title: Associations between capsular serotype, multilocus sequence type, and macrolide resistance in Streptococcus agalactiae isolates from Japanese infants with invasive infections.
abstract: SUMMARY Streptococcus agalactiae (group B streptococcus; GBS) isolates (n = 150) from infants with invasive infections between 2006 and 2011 were analysed for capsular serotype, multilocus sequence type, and antibiotic susceptibility. In cases with late-onset disease (n = 115), primary meningitis was predominant (62.6%), but represented only 39.1% in cases with early-onset disease (n = 23). The most common serotype was III (58.7%), followed by Ia (21.3%) and Ib (12.7%). Sequence types (STs) of serotype III strains included ST17 (50.0%), ST19 (26.1%), ST335 (18.2%), ST27 (4.5%), and ST1 (1.1%). Predominant STs of serotypes Ia and Ib were ST23 (81.3%) and ST10 (84.2%), respectively. No penicillin-resistant strains were detected, but 22·0% of strains had mef(A/E), erm(A), or erm(B) genes, which mediate macrolide resistance. A new ST335, possessing an mef(A/E) gene belonging to clonal complex 19 gradually increased in frequency. Improved prevention of invasive GBS infections in infants requires timely identification, and ultimately vaccine development.
authors.affiliation: Laboratory of Molecular Epidemiology for Infectious Agents, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Morozumi
authors.affiliation: Laboratory of Molecular Epidemiology for Infectious Agents, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Wajima
authors.affiliation: Laboratory of Molecular Epidemiology for Infectious Agents, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kuwata
authors.affiliation: Laboratory of Molecular Epidemiology for Infectious Agents, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Chiba
authors.affiliation: Department of Clinical Microbiology, Saitama Institute of Public Health, Saitama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sunaoshi
authors.affiliation: Center for Infectious Diseases and Infection Control, Keio University School of Medicine, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sugita
authors.affiliation: Department of Pediatrics, Asahikawa-Kosei General Hospital, Hokkaido, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sakata
authors.affiliation: Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Iwata
authors.affiliation: Laboratory of Molecular Epidemiology for Infectious Agents, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ubukata
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016667:Bacterial Capsules / Q000235:genetics*; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases; D007564:Japan; D018942:Macrolides / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides