title: Genetic diversity and virulence properties of Streptococcus dysgalactiae subsp. equisimilis from different sources.
abstract: A recent increase in virulence of pathogenic Streptococcus dysgalactiae subsp. equisimilis (SDSE) has been widely proposed. Such an increase may be partly explained by the acquisition of new virulence traits by horizontal gene transfer from related streptococci such as Streptococcus pyogenes (GAS) and Streptococcus agalactiae (GBS). A collection of 54 SDSE strains isolated in Italy in the years 2000-2010 from different sources (paediatric throat carriage, invasive and non-invasive diseases) was characterized by emm typing and pulsed-field gel electrophoresis (PFGE) analysis. The virulence repertoire was evaluated by PCR for the presence of GAS superantigen (spe) genes, the streptolysin S (sagA) gene, the group G fibronectin-binding protein (gfbA) gene and GAS-GBS alpha-like protein family (alp) genes; moreover, the ability to invade human epithelial cells was investigated. Resistance to tetracycline, erythromycin and clindamycin was assessed. The combined use of emm typing and PFGE proved to be a reliable strategy for the epidemiological analysis of SDSE isolates. The most frequent emm types were the same as those more frequently reported in other studies, thus indicating the diffusion of a limited number of a few successful emm types fit to disseminate in humans. The speG gene was detected in SDSE strains of different genetic backgrounds. Erythromycin resistance determined by the erm(T) gene, and the unusual, foggy MLSB phenotype, observed in one and seven strains, respectively, have never previously, to our knowledge, been reported in SDSE. Moreover, a new member of the alp family was identified. The identification of new antibiotic and virulence determinants, despite the small size of the sample analysed, shows the importance of constant attention to monitoring the extent of lateral gene transfer in this emerging pathogen.
authors.affiliation: Dipartimento di Centro Integrato di Ricerca (CIR), Università Campus Bio-Medico, Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gherardi
authors.affiliation: Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Imperi
authors.affiliation: Dipartimento di Scienze Biomediche e Sanità Pubblica, Sezione Microbiologia, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Palmieri
authors.affiliation: Dipartimento di Scienze Biomediche e Sanità Pubblica, Sezione Microbiologia, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Gloria
authors.initials: G
authors.lastname: Magi
authors.affiliation: Dipartimento di Scienze Biomediche e Sanità Pubblica, Sezione Microbiologia, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Bruna
authors.initials: B
authors.lastname: Facinelli
authors.affiliation: Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Lucilla
authors.initials: L
authors.lastname: Baldassarri
authors.affiliation: Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Pataracchia
authors.affiliation: Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Creti
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000942:Antigens, Bacterial / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D002353:Carrier State / Q000382:microbiology*; D002460:Cell Line; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004705:Endocytosis; D004847:Epithelial Cells / Q000382:microbiology; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007558:Italy / Q000453:epidemiology; D017720:Molecular Epidemiology; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013291:Streptococcus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D037521:Virulence Factors; C014689:streptococcal M protein