Characterisation of the main clones of Streptococcus pyogenes carrying the ermA (subclass TR) gene in Spain

Abstract

Seventy-four Streptococcus pyogenes isolates showing the macrolide–lincosamide–streptogramin B (MLS B) resistance phenotype carrying the ermA gene (72 of which showed the inducible resistance phenotype) were obtained between 1999 and 2004. Seven different sequence types (STs) and emm types were detected: emm22/ST46 ( n = 33); emm77/ST63 ( n = 22); emm73/ST331 ( n = 10); emm94/ST89 ( n = 6); and one isolate each of emm28/ST52, emm11/ST403 and emm4/ST38. All ST46 isolates were susceptible to tetracycline and almost all reacted against the T12 type (all agglutinated into the T-pattern 3/12/13/B3264). Resistance to tetracycline was observed in all ST63 ( tetO+) and ST89 ( tetM+) isolates. Most of the ST63 isolates reacted against the T28 type (all agglutinated into the T-pattern 9/13/28). The 74 isolates were grouped into eight pulsed-field gel electrophoresis pulsotypes (one cluster for each emm/ST type, except for emm77/ST63).