title: Clonal Complex 17 Group B Streptococcus strains causing invasive disease in neonates and adults originate from the same genetic pool.
abstract: A significant proportion of group B Streptococcus (GBS) neonatal disease, particularly late-onset disease, is associated with strains of serotype III, clonal complex (CC) 17. CC17 strains also cause invasive infections in adults. Little is known about the phylogenetic relationships of isolates recovered from neonatal and adult CC17 invasive infections. We performed whole-genome-based phylogenetic analysis of 93 temporally and geographically matched CC17 strains isolated from both neonatal and adult invasive infections in the metropolitan region of Toronto/Peel, Canada. We also mined the whole-genome data to reveal mobile genetic elements carrying antimicrobial resistance genes. We discovered that CC17 GBS strains causing neonatal and adult invasive disease are interspersed and cluster tightly in a phylogenetic tree, signifying that they are derived from the same genetic pool. We identified limited variation due to recombination in the core CC17 genome. We describe that loss of Pilus Island 1 and acquisition of different mobile genetic elements carrying determinants of antimicrobial resistance contribute to CC17 genetic diversity. Acquisition of some of these mobile genetic elements appears to correlate with clonal expansion of the strains that possess them. Our results provide a genome-wide portrait of the population structure and evolution of a major disease-causing clone of an opportunistic pathogen.
authors: Public Health Ontario, Toronto, ON, Canada.
authors: Sarah
authors: S
authors: Teatero
authors: Public Health Ontario, Toronto, ON, Canada.
authors: Erin
authors: E
authors: Ramoutar
authors: Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.|Mount Sinai Hospital, Toronto, ON, Canada.
authors: Allison
authors: A
authors: McGeer
authors: Public Health Ontario, Toronto, ON, Canada.
authors: Aimin
authors: A
authors: Li
authors: Public Health Ontario, Toronto, ON, Canada.|Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.|Mount Sinai Hospital, Toronto, ON, Canada.
authors: Roberto G
authors: RG
authors: Melano
authors: Department of Human Genetics, McGill University and Génome Québec Innovation Centre, Montreal, QC, Canada.
authors: Jessica
authors: J
authors: Wasserscheid
authors: Department of Human Genetics, McGill University and Génome Québec Innovation Centre, Montreal, QC, Canada.
authors: Ken
authors: K
authors: Dewar
authors: Public Health Ontario, Toronto, ON, Canada.|Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
authors: Nahuel
authors: N
authors: Fittipaldi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002170:Canada; D002648:Child; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D016680:Genome, Bacterial; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA; D065288:Serogroup; D013290:Streptococcal Infections / Q000382:microbiology* / Q000473:pathology; D013292:Streptococcus agalactiae / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D013752:Tetracycline