serotype profile and antibiotyping of streptococcus pneumoniae strains isolated from nasal carriage in pediatric patients 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 trimethoprimsulfamethoxazole 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 pnceritmpsmxdoxclocli 1659 and pncdox 1327 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