title: Molecular typing of erythromycin-resistant streptococcus pyogenes strains with the M phenotype isolated in Italy.
abstract: To assess the spread of the new M phenotype, various erythromycin-resistant Streptococcus pyogenes strains from three Italian cities (Verona, Monza, Florence) were characterised. Each strain was analysed for the presence of genes ermAM and mefA, for the ability to accumulate radioactive erythromycin in the absence of sodium arsenate, for the protein T serological type, and for the DNA macrorestriction profile identified by means of pulsed-field gel electrophoresis. In a number of strains, the presence of the inducible ermAM gene was demonstrated; all these strains were negative in the efflux-pump detection assay, did not possess the mefA gene, and had similar restriction profiles. The strains with the efflux mechanism and mefA gene belonged to different serotypes. Of these, only one serotype, T4, was isolated in all three cities. The restriction profile analysis with SmaI and SfiI revealed a very close correlation between strains with the same serotype.
authors.affiliation: Institute of Microbiology, University of Verona, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Valisena
authors.forename: C
authors.initials: C
authors.lastname: Falci
authors.forename: A
authors.initials: A
authors.lastname: Mazzariol
authors.forename: G
authors.initials: G
authors.lastname: Cornaglia
authors.forename: C E
authors.initials: CE
authors.lastname: Cocuzza
authors.forename: P
authors.initials: P
authors.lastname: Nicoletti
authors.forename: R
authors.initials: R
authors.lastname: Rescaldani
authors.forename: R
authors.initials: R
authors.lastname: Fontana
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins; D015373:Bacterial Typing Techniques; D004352:Drug Resistance, Microbial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D004917:Erythromycin / Q000494:pharmacology*; D006801:Humans; D007558:Italy; D008565:Membrane Proteins / Q000235:genetics*; D008780:Methyltransferases / Q000235:genetics*; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000145:classification / Q000187:drug effects / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C117866:MefA protein, Streptococcus; D008565:Membrane Proteins; D004917:Erythromycin; D008780:Methyltransferases; C035181:rRNA (adenosine-O-2'-)methyltransferase