Molecular characterization and allelic distribution of the phage-mediated hyaluronidase genes hylP and hylP2 among Group A streptococci from western Norway

Forty-two isolates of group A streptococcus from patients with invasive and non-invasive diseases in western Norway, belonging to the emm sequence typ es emm1, emm3, emm6, emm22, emm28, emm75 and emm78 were screened by PCR for the phage-mediated hyaluronidase genes hylP and hylP2. The amplified genes were characterized by nucleotide sequencing and/or by PCR-RFLP, with the o bjective of looking for possible associations between alleles of these two genes and invasiveness. The hylP was amplified from all isolates and two ma in alleles were found: hylP-emm3 in all emm3 isolates and hylP-emm6A in all emm6 isolates, the latter possibly generated by an intergenic recombinatio n between hylP and hylP2. The isolates of the other sequence types had eith er of these two alleles, or both. Only 27 isolates gave amplicons of the ap propriate size with the primers targeting hylP2. Sequencing of these amplic ons showed two main types: one was similar to the published hylP2 and the o ther (hylP-emm6B) was probably a variant of hylP. PCR-RFLP revealed the pre sence of both hylP-emm6B and hylP2 in at least six of the emm6 isolates. Th e alleles of both hylP and hylP2 seemed to have emm sequence type preferenc es. No association between invasiveness and specific phage-mediated hyaluro nidase genes/alleles or the production of extracellular hyaluronidase was o bserved. (C) 2000 Academic Press.