title: Clonal analysis of colonizing group B Streptococcus, serotype IV, an emerging pathogen in the United States.
abstract: Colonizing group B Streptococcus (GBS) capsular polysaccharide (CPS) type IV isolates were recovered from vaginal and rectal samples obtained from 97 (8.4%) nonpregnant women of 1,160 women enrolled in a U.S. multicenter GBS vaccine study from 2004 to 2008. Since this rate was much higher than the rate of prevalence of 0.4 to 0.6% that we found in previous studies, the isolates were analyzed by using surface protein profile identification, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) to characterize them and identify trends in DNA clonality and divergence. Of the 101 type IV isolates studied, 53 expressed alpha and group B protective surface (BPS) proteins, 27 expressed BPS only, 20 expressed alpha only, and 1 had no detectable surface proteins. The isolates spanned three PFGE macrorestriction profile groups, groups 37, 38, and 39, of which group 37 was predominant. The isolates in group 37 expressed the alpha and BPS proteins, while those in groups 38 and 39 expressed the alpha protein only, with two exceptions. MLST studies of selective isolates from the four protein profile groups showed that isolates expressing alpha,BPS or BPS only were of a new sequence type, sequence type 452, while those expressing alpha only or no proteins were mainly of a new sequence type, sequence type 459. Overall, our study revealed a limited diversity in surface proteins, MLST types, and DNA macrorestriction profiles for type IV GBS. There appeared to be an association between the MLST types and protein expression profiles. The increased prevalence of type IV GBS colonization suggested the possibility that this serotype may emerge as a GBS pathogen.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, 420 Delaware St. SE, Mayo Mail Code 134, Minneapolis, MN 55455, USA.
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Diedrick
authors.forename: Aurea E
authors.initials: AE
authors.lastname: Flores
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Hillier
authors.forename: Roberta
authors.initials: R
authors.lastname: Creti
authors.forename: Patricia
authors.initials: P
authors.lastname: Ferrieri
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006801:Humans; D017720:Molecular Epidemiology / Q000379:methods; D012007:Rectum / Q000382:microbiology; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D014481:United States; D014621:Vagina / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins