[Antibiotic sensitivity of Streptococcus pyogenes in pediatrics]. / Sensibilidad antibiótica de Streptococcus pyogenes en pediatría.

ABSTRACT

BACKGROUND: The purpose of this study was to set up the current level of Streptococcus pyogenes sensitivity, in pediatric patients in our community, to penicillin, clindamycin, clarithromycin, erythromycin and azithromycin. MATERIAL AND METHODS: 100 strains were collected between October 1996 to July 1997. 79 were pharyngeal and 21 were non-pharyngeal strains. The MICs were obtained by the E-test method, and furthermore the results were compared by the Kirby-Bauer method. RESULTS: All strains were sensitive to penicillin and except one (inducible resistance) to clindamycin. 19% were resistant to macrolide, without differences among clarithromycin, erythromycin and azithromycin. From 13 strains (16.5%) of pharyngeal and 6 (28.5%) from non-pharyngeal samples, 4 of these from cutaneous samples, showed resistance. 18 of the resistance strains belonged to novel resistance fenotip and one to 10 inducible fenotip. Only minor discrepancies about erythromycin and clindamycin were observed between E-test and Kirby-Bauer methods. CONCLUSIONS: This study confirms a remarkable level of resistance to macrolides in pediatric patients, mainly in the cutaneous samples. Due to the reduced prevalence of macrolide-susceptible strains, in vitro susceptibility testing appears necessary in case of macrolide chemotherapy.