Resistance of Streptococcus pneumoniae (750) to penicillin, erythromycin, c
hloramphenicol and trimethoprim/sulfamethoxazole isolated in 4 Turkish hosp
itals between 1996 and 1999 was evaluated according to year of isolation, p
atients' age groups and specimen. Penicillin susceptibility was determined
by E-test strips and the other antibiotics were tested by disk diffusion te
st following the NCCLS guidelines in each center. Overall high and intermed
iate resistance to penicillin was 3% and 29%, respectively. There was a sig
nificant difference (p <0.001) between the centers with regard to penicilli
n resistance. However, there was no significant increase in resistance by y
ear. Penicillin resistance varied significantly among children and adults (
36% versus 25%) and according to the specimen. Highest rate of penicillin r
esistance was observed in respiratory specimens (36%) followed by ear exuda
tes (33.5%). In blood isolates, resistance to penicillin was 28.6%. Overall
resistance to erythromycin was 8%, to chloramphenicol 5% and to trimethopr
im-sulfamethoxazole 47%. Although overall penicillin resistance in these Tu
rkish S. pneumoniae isolates is high, resistance rates vary in each center
and have not increased from 1996 to 1999.