Nasopharyngeal carriage of antibiotic-resistant pneumococci by children in group day care.

We compared rates of antibiotic resistance in strains of Streptococcus pneumoniae recovered from nasopharyngeal secretions of a group of children studied longitudinally in a research day care center between 1978 and 1985 and recovered from usually sterile body fluids of patients at a tertiary care hospital between 1981 and 1985. The prevalence of trimethoprim-sulfamethoxazole (TMP-SMZ) resistance was 11.5% in isolates from the hospital, whereas 30.0% of episodes of nasopharyngeal carriage of S. pneumoniae studied in day care children included TMP-SMZ-resistant isolates. The proportion of episodes of colonization with TMP-SMZ-resistant isolates in the day care study increased from 5.4% before 1981 to 39% between 1981 and 1985. Isolates of S. pneumoniae relatively resistant (MIC greater than or equal to 0.125 micrograms/mL) to penicillin G, amoxicillin, or cefuroxime accounted for 8% of isolates from the hospital and 11.9% of episodes of nasopharyngeal colonization in children in day care. Pneumococci with reduced susceptibility to either TMP-SMZ or a beta-lactam antibiotic were recovered from 68% of 72 children in the day care study.