Characterization of erythromycin resistance of Streptococcus pyogenes isolated from pharyngitis patients in Korea.

Six hundred fifteen isolates of Streptococcus pyogenes were collected over a 6-year period from patients with pharyngitis in Korea. All isolates were characterized in terms of their antibiotic resistance, the phenotypes of erythromycin resistance, the frequencies of erm(B), erm(A), and mef(A) genes, and the emm genotype. The prevalent emm genotypes were emm12 and emm4. Moreover, the emm12 genotype was found to be the most resistant strain to erythromycin. Among the 126 strains demonstrating resistance to erythromycin, those with erm(B) were the most prevalent, accounting for 64.3% of the total. In summary, it is suggested that the S. pyogenes pathogen isolated from pharyngitis patients in Korea developed resistant gene acquisition, as well as a resistant phenotype, according to the annual prevailing emm type. It is also suggested that the emm genotype distribution of erythromycin-resistant strains is correlated to the acquisition of resistant genes.