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.
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.
Bohnsack
J F
JF
Department of Pediatrics, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA. john.bohnsack@hsc.utah.edu
Takahashi
S
S
Detrick
S R
SR
Pelinka
L R
LR
Hammitt
L L
LL
Aly
A A
AA
Whiting
A A
AA
Adderson
E E
EE
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
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes; D011133:Polysaccharide-Lyases; C100002:hyaluronate lyase