There are 84 serotypes of Streptococcus pneumoniae by the antigenicity of capsular polysaccharide, and the prevalence of penicillin-resistant pneumococcal infections is increasing in the many parts of the world. In order to determine the
serotypes
and
assess the prevalence of antibiotic resistance of S. pneumoniae in Korea, 131 strains were studied in regard to serotypes and minimum inhibitory concentration (MIC) with 10 kinds of antimicrobial agents including penicillin by agar dilution
method.
The
serotype was determined at the Statens Seruminstitut (Copenhagen, Denmark). They were isolated from lower respiratory tract specimens (64), normally-sterile body fluids (32; cerebrospinal fluid, blood and ascites), etc. during 26 month-period
over
1991-1993 at the Seoul National University Hospital. Twenty seven different serotypes were identified, serotypes 6A, 6B, 14, 19F and 23F accounting for 67%. Strains from normally-sterile body fluids were distributed among 12 different serotypes
and
serotypes 19F and 23F were the most frequently encountered. Seventy percent of all isolates were nonsusceptible to penicillin; either intermediate (0.1≤MIC≤1㎍/ml, 37%) or high level (2.0㎍/ml ≤MIC, 33%) resistance. Eighty two percent of 75
strains
from the children less than 16 years of age and 59% of 32 from normally-sterile body fluids were penicillin-resistant. Serotypes of 14, 19F and 23F, strains isolated while on antimicrobial therapy, from children, from inpatients and nosocomially
acquired strains, were associated with significantly higher resistance rates. There was a good correlation between oxacillin disk diffusion test and MIC values of penicillin (agreement rate; 0.95). None of the resistant strains showedβ-lactamase
activity. Varying proportion of the penicillin-resistant strains showed associated resistance to cefaclor (89%), erythromycin (52%), chloramphenicol (34%), ciprofloxacin (15%), but none to cefotaxime, teicoplanin or vancomycin. We conclude that
all
clinically-significant isolates of S. pneumoniae should be bested for antimicrobial susceptibility, and alternatives other than penicillin may have to be used for empirical treatment for suspected pneumococcal infections in selected populations.
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