title: Phylogenetic classification of serotype III group B streptococci on the basis of hylB gene analysis and DNA sequences specific to restriction digest pattern type III-3.
abstract: Previous work divided serotype III group B streptococci (GBS) into 3 major phylogenetic lineages (III-1, III-2, and III-3) on the basis of bacterial DNA restriction digest patterns (RDPs). Most neonatal invasive disease was caused by III-3 strains, which implies that III-3 strains are more virulent than III-2 or III-1 strains. In the current studies, all RDP III-3 and III-1 strains expressed hyaluronate lysase activity; however, all III-2 strains lack hyaluronate lysase activity, because the gene that encodes hyaluronate lysase, hylB, is inactivated by IS1548. Subtractive hybridization was used to identify 9 short DNA sequences that are present in all the III-3 strains but not in any of the III-2 or III-1 strains. With 1 exception, these III-3-specific sequences were not detected in nonserotype III GBS. These data further validate the RDP-based subclassification of GBS and suggest that lineage-specific genes will be identified, which account for the differences in virulence among the lineages.
authors.affiliation: Department of Pediatrics, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA. john.bohnsack@hsc.utah.edu
authors.forename: J F
authors.initials: JF
authors.lastname: Bohnsack
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: S R
authors.initials: SR
authors.lastname: Detrick
authors.forename: L R
authors.initials: LR
authors.lastname: Pelinka
authors.forename: L L
authors.initials: LL
authors.lastname: Hammitt
authors.forename: A A
authors.initials: AA
authors.lastname: Aly
authors.forename: A A
authors.initials: AA
authors.lastname: Whiting
authors.forename: E E
authors.initials: EE
authors.lastname: Adderson
mesh_terms: D015139:Blotting, Southern; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D006801:Humans; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D011133:Polysaccharide-Lyases / Q000737:chemistry / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013291:Streptococcus / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D014774:Virulence / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes; D011133:Polysaccharide-Lyases; C100002:hyaluronate lyase