Antimicrobial Resistance and Serotype Distribution of Streptococcus pneumoniae Strains in Central Taiwan

Background. Antibiotic resistance and serotype distribution of Streptococcus pneumoniae have grown in importance due to the treatment and vaccine policy for pneumococcal infection in Taiwan. Methods. From January 1998 through December 1999, we studied the susceptibilities and serotypes of 77 pneumococcal strains isolated in central Taiwan. Typing was carried out using detection of quellung reactions with antisera provided by the Staten Seruminstitut (Copenhagen, Denmark). All strains were initially screened for susceptibility to antimicrobial agents using the disk diffusion method d to penicillin using the E test method on Mueller-Hinton agar plates with 5% defibrinated sheep blood. Results. Resistance rates were penicillin, 68%; erythromycin, 88%; tetracycline, 96%; chloramphenicol, 38%; vancomycin, 0%; cefotaxime, 0%; ceftriaxone, 0%; and trimethoprim/sulfamethoxazole, 71%. The serotypes were 23 (24%), 14 (18%), 6 (17%), 9 (9%), 19 (8%), 3 (8%), 4(5.%), 33 (3%), 15(1%),10 (1%), 17 (1%),18 (1%), and 20 (1%). Multiple drug resistance was associated with predominant serotypes of 23 (90%), 14 (92%), 6 (92%), 9 (100%), 19 (100%), 3 (67%), and 4(50%). Nearly 97% of all pneumococcal strains isolated in this surveillance belonged to one of the 21 different types or groups represented in the 23 valent-pneumococcal vaccine. Conclusions. Resistances to the tested antibodies were more common among intermediate penicillin-resistant isolate than among penicillin-susceptible isolates. Antimicrobial resistance among S. pneumoniae has become a serious problem. In addition, the 23-valent pneumococcal vaccine provided the potential efficacy for prevention of pneumococcal infections.