Fig. 1. Two major mechanisms of macrolide resistance in group A Streptococcus: active drug efflux mediated by mef genes (left) and target-site modification mediated by erm genes through methylation of 23S rRNA within the 50S ribosomal subunit (right). MLSB, macrolide-lincosamide-streptogramin B resistance phenotype.

Ann Clin Microbiol 2026;29(3):11. Molecular mechanisms, epidemiology, and clinical implications of macrolide resistance in group A Streptococcus: a narrative review

Fig. 1. Two major mechanisms of macrolide resistance in group A Streptococcus: active drug efflux mediated by mef genes (left) and target-site modification mediated by erm genes through methylation of 23S rRNA within the 50S ribosomal subunit (right). MLS_B, macrolide-lincosamide-streptogramin B resistance phenotype.