Increased carriage of resistant non-pneumococcal α-hemolytic streptococci after antibiotic therapy

F. Ghaffar, I. R. Friedland, K. Katz, L. S. Muniz, J. L. Smith, P. Davis, J. Reynolds, Jr McCracken G.H.

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Objective: We compared colonization and resistance rates of non- pneumococcal α-hemolytic streptococci (AHS) and Streptococcus pneumaniae in children receiving antibiotic therapy for acute otitis media. Study design: Between December 1997 and September 1998, children 6 months to 6 years of age, diagnosed with acute otitis media were randomly assigned to receive amoxicillin/clavulanate (Augmentin) 45 mg/kg/d in 2 divided doses for 10 days or azithromycin (Zithromax), 10 mg/kg, once on the first day, followed by 5 mg/kg daily for 4 days. Nasopharyngeal swabs for culture were obtained before and at 2 weeks and 2 months after the start of therapy. Streptococci were identified by species, and antibiotic susceptibility was determined by the epsilometric test. Results: One hundred six children completed the 2-week follow-up and 2-month follow-up, respectively. The nasopharyngeal carriage rate of nonpneumococcal AHS increased from 14% before treatment to 32% at the 2-week follow-up (P = .02) and was similar in both treatment groups. In contrast, the carriage of S pneumoniae decreased from 51% before therapy to 27% at the 2-week follow-up (P = .002). The carriage of penicillin-resistant AHS strains (minimum inhibitory concentration > 1 μg/mL) increased from 9% before treatment to 26% at 2 weeks and 36% at 2 months. Conclusions: Amoxicillin/clavulanate and azithromycin therapy resulted in increased isolation of nasopharyngeal non-pneumococcal AHS, many of which were multidrug-resistant, in contrast to a decrease in pneumococcal carriage. This suggests that the competitive balance between these 2 groups of organisms was disturbed as a result of differential antibiotic susceptibility. The importance of drug-resistant AHS as a reservoir for resistance genes for S pneumoniae warrants further investigation.

Original languageEnglish (US)
Pages (from-to)618-623
Number of pages6
JournalJournal of Pediatrics
Volume135
Issue number5
DOIs
StatePublished - Jan 1 1999

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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