Genetic commonality of macrolide-resistant group A beta hemolytic streptococcus pharyngeal strains

Angela L. Myers, Mary A. Jackson, Rangaraj Selvarangan, Richard V. Goering, Christopher Harrison

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background: Group A beta hemolytic streptococcus (GABHS) pharyngitis is a common childhood illness. Penicillin remains the gold standard therapy, but macrolides are indicated for the penicillin allergic patient, and are often used for convenience. Methods: We conducted a surveillance study of children with pharyngitis and positive streptococcal rapid antigen testing from 10/05 to 10/06 at 2 sites (A & B). Demographics, treatment, and resistance data was collected and compared to previous data from 2002. Erythromycin (EM) resistance was determined by disk diffusion and E-test on 500 isolates. Pulse field gel electrophoresis (PFGE) was performed to measure genetic relatedness of isolates. StatXact version 8 software (Cytel Inc., Cambridge, MA) was utilized to perform Fisher's exact test and exact confidence interval (CI) analysis. Results: There were no differences in resistance rates or demographic features, with the exception of race, between sites A & B. EM resistance was 0 in 2002, 3.5% in 2005-06 at site A, and 4.5% in 2005-06 at site B. 3/7 and 3/9 had inducible resistance at A and B respectively. 8 isolates had relatedness ≥80%, 5 of which were 88% homologous on PFGE. Conclusion: Community macrolide resistance has increased following increased macrolide use. These results may have treatment implications if use continues to be high.

Original languageEnglish (US)
Article number33
JournalAnnals of Clinical Microbiology and Antimicrobials
StatePublished - Dec 1 2009

All Science Journal Classification (ASJC) codes

  • Microbiology (medical)
  • Infectious Diseases


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