Identification of a Novel Insertion Element, IS1548, in Group B Streptococci, Predominantly in Strains Causing Endocarditis

• Published in: The Journal of infectious diseases 1998-04, Vol.177 (4), p.967-976
• Main Authors: Granlund, Margareta, Öberg, Linda, Sellin, Mats, Norgren, Mari
• Format: Article
• Language: English
• Subjects: Adhesins, Bacterial; Adult; Amino Acid Sequence; Bacteriology; Base Sequence; Biological and medical sciences; Blood; Chromosome Mapping; Cloning, Molecular; DNA; DNA Transposable Elements - genetics; DNA, Bacterial - analysis; DNA, Bacterial - genetics; Electrophoresis, Gel, Pulsed-Field; Endocarditis; Endocarditis, Bacterial - genetics; Endopeptidases - genetics; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Genes; Genetics; Humans; Hyaluronoglucosaminidase - genetics; Hyaluronoglucosaminidase - metabolism; Infections; Major Articles; Microbiology; Molecular Sequence Data; Nucleotide sequences; Nucleotides; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Repetitive Sequences, Nucleic Acid; Sequence Analysis, DNA; Streptococcal Infections - genetics; Streptococcus agalactiae; Streptococcus agalactiae - genetics; Streptococcus agalactiae - immunology; Streptococcus agalactiae - metabolism; Streptococcus pneumoniae - genetics; Streptococcus pyogenes - genetics; Transposons
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1086/515233

Hyaluronidase has been postulated to be a virulence factor in group B streptococci (GBS). No hyaluronidase activity was found in 15 of 50 GBS isolates from adults studied. Most of these hyaluronidase-negative strains belonged to serotype III. In strains lacking hyaluronidase activity, an insertion of 1317 nucleotides was found in the hyaluronidase gene. The fragment was cloned and sequenced and found to have characteristics of a novel insertion sequence, designated IS1548. As well as in GBS serotype III, this sequence was found in 3 of 6 serotype II isolates and in all 10 group A streptococcal strains (GAS) tested. Homologies were found with repeated sequences in Streptococcus pneumoniae and with H repeats in Escherichia coli. All GBS strains harboring IS1548 and some GAS strains had one copy of IS1548 located downstream of the C5a peptidase gene. IS1548 was present in 9 of 13 GBS isolates from blood in endocarditis patients and in 3 of 22 vaginally colonizing strains.