Group A streptococcal genotypes from pediatric throat isolates in Rome, Italy

In a study assessing genetic diversity, 114 group A streptococcus (GAS) iso lates were recovered from pediatric pharyngitis patients in Rome, ItaIy. Th ese isolates comprised 22 different M protein gene (emm) sequence types, 14 of which were associated,vith a distinct serum opacity factor/fibronectin binding protein gene (sof) sequence type. Isolates with the same emm gene s equence type generally shared a highly conserved chromosomal macrorestricti on profile. In three instances, isolates with dissimilar macrorestriction p rofiles had identical emm types; in each of these cases multilocus sequence typing revealed that isolates with the same emm type were clones having th e same allelic profiles. Ninety-eight percent of the pharyngeal isolates ha d emm types previously found to be highly associated,vith mga locus gene pa tterns commonly found in pharyngeal GAS isolates.