title: Genotyping of erythromycin resistant group C & G streptococci isolated in Chennai, south India.
abstract: OBJECTIVE
  Increasing resistance to erythromycin has been observed worldwide in group C and group G streptococci (GCS/GGS). The information available from India is scanty. The aim of the study was to identify erythromycin resistant GCS/GGS isolates in Chennai, south India, and to compare erythromycin resistant genotypes with emm types.
  
  
  METHODS
  One hundred and thirty one GCS/GGS isolates were tested for erythromycin resistance by disc diffusion and agar dilution methods. Erythromycin resistance genotypes [erm(A), erm(B) and mef(A)] were determined by a multiplex PCR. emm types of erythromycin resistant GCS/GGS isolates was also assessed using emm gene sequencing method.
  
  
  RESULTS
  Sixteen of the 131 isolates (12.21%) were resistant to erythromycin. Majority of the isolates were GGS (15/16). Eight of the 16 (50%) were S. dysgalactiae subsps. equisimilis. Twelve isolates (75%) were MLS B phenotype and four (25%) were M phenotype. Of the 12 isolates which exhibited MLS B resistance, seven showed cMLS B phenotype and were positive for erm(B) gene. The remaining five were iMLS B phenotype of which three were positive for erm(A) gene and two for erm(B) gene. erm(A) was common among carriers whereas erm(B) was common among clinical isolates.
  
  
  CONCLUSIONS
  MLS B was the predominant phenotype and erm(B) was the common genotype in the present study. The emm type stC1400.0 was frequently associated with erythromycin resistant GCS/GGS in our study.
authors.affiliation: Department of Microbiology, Dr A.L. Mudaliar Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India.
authors.forename: D
authors.initials: D
authors.lastname: Prabu
authors.forename: Thangam
authors.initials: T
authors.lastname: Menon
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004917:Erythromycin / Q000627:therapeutic use*; D005838:Genotype; D006801:Humans; D007194:India; D008826:Microbial Sensitivity Tests; D013290:Streptococcal Infections / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D013291:Streptococcus / Q000235:genetics* / Q000472:pathogenicity; D013296:Streptococcus pneumoniae
chemical_list: D000900:Anti-Bacterial Agents; D004917:Erythromycin