PENICILLIN-RESISTANT AND MULTIDRUG-RESISTANT STREPTOCOCCUS-PNEUMONIAEIN A PEDIATRIC HOSPITAL IN ZAGREB, CROATIA

Sixty-four penicillin-resistant Streptococcus pneumoniae isolates [ben zylpenicillin minimal inhibitory concentrations (MICs) between 0.05 an d 1.6 mu g/ml] recovered at the Pediatric Hospital ''Dr. Fran Mihaljev ic'' in Zagreb, Croatia between October 1990 and March 1993 were analy zed for serotype, antibiotic susceptibility patterns, and chromosomal relatedness using pulsed-field gel electrophoretic (PFGE) analysis of chromosomal DNA fragmented by digestion with the SmaI endonuclease, Ho spital ''Dr. Fran Mihaljevic'' services the capital of Croatia and its vicinity, Most of the isolates were from nasopharyngeal carriage, but several isolates were from otitis media, sinusitis, and meningitis, M ost isolates belonged to either serotype 23F (36/64) or 19F (12/64); t he rest, including three 15C isolates, were in 11 additional distinct serotypes, The overwhelming majority (25/36) of the serotype 23F isola tes had penicillin MIC values of 1-2 mu g/ml and shared variants of a common PFGE pattern, closely related to the PFGE identified in multire sistant pneumococci of the same serotype with wide geographic spread t o Spain, Portugal, France, and the United States, This group of bacter ia was also resistant to tetracycline, chloramphenicol, and sulfametho xazole/trimethoprim. In contrast to the relative genetic and phenotypi c homogeneity of the more highly penicillin resistant isolates, pneumo cocci with penicillin MICs between 0.5 and 0.4 mu g/ml (29/64) were di stributed in 13 different serotypes and as many as 20 distinct PFGE pa tterns.