title: Population structure and antimicrobial resistance of invasive serotype IV group B Streptococcus, Toronto, Ontario, Canada.
abstract: We recently showed that 37/600 (6.2%) invasive infections with group B Streptococcus (GBS) in Toronto, Ontario, Canada, were caused by serotype IV strains. We report a relatively high level of genetic diversity in 37 invasive strains of this emerging GBS serotype. Multilocus sequence typing identified 6 sequence types (STs) that belonged to 3 clonal complexes. Most isolates were ST-459 (19/37, 51%) and ST-452 (11/37, 30%), but we also identified ST-291, ST-3, ST-196, and a novel ST-682. We detected further diversity by performing whole-genome single-nucleotide polymorphism analysis and found evidence of recombination events contributing to variation in some serotype IV GBS strains. We also evaluated antimicrobial drug resistance and found that ST-459 strains were resistant to clindamycin and erythromycin, whereas strains of other STs were, for the most part, susceptible to these antimicrobial drugs.
authors: Sarah
authors: S
authors: Teatero
authors: Allison
authors: A
authors: McGeer
authors: Aimin
authors: A
authors: Li
authors: Janice
authors: J
authors: Gomes
authors: Christine
authors: C
authors: Seah
authors: Walter
authors: W
authors: Demczuk
authors: Irene
authors: I
authors: Martin
authors: Jessica
authors: J
authors: Wasserscheid
authors: Ken
authors: K
authors: Dewar
authors: Roberto G
authors: RG
authors: Melano
authors: Nahuel
authors: N
authors: Fittipaldi
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D019295:Computational Biology; D024881:Drug Resistance, Bacterial; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D009864:Ontario / Q000453:epidemiology; D010802:Phylogeny; D011159:Population Surveillance; D065288:Serogroup; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D000890:Anti-Infective Agents
keywords: Canada; Streptococcus agalactiae; Toronto; antimicrobial resistance; bacteria; bacterial infection; group B Streptococcus; invasive bacterial disease; multilocus sequence typing; population structure; serotype IV; streptococci; whole-genome sequencing