Epidemiology of penicillin resistance in Streptococcus pneumoniae isolatesin Kayseri, Turkey

Objective To determine the penicillin resistance and serotype distribution of Streptococcus pneumoniae strains and to identify clonal relationships of isolates resistant to penicillin by means of pulsed-field gel electrophore sis (PFGE). Methods In total, 193 S. pneumoniae strains were isolated froth clinical sp ecimens between November 1997 and January 2000. Susceptibility testing was carried out by E test, and serotyping by the Quellung reaction. Clonal rela tionship was analyzed by using PFGE with smaI endonuclease. Results Of the S. pneumoniae isolates, 23% were intermediately resistant to penicillin. There were no high-level resistant pneumococci. The majority o f isolates intermediately resist-ant to penicillin were of serogroups/serot ypes 19, 23, 14 and 1, in descending order of frequency. There were eight m ajor clones in strains intermediately resistant to penicillin. It was seen that serogroups in the 23-valent polysaccharide vaccine, 7-valent, 9-valent , and 11-valent vaccine formulations caused 92%, 75%, 78% and 87% of pneumo coccal diseases in our region, respectively. Conclusion Penicillin resistance in S. pneumoniae is relatively uncommon in Kayseri. All vaccine formulations can prevent the majority of pneumococcal diseases, and there is genetic heterogeneity in intermediately penicillin- resistant pneumococci in this region.