Clonal Differences among Erythromycin-Resistant Streptococcus pyogenes in Spain

Survey of emm Gene Sequences from Pharyngeal Streptococcus pyogenes Isolates Collected in Spain and Their Relationship with Erythromycin Susceptibility

“…Our results are in agreement with those of a previous study conducted by Pérez-Trallero et al in Spain (20). In that study, erythromycin-resistant GAS isolates from Spain (n ϭ 437, 1988 to 1997) were composed mainly of two clones designated clone B (emm type 4) and clone D (emm type 75) that were already isolated in Spain in 1991.…”

“…Our results show that a few M types were responsible for up to 85% of the erythromycinresistant isolates, suggesting that few clones caused this phenomenon. This hypothesis was supported by the fact that the M phenotype was the most common resistance mechanism, a feature previously reported by other authors (20,23). However, genetic divergence among strains sharing the same emm gene sequence has been reported (5,6,17,29).…”

“…In addition to emm type 4, emm type st1815 accounted for 20% of the GAS resistant to erythromycin. This emm type was not detected by Pérez-Trallero et al in their study, where they assayed only 14 emm types (20); however, it was one of the prevalent types in our study. Interestingly, the most common PFGE and ribotype pattern among st1815 emm type strains was identical to that of emm type 75 strains.…”

“…Resistance to erythromycin remained at low levels among S. pyogenes in most countries of the world (14); however, in the last years, a significant increase in erythromycin-resistant isolates in different countries has been reported (15,20,22,23). In most of these studies, resistance to erythromycin was caused by a few clones and the mechanisms of resistance were mainly based on the presence of an active drug efflux by pumps encoded by the gene mefA (M phenotype) that take out of the cells 14-and 15-membered macrolides (25).…”

The M protein of group A Streptococcus is a key virulence factor and a clinically relevant strain identification marker

“…A strong association between erythromycin (or other macrolide) resistance has been shown for M4, M6, M12 and M75-members of this small group are responsible for much of the observed macrolide resistance in surveys of GAS isolates from the US, 44,49,50 Belgium, 51 Greece 52 and Spain. 53,54 In general, the majority of isolates of these types are found to be resistant, while only scattered isolates of other serotypes exhibit the same resistance phenotype-with some local exceptions, such as the dominance of M2 among erythromycin resistant isolates in Italy. 55 In some cases, specific clones of a given serotype have been responsible for the spread of multiple resistance phenotypes derived from specific resistance cassettes-for example the spread of an erythromycin and tetracycline resistant clone of M77 [carrying the tet(O) determinant] in Italy, Norway and Denmark.…”