ICE Spy 009, a Conjugative Genetic Element Carrying mef (E) in Streptococcus pyogenes

Efflux-mediated macrolide resistance due to mef (E) and mel , carried by the mega element, is common in Streptococcus pneumoniae , for which it was originally characterized, but it is rare in Streptococcus pyogenes . In S. pyogenes , mega was previously found to be enclosed in Tn 2009 , a composite genetic element of the Tn 916 family containing tet (M) and conferring erythromycin and tetracycline resistance. In this study, S. pyogenes isolates containing mef (E), apparently not associated with other resistance determinants, were examined to characterize the genetic context of mega. By whole-genome sequencing of one isolate, MB56Spyo009, we identified a novel composite integrative and conjugative element (ICE) carrying mega, designated ICE Spy 009, belonging to the ICE Sa 2603 family. ICE Spy 009 was 55 kb long, contained 61 putative open reading frames (ORFs), and was found to be integrated into hylA , a novel integration site for the ICE Sa 2603 family. The modular organization of the ICE was similar to that of members of the ICE Sa 2603 family carried by different streptococcal species. In addition, a novel cluster of accessory resistance genes was found inside a region that encloses mega. PCR mapping targeting ICE Spy 009 revealed the presence of a similar ICE in five other isolates under study. While in three isolates the integration site was the same as that of ICE Spy 009, in two isolates the ICE was integrated into rplL , the typical integration site of the ICE Sa 2603 family. ICE Spy 009 was able to transfer macrolide resistance by conjugation to both S. pyogenes and S. pneumoniae , showing the first evidence of the transferability of mega from S. pyogenes .