Rapid Inversion of the Prevalences of Macrolide Resistance Phenotypes Paralleled by a Diversification of T and emm Types among Streptococcus pyogenes in Portugal C. Silva-Costa, M. Ramirez, * J. Melo-Cristino, and the Portuguese Surveillance Group

T12/emm22 MLSB isolates could partially explain the drop in this phenotype, but the rise of the M phenotype was not due to clonal expansion. Although penicillin remains the antibiotic of choice in the treatment of Lancefield group A streptococci (GAS) infec-tions, macrolides and lincosamides are recommended as suit-able alternatives for patients allergic to penicillin (5). Newer macrolides, such as azithromycin, may be given once a day, making this an attractive option for the treatment of pharyn-gitis due to Streptococcus pyogenes. In Portugal, where penicil-lin V is not available, macrolides and lincosamides have the additional advantage of being a therapeutic option with an oral route of administration. High macrolide resistance in GAS was previously identified in Portugal (13) in line with other Euro-pean countries (1, 4, 6) but in contrast to others (14, 16). The aims of this study were to determine the prevalence of macro-lide resistance phenotypes and its temporal trends and to eval-uate the correlation with T and emm-types. A total of 1,321 GAS from clinical infections were collected from 30 laboratories, geographically distributed throughou