[Antibiotic resistance of clinical isolates Streptococcus pneumoniae]

Streptococcus pneumoniae is a major pathogenic organism of community-acquired bacterial pneumonia as well as otitis media and bacterial meningitis. Recently penicillin- or multiply resistant pneumococci have been isolated worldwide. In this study we examined the susceptibility tests of 11 antibiotics with the total of 63 clinically isolated pneumococci, using a broth microdilution method. Most of pneumococci were isolated from respiratory specimens. According to NCCLS standard, all these pneumococci were classified as follows: PCG-susceptible S. pneumoniae (PSSP, MIC < or = 0.06 micrograms/ml), PCG-intermediately resistant S. pneumoniae (PISP, 0.12 < or = MIC < or = 1.0 micrograms/ml), and PCG-highly resistant S. pneumoniae (PRSP, MIC > or = 2.0 micrograms/ml) were 45 (71.4%), 14 (22.2%) and 4 isolates (6.4%), respectively. Forty-four percent of isolates from children under 10 years and 29% from outpatients were PISP or PRSP. Resistance to erythromycin (EM) clindamycin (CLDM) or minocycline (MINO) was significantly recognized, but not correlated with that to PCG. On the other hand, the resistance to beta-lactam antibiotics were correlated with that to PCG. Seventeen isolates (27%) were resistant to two or more antibiotics among PCG, EM, MINO, ofloxacin (OFLX), and sulfamethoxazole-trimethoprim (ST). In pneumococcal infection, we always have to pay a careful attention to susceptibility test before we choose antibiotics.