Dataset Information

Emergence and global dissemination of host-specific Streptococcus agalactiae clones.

ABSTRACT: To examine the global diversity of Streptococcus agalactiae (group B streptococci [GBS]) and to elucidate the evolutionary processes that determine its population genetics structure and the reported changes in host tropism and infection epidemiology, we examined a collection of 238 bovine and human isolates from nine countries on five continents. Phylogenetic analysis based on the sequences of 15 housekeeping genes combined with patterns of virulence-associated traits identified a genetically heterogeneous core population from which virulent lineages occasionally emerge as a result of recombination affecting major segments of the genome. Such lineages, like clonal complex 17 (CC17) and two distinct clusters of CC23, are exclusively adapted to either humans or cattle and successfully spread globally. The recent emergence and expansion of the human-associated and highly virulent sequence type 17 (ST17) could conceivably account, in part, for the increased prevalence of neonatal GBS infections after 1960. The composite structure of the S. agalactiae genome invalidates phylogenetic inferences exclusively based on multilocus sequence typing (MLST) data and thereby the previously reported conclusion that the human-associated CC17 emerged from the bovine-associated CC67.

SUBMITTER: Sorensen UB

PROVIDER: S-EPMC2932510 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Emergence and global dissemination of host-specific Streptococcus agalactiae clones.

Sørensen Uffe B Skov UB Poulsen Knud K Ghezzo Claudia C Margarit Immaculada I Kilian Mogens M

mBio 20100824 3

To examine the global diversity of Streptococcus agalactiae (group B streptococci [GBS]) and to elucidate the evolutionary processes that determine its population genetics structure and the reported changes in host tropism and infection epidemiology, we examined a collection of 238 bovine and human isolates from nine countries on five continents. Phylogenetic analysis based on the sequences of 15 housekeeping genes combined with patterns of virulence-associated traits identified a genetically he ...[more]

PMID: 20824105

Similar Datasets

Project description:IntroductionStreptococcus agalactiae (Group B Streptococcus, GBS), a Gram-positive commensal in healthy adults, remains a major cause of neonatal infections, usually manifesting as sepsis, meningitis, or pneumonia. Intrapartum antibiotic prophylaxis has greatly reduced the incidence of early-onset disease. However, given the lack of effective measures to prevent the risk of late-onset disease and invasive infections in immunocompromised individuals, more studies investigating the GBS-associated pathogenesis and the interplay between bacteria and host immune system are needed.MethodsHere, we examined the impact of 12 previously genotyped GBS isolates belonging to different serotypes and sequence types on the immune response of THP-1 macrophages.ResultsFlow cytometry analysis showed isolate-specific differences in phagocytic uptake, ranging from 10% for isolates of serotype Ib, which possess the virulence factor protein β, to over 70% for isolates of serotype III. Different isolates also induced differential expression of co-stimulatory molecules and scavenger receptors with colonizing isolates inducing higher expression levels of CD80 and CD86 compared to invasive isolates. In addition, real-time measurements of metabolism revealed that macrophages enhanced both glycolysis and mitochondrial respiration after GBS infection, with isolates of serotype III being the most potent activators of glycolysis and glycolytic ATP production. Macrophages also showed differential resistance to GBS-mediated cell cytotoxicity as measured by LDH release and real-time microscopy. The differences were evident both between serotypes and between isolates obtained from different specimens (colonizing or invasive isolates) demonstrating the higher cytotoxicity of vaginal compared with blood isolates.ConclusionsThus, the data suggest that GBS isolates differ in their potential to become invasive or remain colonizing. In addition, colonizing isolates appear to be more cytotoxic, whereas invasive isolates appear to exploit macrophages to their advantage, avoiding the immune recognition and antibiotics.

Dataset Information

Emergence and global dissemination of host-specific Streptococcus agalactiae clones.

Publications

Emergence and global dissemination of host-specific Streptococcus agalactiae clones.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets