Antimicrobial susceptibility of bacterial pathogens in the oropharynx of healthy children.

In a study to determine the prevalence and antimicrobial susceptibility of bacterial pathogens in the oropharynx of healthy children, throat swabs obtained from 1765 children were cultured and the organisms recovered tested by the disk diffusion method and the E test. Six hundred ninety-one children (39.1%) harbored Haemophilus influenzae, 112 (6.3%) Streptococcus pyogenes, 73 (4.1%) Moraxella catarrhalis, 52 (2.9%) Streptococcus pneumoniae, and 50 (2.8%) Neisseria meningitidis in their oropharynx. The rate of penicillin resistance was 2%, 0%, and 12%, respectively, for Streptococcus pneumoniae, Streptococcus pyogenes, and Neisseria meningitidis. Ampicillin resistance was observed in 8.6% of Haemophilus influenzae strains and 78% of Moraxella catarrhalis strains and was associated with the presence of beta-lactamase, except in one strain of Haemophilus influenzae. Five (4.4%) isolates of Streptococcus pyogenes were resistant to macrolides. The low level of resistance observed in this area contrasts with the high rates reported in the literature.