Genetic and phenotypic features of Streptococcus pyogenes strains isolatedin Brazil that harbor new emm sequences

In the present study, 37 group A Streptococcus (GAS) strains belonging to 1 3 new emm sequence types identified among GAS strains randomly isolated in Brazil were characterized by using phenotypic and genotypic methods. The ne w types were designated st204, st211, st213, st809, st833, st854, st2904, s t2911, st2917, st2926, st3757, st3765, and st6735. All isolates were suscep tible to the antimicrobial agents tested, except to tetracycline. They all carried the speB gene, and 94.6% produced detectable SpeB. Most strains bel onging to a given emm type had similar or highly related pulsed-field gel e lectrophoresis profiles that were distinct from profiles of strains of anot her type. The other characteristics were variable from isolate to isolate, although some associations were consistently found within some emm types. U nlike the other isolates, all type st213 isolates were speA positive and pr oduced SpeA. Strains belonging to st3765 were T6 and opacity factor (OF) ne gative. Individual isolates within OF-positive emm types were associated wi th unique sof gene sequence types, while OF-negative isolates were sof nega tive by PCR. This report provides information on new emm sequence types fir st detected in GAS isolates from a geographic area not extensively surveyed . Such data can contribute to a better understanding of the local and globa l dynamics of GAS populations and of the epidemiological aspects of GAS inf ections occurring in tropical regions.