Prevalence and patterns of resistance of Streptococcus pneumoniae strains isolated from carriers attending day care centers in the area of Athens

The prevalence and patterns of Streptococcus pneumoniae resistance to antibiotics was examined in 146 nasopharyngeal carrier strains obtained during April and May, 1997, from 382 healthy children attending eight day care centers (DCCs) in the area of Athens. Reduced susceptibility to at least one antibiotic was found in 32.6% as follows: penicillin 11.4% (intermediate), cefotaxime 0.8% (intermediate), trimethoprim-sulfamethoxazole 22.7%, erythromycin 13.6%, tetracycline 11.4%, chloramphenicol 8.3%. Most of the nonsusceptible to penicillin isolates belonged to serogroups 23, 9, and 19. Multidrug resistance was detected in 11.4% of S. pneumoniae isolates including five penicillin nonsusceptible serogroup 23 strains. More than half of the multidrug resistant strains were susceptible to penicillin and belonged to serogroups 6 (4), 23 (1), 19 (1), and 1(1). Strains that belonged to the same serogroup/serotype and had identical resistance patterns appeared to cluster in some DCCs. Antibiotic use in the previous month was associated with reduced susceptibility to penicillin (p = 0.007) and multidrug resistance (p = 0.012). In conclusion, a moderate prevalence of reduced susceptibility to penicillin in pneumococcal carrier strains was found in our community. Multidrug resistance was common and was often associated with susceptibility to penicillin. Several distinct patterns of resistance were observed, suggesting the spread of resistant clones to our country.