Molecular Basis for Erythromycin Resistance in Group A Streptococcus Isolated From Skin and Soft Tissue Infections.

Abstract

In recent years there has been an increase in the use of erythromycin in the treatment of infections caused by bacteria other than Group A Streptococcus (GAS), which has resulted in increased resistance to this antibiotic. Erythromycin and other macrolides are alternative agents for treating GAS infections in patients, who are allergic to penicillin and its derivatives. The main aim of this study was to identify frequency, pattern and genetic determinant of erythromycin resistance among the GAS isolated from skin and soft tissue infections. A total 100 isolates of GAS were screened for erythromycin resistance by phenotypic and genotypic method. The results of the present study showed that 38% isolates were resistant to erythromycin. The iMLS (inducible macrolide-lincosamide-streptogramin) phenotype was predominant (55.26%) followed by M phenotype (26.32%) and cMLS (constitutive macrolide-lincosamide-streptogramin) (18.42%). Phenotypic and genotypic analysis showed that the MLSB phenotype with ermB mediated mechanism of resistance was found the most common (76.31%) followed by mefA (20.51%). The ermTR genes was absent in all the isolates.