title: Distribution and sequence variations of selected virulence genes among group A streptococcal isolates from western Norway.
abstract: In order to compare the distribution of selected virulence genes among group A streptococci recovered from invasive disease and superficial infections, 42 isolates were screened for mga, speB, speA, ssa and ska, by PCR. The isolates were predominantly of the sequence types emm1, emm3 and emm6, but also included a few of the types emm22, emm28, emm75 and emm78. The phage-mediated speA seemed to be prevalent in emm types 1 and 3, and its distribution was not related to disease severity. The other genes were present in all isolates. The mga, speB and speA were further studied by sequence analysis. Although allotypic associations with invasiveness were not found, allelic specificity to the emm sequence type was observed. In addition, the mga sequences indicated two lineages, related to opacity factor production. A possible recombination between these two main divergent mga genes was observed in isolates of the types emm22 and emm75. A logical nomenclature of the alleles of mga and speB is suggested.
authors.affiliation: Department of Microbiology and Immunology, The Gade Institute, Bergen, Norway. Haima.Mylvaganam@cih.uib.no
authors.forename: H
authors.initials: H
authors.lastname: Mylvaganam
authors.forename: B
authors.initials: B
authors.lastname: Bjorvatn
authors.forename: A
authors.initials: A
authors.lastname: Osland
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics; D005098:Exotoxins; D019115:Fasciitis, Necrotizing / Q000382:microbiology; D005798:Genes, Bacterial; D014644:Genetic Variation; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D009664:Norway; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D012772:Shock, Septic / Q000382:microbiology; D013290:Streptococcal Infections / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000235:genetics* / Q000472:pathogenicity*; D009626:Terminology as Topic; D014774:Virulence / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D005098:Exotoxins; D008565:Membrane Proteins; C117980:SpeA protein, Streptococcus pyogenes; C014689:streptococcal M protein; C068267:mry protein, Streptococcus pyogenes; D003546:Cysteine Endopeptidases; C042477:streptopain