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Serotype profile and antibiotyping of Streptococcus pneumoniae strains isolated from nasal carriage in pediatric patients

Abstract:

The aim of this study was to determine the serotype profile and antibiotyping of Streptococcus pneumoniae from nasal isolates in children. Nasopharyngeal swab samples obtained from 125 children were cultivated and screened for the presence of S. pneumoniae. Strains were identified according to standard microbiological methods. The isolates were serotyped by the Quellung reaction and resistance patterns were determined by the microdilution method according to NCCLS guidelines. Results indicate an overall pneumococcal carriage rate of 24% (n=30). The most commonly isolated serotypes were 23F (20%), 6B (20%) and 14 (13%). 73% of isolates were resistant at least to one of the tested antibiotics. 47% of the strains were consistently resistant to penicillin and the serotypes 6B and 23F were frequently associated with this marker. 60% of the strains were resistant to doxycycline, 37% to trimethoprim/sulfamethoxazole and clindamycin, 30% to erythromycin, 23% to cloramphenicol, 7% to ceftriaxone and 3% to cefepime. All strains were sensible to ofloxacin, rifampin and vancomycin. The most common combined resistance patterns were PNC-ERI-TMP/SMX-DOX-CLO-CLI (16.59%) and PNC-DOX (13.27%). The results obtained in this study will allow to orient the empiric therapy for pneumococcal infections and a rational use of antibiotics in clinical practice, as well as the application of an appropriate vaccination program specially adapted to the serotypes more frequently found in children. © 2006 Univarsidad del Zulia.