyeongsang Institute of Health Sciences, Jinju, Korea
| | - Sunjoo Kim
- Department of Laboratory Medicine, Gyeongsang National University School of Medicine, Gyeongsang Institute of Health Sciences, Jinju, Korea
- Department of Laboratory Medicine, Changwon Gyeongsang National University Hospital, Changwon, Korea
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79
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Ruppen C, Hemphill A, Sendi P. In vitro activity of gentamicin as an adjunct to penicillin against biofilm group B Streptococcus. J Antimicrob Chemother 2016; 72:444-447. [PMID: 27999071 DOI: 10.1093/jac/dkw447] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 09/14/2016] [Accepted: 09/24/2016] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Group B Streptococcus (GBS) increasingly causes invasive disease in non-pregnant adults, particularly in elderly persons and those with underlying diseases. Combination therapy with penicillin plus gentamicin has been suggested for periprosthetic joint infection. The postulated synergism of this combination is based on experiments with planktonic bacteria. We aimed to assess the efficacy of this combination against sessile bacteria. METHODS Four different GBS strains were used. We compared results of MICs with those of minimal biofilm eradication concentrations (MBECs), applied chequerboard assays to the MBEC device and calculated the fractional inhibitory concentration index. Synergism was evaluated with time-kill assays against bacteria adherent to cement beads, using penicillin (0.048, 0.2 and 3 mg/L), gentamicin (4 and 12.5 mg/L) and a combination thereof. Results were evaluated via colony counting after sonication of beads and scanning electron microscopy. RESULTS MBEC/MIC ratios were 2000-4000 for penicillin and 1-4 for gentamicin. In chequerboard assays, synergism was observed in all four isolates. In time-kill assays, penicillin and 12.5 mg/L gentamicin showed synergism in two isolates. In the other two isolates 12.5 mg/L gentamicin alone was as efficient as the combination therapy. CONCLUSIONS These in vitro investigations show activity of 12.5 mg/L gentamicin, alone or as an adjunct to penicillin, against four strains of biofilm GBS. This concentration cannot be achieved in bone with systemic administration, but can be reached if administered locally. The combination of systemic penicillin plus local gentamicin indicates a potential application in orthopaedic-device-associated GBS infections. Studies with a larger number of strains are required to confirm our results.
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Affiliation(s)
- Corinne Ruppen
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Science, University of Bern, Bern, Switzerland
| | - Andrew Hemphill
- Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Parham Sendi
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland .,Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland
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80
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Patron K, Gilot P, Rong V, Hiron A, Mereghetti L, Camiade E. Inductors and regulatory properties of the genomic island-associatedfru2metabolic operon ofStreptococcus agalactiae. Mol Microbiol 2016; 103:678-697. [DOI: 10.1111/mmi.13581] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Kévin Patron
- Bactéries et Risque Materno-Foetal, UMR1282 Infectiologie et Santé Publique, Université François Rabelais, INRA; Tours F-37032 France
| | - Philippe Gilot
- Bactéries et Risque Materno-Foetal, UMR1282 Infectiologie et Santé Publique, Université François Rabelais, INRA; Tours F-37032 France
| | - Vanessa Rong
- Bactéries et Risque Materno-Foetal, UMR1282 Infectiologie et Santé Publique, Université François Rabelais, INRA; Tours F-37032 France
| | - Aurélia Hiron
- Bactéries et Risque Materno-Foetal, UMR1282 Infectiologie et Santé Publique, Université François Rabelais, INRA; Tours F-37032 France
| | - Laurent Mereghetti
- Bactéries et Risque Materno-Foetal, UMR1282 Infectiologie et Santé Publique, Université François Rabelais, INRA; Tours F-37032 France
- Service de Bactériologie-Virologie-Hygiène; Centre Hospitalier Universitaire de Tours; Tours F-37044 France
| | - Emilie Camiade
- Bactéries et Risque Materno-Foetal, UMR1282 Infectiologie et Santé Publique, Université François Rabelais, INRA; Tours F-37032 France
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81
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Korir ML, Laut C, Rogers LM, Plemmons JA, Aronoff DM, Manning SD. Differing mechanisms of surviving phagosomal stress among group B Streptococcus strains of varying genotypes. Virulence 2016; 8:924-937. [PMID: 27791478 DOI: 10.1080/21505594.2016.1252016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Group B Streptococcus (GBS), a leading cause of neonatal sepsis and meningitis, asymptomatically colonizes up to 30% of women and can persistently colonize even after antibiotic treatment. Previous studies have shown that GBS resides inside macrophages, but the mechanism by which it survives remains unknown. Here, we examined the ability of 4 GBS strains to survive inside macrophages and then focused on 2 strains belonging to sequence type (ST)-17 and ST-12, to examine persistence in the presence of antibiotics. A multiple stress medium was also developed using several stressors found in the phagosome to assess the ability of 30 GBS strains to withstand phagosomal stress. The ST-17 strain was more readily phagocytosed and survived intracellularly longer than the ST-12 strain, but the ST-12 strain was tolerant to ampicillin unlike the ST-17 strain. Exposure to sub-inhibitory concentrations of ampicillin and erythromycin increased the level of phagocytosis of the ST-17 strain, but had no effect on the ST-12 strain. In addition, blocking acidification of the phagosome decreased the survival of the ST-17 strain indicating a pH-dependent survival mechanism for the ST-17 strain. Congruent with the macrophage experiments, the ST-17 strain had a higher survival rate in the multiple stress medium than the ST-12 strain, and overall, serotype III isolates survived significantly better than other serotypes. These results indicate that diverse GBS strains may use differing mechanisms to persist and that serotype III strains are better able to survive specific stressors inside the phagosome relative to other serotypes.
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Affiliation(s)
- Michelle L Korir
- a Department of Microbiology and Molecular Genetics , Michigan State University , East Lansing , MI , USA
| | - Clare Laut
- a Department of Microbiology and Molecular Genetics , Michigan State University , East Lansing , MI , USA
| | - Lisa M Rogers
- b Department of Medicine , Vanderbilt University , Nashville , TN , USA
| | - Jessica A Plemmons
- a Department of Microbiology and Molecular Genetics , Michigan State University , East Lansing , MI , USA
| | - David M Aronoff
- b Department of Medicine , Vanderbilt University , Nashville , TN , USA
| | - Shannon D Manning
- a Department of Microbiology and Molecular Genetics , Michigan State University , East Lansing , MI , USA
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82
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Ruppen C, Lupo A, Decosterd L, Sendi P. Is Penicillin Plus Gentamicin Synergistic against Clinical Group B Streptococcus isolates?: An In vitro Study. Front Microbiol 2016; 7:1680. [PMID: 27818657 PMCID: PMC5073528 DOI: 10.3389/fmicb.2016.01680] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/07/2016] [Indexed: 11/23/2022] Open
Abstract
Group B Streptococcus (GBS) is increasingly causing invasive infections in non-pregnant adults. Elderly patients and those with comorbidities are at increased risk. On the basis of previous studies focusing on neonatal infections, penicillin plus gentamicin is recommended for infective endocarditis (IE) and periprosthetic joint infections (PJI) in adults. The purpose of this study was to investigate whether a synergism with penicillin and gentamicin is present in GBS isolates that caused IE and PJI. We used 5 GBS isolates, two clinical strains and three control strains, including one displaying high-level gentamicin resistance (HLGR). The results from the checkerboard and time-kill assays (TKAs) were compared. For TKAs, antibiotic concentrations for penicillin were 0.048 and 0.2 mg/L, and for gentamicin 4 mg/L or 12.5 mg/L. In the checkerboard assay, the median fractional inhibitory concentration indices (FICIs) of all isolates indicated indifference. TKAs for all isolates failed to demonstrate synergism with penicillin 0.048 or 0.2 mg/L, irrespective of gentamicin concentrations used. Rapid killing was seen with penicillin 0.048 mg/L plus either 4 mg/L or 12.5 mg/L gentamicin, from 2 h up to 8 h hours after antibiotic exposure. TKAs with penicillin 0.2 mg/L decreased the starting inoculum below the limit of quantification within 4–6 h, irrespective of the addition of gentamicin. Fast killing was seen with penicillin 0.2 mg/L plus 12.5 mg/L gentamicin within the first 2 h. Our in vitro results indicate that the addition of gentamicin to penicillin contributes to faster killing at low penicillin concentrations, but only within the first few hours. Twenty-four hours after antibiotic exposure, PEN alone was bactericidal and synergism was not seen.
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Affiliation(s)
- Corinne Ruppen
- Institute for Infectious Diseases, University of BernBern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of BernBern, Switzerland
| | - Agnese Lupo
- Institute for Infectious Diseases, University of Bern Bern, Switzerland
| | - Laurent Decosterd
- Division and Laboratory of Clinical Pharmacology, Service of Biomedicine, Department of Laboratories, Centre Hospitalier Universitaire Vaudois (CHUV) Lausanne, Switzerland
| | - Parham Sendi
- Institute for Infectious Diseases, University of BernBern, Switzerland; Department of Infectious Diseases, Bern University Hospital, University of BernBern, Switzerland
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83
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Franza T, Delavenne E, Derré-Bobillot A, Juillard V, Boulay M, Demey E, Vinh J, Lamberet G, Gaudu P. A partial metabolic pathway enables group b streptococcus to overcome quinone deficiency in a host bacterial community. Mol Microbiol 2016; 102:81-91. [PMID: 27328751 DOI: 10.1111/mmi.13447] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2016] [Indexed: 11/28/2022]
Abstract
Aerobic respiration metabolism in Group B Streptococcus (GBS) is activated by exogenous heme and menaquinone. This capacity enhances resistance of GBS to acid and oxidative stress and improves its survival. In this work, we discovered that GBS is able to respire in the presence of heme and 1,4-dihydroxy-2-naphthoic acid (DHNA). DHNA is a biosynthetic precursor of demethylmenaquinone (DMK) in many bacterial species. A GBS gene (gbs1789) encodes a homolog of the MenA 1,4-dihydroxy-2-naphthoate prenyltransferase enzyme, involved in the synthesis of demethylmenaquinone. In this study, we showed that gbs1789 is involved in the biosynthesis of long-chain demethylmenaquinones (DMK-10). The Δgbs1789 mutant cannot respire in the presence of heme and DHNA, indicating that endogenously synthesized DMKs are cofactors of the GBS respiratory chain. We also found that isoprenoid side chains from GBS DMKs are produced by the protein encoded by the gbs1783 gene, since this gene can complement an Escherichia coli ispB mutant defective for isoprenoids chain synthesis. In the gut or vaginal microbiote, where interspecies metabolite exchanges occur, this partial DMK biosynthetic pathway can be important for GBS respiration and survival in different niches.
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Affiliation(s)
- Thierry Franza
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France.
| | - Emilie Delavenne
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Aurélie Derré-Bobillot
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Vincent Juillard
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Mylène Boulay
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | | | - Joelle Vinh
- ESPCI Paris, SMBP USR3149 CNRS, Paris, F-75005, France
| | - Gilles Lamberet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Philippe Gaudu
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
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84
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Complete genome sequence of Streptococcus agalactiae strain GBS85147 serotype of type Ia isolated from human oropharynx. Stand Genomic Sci 2016; 11:39. [PMID: 27274785 PMCID: PMC4891928 DOI: 10.1186/s40793-016-0158-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 05/23/2016] [Indexed: 11/30/2022] Open
Abstract
Streptococcus agalactiae, also referred to as Group B Streptococcus, is a frequent resident of the rectovaginal tract in humans, and a major cause of neonatal infection. The pathogen can also infect adults with underlying disease, particularly the elderly and immunocompromised ones. In addition, S. agalactiae is a known fish pathogen, which compromises food safety and represents a zoonotic hazard. This study provides valuable structural, functional and evolutionary genomic information of a human S. agalactiae serotype Ia (ST-103) GBS85147 strain isolated from the oropharynx of an adult patient from Rio de Janeiro, thereby representing the first human isolate in Brazil. We used the Ion Torrent PGM platform with the 200 bp fragment library sequencing kit. The sequencing generated 578,082,183 bp, distributed among 2,973,022 reads, resulting in an approximately 246-fold mean coverage depth and was assembled using the Mira Assembler v3.9.18. The S. agalactiae strain GBS85147 comprises of a circular chromosome with a final genome length of 1,996,151 bp containing 1,915 protein-coding genes, 18 rRNA, 63 tRNA, 2 pseudogenes and a G + C content of 35.48 %.
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85
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Kumar B, Pathak R, Mary PB, Jha D, Sardana K, Gautam HK. New insights into acne pathogenesis: Exploring the role of acne-associated microbial populations. DERMATOL SIN 2016. [DOI: 10.1016/j.dsi.2015.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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86
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Buscetta M, Firon A, Pietrocola G, Biondo C, Mancuso G, Midiri A, Romeo L, Galbo R, Venza M, Venza I, Kaminski PA, Gominet M, Teti G, Speziale P, Trieu-Cuot P, Beninati C. PbsP, a cell wall-anchored protein that binds plasminogen to promote hematogenous dissemination of group B Streptococcus. Mol Microbiol 2016; 101:27-41. [PMID: 26888569 DOI: 10.1111/mmi.13357] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2016] [Indexed: 02/04/2023]
Abstract
Streptococcus agalactiae (Group B Streptococcus or GBS) is a leading cause of invasive infections in neonates whose virulence is dependent on its ability to interact with cells and host components. We here characterized a surface protein with a critical function in GBS pathophysiology. This adhesin, designated PbsP, possesses two Streptococcal Surface Repeat domains, a methionine and lysine-rich region, and a LPXTG cell wall-anchoring motif. PbsP mediates plasminogen (Plg) binding both in vitro and in vivo and we showed that cell surface-bound Plg can be activated into plasmin by tissue plasminogen activator to increase the bacterial extracellular proteolytic activity. Absence of PbsP results in a decreased bacterial transmigration across brain endothelial cells and impaired virulence in a murine model of infection. PbsP is conserved among the main GBS lineages and is a major plasminogen adhesin in non-CC17 GBS strains. Importantly, immunization of mice with recombinant PbsP confers protective immunity. Our results indicate that GBS have evolved different strategies to recruit Plg which indicates that the ability to acquire cell surface proteolytic activity is essential for the invasiveness of this bacterium.
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Affiliation(s)
- Marco Buscetta
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy.,Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Arnaud Firon
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Giampiero Pietrocola
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Carmelo Biondo
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Giuseppe Mancuso
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Angelina Midiri
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Letizia Romeo
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Roberta Galbo
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Mario Venza
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Isabella Venza
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Pierre-Alexandre Kaminski
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Myriam Gominet
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Giuseppe Teti
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, CNRS ERL3526, 75015, Paris, France
| | - Concetta Beninati
- Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy.,Scylla Biotech Srl, Messina, Italy
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87
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Mistou MY, Sutcliffe IC, van Sorge NM. Bacterial glycobiology: rhamnose-containing cell wall polysaccharides in Gram-positive bacteria. FEMS Microbiol Rev 2016; 40:464-79. [PMID: 26975195 PMCID: PMC4931226 DOI: 10.1093/femsre/fuw006] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2016] [Indexed: 12/21/2022] Open
Abstract
The composition of the Gram-positive cell wall is typically described as containing peptidoglycan, proteins and essential secondary cell wall structures called teichoic acids, which comprise approximately half of the cell wall mass. The cell walls of many species within the genera Streptococcus, Enterococcus and Lactococcus contain large amounts of the sugar rhamnose, which is incorporated in cell wall-anchored polysaccharides (CWP) that possibly function as homologues of well-studied wall teichoic acids (WTA). The presence and chemical structure of many rhamnose-containing cell wall polysaccharides (RhaCWP) has sometimes been known for decades. In contrast to WTA, insight into the biosynthesis and functional role of RhaCWP has been lacking. Recent studies in human streptococcal and enterococcal pathogens have highlighted critical roles for these complex polysaccharides in bacterial cell wall architecture and pathogenesis. In this review, we provide an overview of the RhaCWP with regards to their biosynthesis, genetics and biological function in species most relevant to human health. We also briefly discuss how increased knowledge in this field can provide interesting leads for new therapeutic compounds and improve biotechnological applications. This review summarizes new insights into the genetics and function of rhamnose-containing cell wall polysaccharides expressed by lactic acid bacteria, which includes medically important pathogens, and discusses perspectives on possible future therapeutic and biotechnological applications.
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Affiliation(s)
- Michel-Yves Mistou
- Laboratory for Food Safety, Université Paris-Est, ANSES, F-94701 Maisons-Alfort, France
| | - Iain C Sutcliffe
- Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Nina M van Sorge
- Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
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88
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Croucher NJ, Mostowy R, Wymant C, Turner P, Bentley SD, Fraser C. Horizontal DNA Transfer Mechanisms of Bacteria as Weapons of Intragenomic Conflict. PLoS Biol 2016; 14:e1002394. [PMID: 26934590 PMCID: PMC4774983 DOI: 10.1371/journal.pbio.1002394] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/29/2016] [Indexed: 01/21/2023] Open
Abstract
Horizontal DNA transfer (HDT) is a pervasive mechanism of diversification in many microbial species, but its primary evolutionary role remains controversial. Much recent research has emphasised the adaptive benefit of acquiring novel DNA, but here we argue instead that intragenomic conflict provides a coherent framework for understanding the evolutionary origins of HDT. To test this hypothesis, we developed a mathematical model of a clonally descended bacterial population undergoing HDT through transmission of mobile genetic elements (MGEs) and genetic transformation. Including the known bias of transformation toward the acquisition of shorter alleles into the model suggested it could be an effective means of counteracting the spread of MGEs. Both constitutive and transient competence for transformation were found to provide an effective defence against parasitic MGEs; transient competence could also be effective at permitting the selective spread of MGEs conferring a benefit on their host bacterium. The coordination of transient competence with cell-cell killing, observed in multiple species, was found to result in synergistic blocking of MGE transmission through releasing genomic DNA for homologous recombination while simultaneously reducing horizontal MGE spread by lowering the local cell density. To evaluate the feasibility of the functions suggested by the modelling analysis, we analysed genomic data from longitudinal sampling of individuals carrying Streptococcus pneumoniae. This revealed the frequent within-host coexistence of clonally descended cells that differed in their MGE infection status, a necessary condition for the proposed mechanism to operate. Additionally, we found multiple examples of MGEs inhibiting transformation through integrative disruption of genes encoding the competence machinery across many species, providing evidence of an ongoing "arms race." Reduced rates of transformation have also been observed in cells infected by MGEs that reduce the concentration of extracellular DNA through secretion of DNases. Simulations predicted that either mechanism of limiting transformation would benefit individual MGEs, but also that this tactic's effectiveness was limited by competition with other MGEs coinfecting the same cell. A further observed behaviour we hypothesised to reduce elimination by transformation was MGE activation when cells become competent. Our model predicted that this response was effective at counteracting transformation independently of competing MGEs. Therefore, this framework is able to explain both common properties of MGEs, and the seemingly paradoxical bacterial behaviours of transformation and cell-cell killing within clonally related populations, as the consequences of intragenomic conflict between self-replicating chromosomes and parasitic MGEs. The antagonistic nature of the different mechanisms of HDT over short timescales means their contribution to bacterial evolution is likely to be substantially greater than previously appreciated.
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Affiliation(s)
- Nicholas J. Croucher
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Rafal Mostowy
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Christopher Wymant
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Paul Turner
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Stephen D. Bentley
- Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Christophe Fraser
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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89
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Shabayek S, Bauer R, Mauerer S, Mizaikoff B, Spellerberg B. A streptococcal NRAMP homologue is crucial for the survival of Streptococcus agalactiae under low pH conditions. Mol Microbiol 2016; 100:589-606. [PMID: 27150893 DOI: 10.1111/mmi.13335] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2016] [Indexed: 12/25/2022]
Abstract
Streptococcus agalactiae or Group B Streptococcus (GBS) is a commensal bacterium of the human gastrointestinal and urogenital tracts as well as a leading cause of neonatal sepsis, pneumonia and meningitis. Maternal vaginal carriage is the main source for GBS transmission and thus the most important risk factor for neonatal disease. Several studies in eukaryotes identified a group of proteins natural resistance-associated macrophage protein (NRAMP) that function as divalent cation transporters for Fe(2+) and Mn(2+) and confer on macrophages the ability to control replication of bacterial pathogens. Genome sequencing predicted potential NRAMP homologues in several prokaryotes. Here we describe for the first time, a pH-regulated NRAMP Mn(2+) /Fe(2+) transporter in GBS, designated MntH, which confers resistance to reactive oxygen species (ROS) and is crucial for bacterial growth and survival under low pH conditions. Our investigation implicates MntH as an important colonization determinant for GBS in the maternal vagina as it helps bacteria to adapt to the harsh acidic environment, facilitates bacterial adherence, contributes to the coexistence with the vaginal microbiota and plays a role in GBS intracellular survival inside macrophages.
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Affiliation(s)
- Sarah Shabayek
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany.,Microbiology and Immunology Department, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
| | - Richard Bauer
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
| | - Stefanie Mauerer
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
| | - Boris Mizaikoff
- Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Ulm, Germany
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
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90
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Sadeh M, Firouzi R, Derakhshandeh A, Bagher Khalili M, Kong F, Kudinha T. Molecular Characterization of Streptococcus agalactiae Isolates From Pregnant and Non-Pregnant Women at Yazd University Hospital, Iran. Jundishapur J Microbiol 2016; 9:e30412. [PMID: 27127592 PMCID: PMC4842249 DOI: 10.5812/jjm.30412] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 11/28/2015] [Accepted: 11/28/2015] [Indexed: 11/30/2022] Open
Abstract
Background: Streptococcus agalactiae (Group B streptococcus, GBS) that colonize the vaginas of pregnant women may occasionally cause neonatal infections. It is one of the most common causes of sepsis and meningitis in neonates and of invasive diseases in pregnant women. It can also cause infectious disease among immunocompromised individuals. The distribution of capsular serotypes and genotypes varies over time and by geographic era. The serotyping and genotyping data of GBS in Iranian pregnant and non-pregnant women seems very limited. Objectives: The aim of this study was to investigate the GBS molecular capsular serotype and genotype distribution of pregnant and non-pregnant carrier women at Yazd university hospital, in Iran. Patients and Methods: In this cross-sectional study, a total of 100 GBS strains isolated from 237 pregnant and 413 non-pregnant women were investigated for molecular capsular serotypes and surface protein genes using the multiplex PCR assay. The Chi-square method was used for statistical analysis. Results: Out of 650 samples, 100 (15.4%) were identified as GBS, with a predominance of capsular serotypes III (50%) [III-1 (49), III-3 (1)], followed by II (25%), Ia (12%), V (11%), and Ib (2%), which was similar with another study conducted in Tehran, Iran, but they had no serotype Ia in their report. The surface protein antigen genes distribution was rib (53%), epsilon (38%), alp2/3 (6%), and alpha-c (3%). Conclusions: The determination of serotype and surface proteins of GBS strains distribution would be relevant for the future possible formulation of a GBS vaccine.
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Affiliation(s)
- Maryam Sadeh
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, IR Iran
| | - Roya Firouzi
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, IR Iran
| | - Abdollah Derakhshandeh
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, IR Iran
- Corresponding author: Abdollah Derakhshandeh, Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, IR Iran. Tel: +98-7136138666, Fax: +98-7132286940, E-mail:
| | | | - Fanrong Kong
- Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR-Pathology West, Westmead Hospital, University of Sydney, New South Wales 2145, Australia
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91
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Delannoy CMJ, Zadoks RN, Crumlish M, Rodgers D, Lainson FA, Ferguson HW, Turnbull J, Fontaine MC. Genomic comparison of virulent and non-virulent Streptococcus agalactiae in fish. JOURNAL OF FISH DISEASES 2016; 39:13-29. [PMID: 25399660 DOI: 10.1111/jfd.12319] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 09/05/2014] [Accepted: 09/06/2014] [Indexed: 06/04/2023]
Abstract
Streptococcus agalactiae infections in fish are predominantly caused by beta-haemolytic strains of clonal complex (CC) 7, notably its namesake sequence type (ST) 7, or by non-haemolytic strains of CC552, including the globally distributed ST260. In contrast, CC23, including its namesake ST23, has been associated with a wide homeothermic and poikilothermic host range, but never with fish. The aim of this study was to determine whether ST23 is virulent in fish and to identify genomic markers of fish adaptation of S. agalactiae. Intraperitoneal challenge of Nile tilapia, Oreochromis niloticus (Linnaeus), showed that ST260 is lethal at doses down to 10(2) cfu per fish, whereas ST23 does not cause disease at 10(7) cfu per fish. Comparison of the genome sequence of ST260 and ST23 with those of strains derived from fish, cattle and humans revealed the presence of genomic elements that are unique to subpopulations of S. agalactiae that have the ability to infect fish (CC7 and CC552). These loci occurred in clusters exhibiting typical signatures of mobile genetic elements. PCR-based screening of a collection of isolates from multiple host species confirmed the association of selected genes with fish-derived strains. Several fish-associated genes encode proteins that potentially provide fitness in the aquatic environment.
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Affiliation(s)
- C M J Delannoy
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, UK
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - R N Zadoks
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - M Crumlish
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, UK
| | - D Rodgers
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - F A Lainson
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - H W Ferguson
- School of Veterinary Medicine, St. George's University, St. George's, Grenada, West Indies
| | - J Turnbull
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, UK
| | - M C Fontaine
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
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92
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Ponnuvel S, Bandaru D, Ragunathan P, Ponnuraj K. Functional characterization and molecular modelling of FnFgBP, a surface protein from Streptococcus agalactiae. RSC Adv 2016. [DOI: 10.1039/c6ra18275e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
GBS1263 (FnFgBP) exhibits dual-ligand (fibronectin and fibrinogen) binding property. Molecular modeling of FnFgBP is suggestive of a unique ligand binding mechanism.
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Affiliation(s)
- Shobana Ponnuvel
- Centre of Advanced Study in Crystallography and Biophysics
- University of Madras
- Chennai-600 025
- India
| | - Dhanalakshmi Bandaru
- Centre of Advanced Study in Crystallography and Biophysics
- University of Madras
- Chennai-600 025
- India
| | - Preethi Ragunathan
- Centre of Advanced Study in Crystallography and Biophysics
- University of Madras
- Chennai-600 025
- India
| | - Karthe Ponnuraj
- Centre of Advanced Study in Crystallography and Biophysics
- University of Madras
- Chennai-600 025
- India
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93
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SepM, a Streptococcal Protease Involved in Quorum Sensing, Displays Strict Substrate Specificity. J Bacteriol 2015; 198:436-47. [PMID: 26553848 DOI: 10.1128/jb.00708-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/01/2015] [Indexed: 02/02/2023] Open
Abstract
UNLABELLED Streptococcus mutans, a causative agent of dental caries, relies on multiple quorum-sensing (QS) pathways that coordinate the expression of factors needed for colonization in the oral cavity. S. mutans uses small peptides as QS signaling molecules that typically are secreted into the outside milieu. Competence-stimulating peptide (CSP) is one such QS signaling molecule that functions through the ComDE two-component signal transduction pathway. CSP is secreted through NlmTE, a dedicated ABC transporter that cleaves off the N-terminal leader peptide to generate a mature peptide that is 21 residues long (CSP-21). We recently identified a surface-localized protease, SepM, which further cleaves the CSP-21 peptide at the C-terminal end and removes the last 3 residues to generate CSP-18. CSP-18 is the active QS molecule that interacts with the ComD sensor kinase to activate the QS pathway. In this study, we show that SepM specifically cleaves CSP-21 between the Ala18 and Leu19 residues. We also show that SepM recognizes only Ala at position 18 and Leu at position 19, although some CSP-18 variants with a substitution at position 18 can function equally as well as the QS peptide. Furthermore, we demonstrate that SepM homologs from other streptococci are capable of processing CSP-21 to generate functional CSP-18. IMPORTANCE SepM is a membrane-associated streptococcal protease that processes competence-stimulating peptide (CSP) to generate an active quorum-sensing molecule in S. mutans. SepM belongs to the S16 family of serine proteases, and in this study, we found that SepM behaves as an endopeptidase. SepM displays strict substrate specificity and cleaves the peptide bond between the Ala and Leu residues. This is the first report of an endopeptidase that specifically cleaves these two residues.
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94
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Seo JS, Kwon MG, Hwang JY, Jung SH, Han HJ, Kim MS, Do JW, Park MA, Kim DW, Cho WS, Lee K. Complete genome sequence and comparative genome analysis of Streptococcus parauberis KCTC11980. Genes Genomics 2015. [DOI: 10.1007/s13258-015-0325-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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95
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Molecular Characterization of Nonhemolytic and Nonpigmented Group B Streptococci Responsible for Human Invasive Infections. J Clin Microbiol 2015; 54:75-82. [PMID: 26491182 DOI: 10.1128/jcm.02177-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 10/12/2015] [Indexed: 12/22/2022] Open
Abstract
Group B Streptococcus (GBS) is a common commensal bacterium in adults, but is also the leading cause of invasive bacterial infections in neonates in developed countries. The β-hemolysin/cytolysin (β-h/c), which is always associated with the production of an orange-to-red pigment, is a major virulence factor that is also used for GBS diagnosis. A collection of 1,776 independent clinical GBS strains isolated in France between 2006 and 2013 was evaluated on specific medium for β-h/c activity and pigment production. The genomic sequences of nonhemolytic and nonpigmented (NH/NP) strains were analyzed to identify the molecular basis of this phenotype. Gene deletions or complementations were carried out to confirm the genotype-phenotype association. Sixty-three GBS strains (3.5%) were NH/NP, and 47 of these (74.6%) originated from invasive infections, including bacteremia and meningitis, in neonates or adults. The mutations are localized predominantly in the cyl operon, encoding the β-h/c pigment biosynthetic pathway and, in the abx1 gene, encoding a CovSR regulator partner. In conclusion, although usually associated with GBS virulence, β-h/c pigment production is not absolutely required to cause human invasive infections. Caution should therefore be taken in the use of hemolysis and pigmentation as criteria for GBS diagnosis in routine clinical laboratory settings.
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96
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Morello E, Mallet A, Konto-Ghiorghi Y, Chaze T, Mistou MY, Oliva G, Oliveira L, Di Guilmi AM, Trieu-Cuot P, Dramsi S. Evidence for the Sialylation of PilA, the PI-2a Pilus-Associated Adhesin of Streptococcus agalactiae Strain NEM316. PLoS One 2015; 10:e0138103. [PMID: 26407005 PMCID: PMC4583379 DOI: 10.1371/journal.pone.0138103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/25/2015] [Indexed: 01/20/2023] Open
Abstract
Streptococcus agalactiae (or Group B Streptococcus, GBS) is a commensal bacterium present in the intestinal and urinary tracts of approximately 30% of humans. We and others previously showed that the PI-2a pilus polymers, made of the backbone pilin PilB, the tip adhesin PilA and the cell wall anchor protein PilC, promote adhesion to host epithelia and biofilm formation. Affinity-purified PI-2a pili from GBS strain NEM316 were recognized by N-acetylneuraminic acid (NeuNAc, also known as sialic acid) specific lectins such as Elderberry Bark Lectin (EBL) suggesting that pili are sialylated. Glycan profiling with twenty different lectins combined with monosaccharide composition by HPLC suggested that affinity-purified PI-2a pili are modified by N-glycosylation and decorated with sialic acid attached to terminal galactose. Analysis of various relevant mutants in the PI-2a pilus operon by flow-cytometry and electron microscopy analyses pointed to PilA as the pilus subunit modified by glycosylation. Double labeling using PilB antibody and EBL lectin, which specifically recognizes N-acetylneuraminic acid attached to galactose in α-2, 6, revealed a characteristic binding of EBL at the tip of the pilus structures, highly reminiscent of PilA localization. Expression of a secreted form of PilA using an inducible promoter showed that this recombinant PilA binds specifically to EBL lectin when produced in the native GBS context. In silico search for potentially glycosylated asparagine residues in PilA sequence pointed to N427 and N597, which appear conserved and exposed in the close homolog RrgA from S. pneumoniae, as likely candidates. Conversion of these two asparagyl residues to glutamyl resulted in a higher instability of PilA. Our results provide the first evidence that the tip PilA adhesin can be glycosylated, and suggest that this modification is critical for PilA stability and may potentially influence interactions with the host.
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Affiliation(s)
- Eric Morello
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Adeline Mallet
- Institut Pasteur, Imagopole, Ultrastructural Microscopy Platform, Paris, France
| | - Yoan Konto-Ghiorghi
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Thibault Chaze
- Institut Pasteur, Spectrométrie de Masse Structurale et Protéomique, Paris, France
- INRA UMR 1319, MICALIS, Jouy-en-Josas, France
| | | | - Giulia Oliva
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Liliana Oliveira
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Anne-Marie Di Guilmi
- Université Grenoble Alpes, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Shaynoor Dramsi
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
- * E-mail:
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97
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Nuccitelli A, Rinaudo CD, Maione D. Group B Streptococcus vaccine: state of the art. THERAPEUTIC ADVANCES IN VACCINES 2015; 3:76-90. [PMID: 26288735 DOI: 10.1177/2051013615579869] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Group B Streptococcus (GBS) is cause of neonatal invasive diseases as well as of severe infections in the elderly and immune-compromised patients. Despite significant advances in the prevention and treatment of neonatal disease, sepsis and meningitis caused by GBS still represent a significant public health care concern globally and additional prevention and therapeutic strategies against infection are highly desirable. The introduction of national recommended guidelines in several countries to screen pregnant women for GBS carriage and the use of antibiotics during delivery significantly reduced disease occurring within the first hours of life (early-onset disease), but it has had no effect on the late-onset diseases occurring after the first week and is not feasible in most countries. Availability of an effective vaccine against GBS would provide an effective means of controlling GBS disease. This review provides an overview of the burden of invasive disease caused by GBS in infants and adults, and highlights the strategies for the development of an effective vaccine against GBS infections.
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Affiliation(s)
| | | | - Domenico Maione
- Novartis Vaccines and Diagnostics, via Fiorentina 1, 53100 Siena, Italy
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98
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Whole-Genome Comparison Uncovers Genomic Mutations between Group B Streptococci Sampled from Infected Newborns and Their Mothers. J Bacteriol 2015; 197:3354-66. [PMID: 26283765 DOI: 10.1128/jb.00429-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/05/2015] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Streptococcus agalactiae (group B Streptococcus or GBS), a commensal of the human gut and genitourinary tract, is a leading cause of neonatal infections, in which vertical transmission from mother to child remains the most frequent route of contamination. Here, we investigated whether the progression of GBS from carriage to disease is associated with genomic adaptation. Whole-genome comparison of 47 GBS samples from 19 mother-child pairs uncovered 21 single nucleotide polymorphisms (SNPs) and seven insertions/deletions. Of the SNPs detected, 16 appear to have been fixed in the population sampled whereas five mutations were found to be polymorphic. In the infant strains, 14 mutations were detected, including two independently fixed variants affecting the covRS locus, which is known to encode a major regulatory system of virulence. A one-nucleotide insertion was also identified in the promoter region of the highly immunogenic surface protein Rib gene. Gene expression analysis after incubation in human blood showed that these mutations influenced the expression of virulence-associated genes. Additional identification of three mutated strains in the mothers' milk raised the possibility of the newborns also being a source of contamination for their mothers. Overall, our work showed that GBS strains in carriage and disease scenarios might undergo adaptive changes following colonization. The types and locations of the mutations found, together with the experimental results showing their phenotypic impact, suggest that those in a context of infection were positively selected during the transition of GBS from commensal to pathogen, contributing to an increased capacity to cause disease. IMPORTANCE Group B Streptococcus (GBS) is a major pathogen responsible for neonatal infections. Considering that its colonization of healthy adults is mostly asymptomatic, the mechanisms behind its switch from a commensal to an invasive state are largely unknown. In this work, we compared the genomic profile of GBS samples causing infections in newborns with that of the GBS colonizing their mothers. Multiple mutations were detected, namely, within key virulence factors, including the response regulator CovR and surface protein Rib, potentially affecting the pathogenesis of GBS. Their overall impact was supported by differences in the expression of virulence-associated genes in human blood. Our results suggest that during GBS's progression to disease, particular variants are positively selected, contributing to the ability of this bacterium to infect its host.
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99
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Bessen DE, McShan WM, Nguyen SV, Shetty A, Agrawal S, Tettelin H. Molecular epidemiology and genomics of group A Streptococcus. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2015; 33:393-418. [PMID: 25460818 PMCID: PMC4416080 DOI: 10.1016/j.meegid.2014.10.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 10/11/2014] [Accepted: 10/13/2014] [Indexed: 12/15/2022]
Abstract
Streptococcus pyogenes (group A Streptococcus; GAS) is a strict human pathogen with a very high prevalence worldwide. This review highlights the genetic organization of the species and the important ecological considerations that impact its evolution. Recent advances are presented on the topics of molecular epidemiology, population biology, molecular basis for genetic change, genome structure and genetic flux, phylogenomics and closely related streptococcal species, and the long- and short-term evolution of GAS. The application of whole genome sequence data to addressing key biological questions is discussed.
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Affiliation(s)
- Debra E Bessen
- Department of Microbiology & Immunology, New York Medical College, Valhalla, NY 10595, USA.
| | - W Michael McShan
- University of Oklahoma Health Sciences Center, Department of Pharmaceutical Sciences, College of Pharmacy, Oklahoma City, OK 73117, USA.
| | - Scott V Nguyen
- University of Oklahoma Health Sciences Center, Department of Pharmaceutical Sciences, College of Pharmacy, Oklahoma City, OK 73117, USA.
| | - Amol Shetty
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Sonia Agrawal
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Hervé Tettelin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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100
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Lier C, Baticle E, Horvath P, Haguenoer E, Valentin AS, Glaser P, Mereghetti L, Lanotte P. Analysis of the type II-A CRISPR-Cas system of Streptococcus agalactiae reveals distinctive features according to genetic lineages. Front Genet 2015; 6:214. [PMID: 26124774 PMCID: PMC4466440 DOI: 10.3389/fgene.2015.00214] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 06/01/2015] [Indexed: 12/12/2022] Open
Abstract
CRISPR-Cas systems (clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins) are found in 90% of archaea and about 40% of bacteria. In this original system, CRISPR arrays comprise short, almost unique sequences called spacers that are interspersed with conserved palindromic repeats. These systems play a role in adaptive immunity and participate to fight non-self DNA such as integrative and conjugative elements, plasmids, and phages. In Streptococcus agalactiae, a bacterium implicated in colonization and infections in humans since the 1960s, two CRISPR-Cas systems have been described. A type II-A system, characterized by proteins Cas9, Cas1, Cas2, and Csn2, is ubiquitous, and a type I–C system, with the Cas8c signature protein, is present in about 20% of the isolates. Unlike type I–C, which appears to be non-functional, type II-A appears fully functional. Here we studied type II-A CRISPR-cas loci from 126 human isolates of S. agalactiae belonging to different clonal complexes that represent the diversity of the species and that have been implicated in colonization or infection. The CRISPR-cas locus was analyzed both at spacer and repeat levels. Major distinctive features were identified according to the phylogenetic lineages previously defined by multilocus sequence typing, especially for the sequence type (ST) 17, which is considered hypervirulent. Among other idiosyncrasies, ST-17 shows a significantly lower number of spacers in comparison with other lineages. This characteristic could reflect the peculiar virulence or colonization specificities of this lineage.
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Affiliation(s)
- Clément Lier
- UMR1282 Infectiologie et Santé Publique, Bactéries et Risque Materno-Foetal, Université de Tours, Tours France ; INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly France ; Service de Bactériologie-Virologie, Hôpital Bretonneau - Centre Hospitalier Régional et Universitaire de Tours, Tours France
| | - Elodie Baticle
- Service de Bactériologie-Virologie, Hôpital Bretonneau - Centre Hospitalier Régional et Universitaire de Tours, Tours France
| | | | - Eve Haguenoer
- UMR1282 Infectiologie et Santé Publique, Bactéries et Risque Materno-Foetal, Université de Tours, Tours France ; INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly France
| | - Anne-Sophie Valentin
- UMR1282 Infectiologie et Santé Publique, Bactéries et Risque Materno-Foetal, Université de Tours, Tours France ; INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly France ; Service de Bactériologie-Virologie, Hôpital Bretonneau - Centre Hospitalier Régional et Universitaire de Tours, Tours France
| | - Philippe Glaser
- Unité de Biologie des Bactéries Pathogènes à Gram Positif, Institut Pasteur, Paris France ; CNRS UMR 3525, Paris France
| | - Laurent Mereghetti
- UMR1282 Infectiologie et Santé Publique, Bactéries et Risque Materno-Foetal, Université de Tours, Tours France ; INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly France ; Service de Bactériologie-Virologie, Hôpital Bretonneau - Centre Hospitalier Régional et Universitaire de Tours, Tours France
| | - Philippe Lanotte
- UMR1282 Infectiologie et Santé Publique, Bactéries et Risque Materno-Foetal, Université de Tours, Tours France ; INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly France ; Service de Bactériologie-Virologie, Hôpital Bretonneau - Centre Hospitalier Régional et Universitaire de Tours, Tours France
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