title: Molecular Characteristics of Group B Streptococci Isolated from Adults with Invasive Infections in Japan.
abstract: Streptococcus agalactiae (group B streptococcus) isolates (n = 443) obtained from Japanese adults with invasive infections between April 2010 and March 2013 were analyzed for capsular serotype, multilocus sequence type (ST), antibiotic susceptibility, and resistance genes. Among these cases, bacteremia without primary focus was the most common variety of infection (49.9%), followed by cellulitis (12.9%) and pneumonia (9.0%). Concerning patient age (18 to 59, 60 to 69, 70 to 79, 80 to 89, and 90 years old or older), the incidence of pneumonia increased in patients in their 70s and 80s (P < 0.001), while younger patients (18 to 59 and 60 to 69 years old) were more likely to have abscesses (P < 0.05). The mortality rate was 10.2% for all ages. The most common capsular serotype was Ib (39.5%), followed by V (16.0%), III (13.8%), VI (9.5%), and Ia (8.6%). The main ST of serotype Ib strains was ST10, which belonged to clonal complex 10 (88.0%). The predominant clonal complexes of serotypes V and III, respectively, were 1 (78.9%) and 19 (75.4%). Among these isolates, 9 strains (2.0%) were identified as group B streptococci with reduced penicillin susceptibility, reflecting amino acid substitutions in penicillin-binding protein 2X (PBP2X). In addition, 19.2% of all strains possessed mef(A/E), erm(A), or erm(B) genes, which mediate macrolide resistance, while 40.2% of strains were resistant to quinolones resulting from amino acid substitutions in GyrA and ParC. Our data argue strongly for the continuous surveillance of microbial characteristics and judicious antibiotic use in clinical practice.
authors: Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
authors: Miyuki
authors: M
authors: Morozumi
authors: Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors: Takeaki
authors: T
authors: Wajima
authors: Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
authors: Misako
authors: M
authors: Takata
authors: Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
authors: Satoshi
authors: S
authors: Iwata
authors: Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan ubukatak@keio.jp.
authors: Kimiko
authors: K
authors: Ubukata
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology; D002481:Cellulitis / Q000453:epidemiology / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D005260:Female; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009026:Mortality; D058885:Multilocus Sequence Typing; D018410:Pneumonia, Bacterial / Q000453:epidemiology / Q000382:microbiology; D012703:Serotyping; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D055815:Young Adult