The relationship between serotypes and PFGE genotypes in isolates of Streptococcus pneumoniae from Hungary

The relatedness of 112 penicillin-non-susceptible isolates of Streptococcus pneumoniae from Hungary was determined by pulsed-field gel electrophoresis (PFGE), serotyping and antibiotic susceptibility tests. The differences in PFGE patterns closely mirrored the changes in resistance. Some genotypes comprised multiple serotypes, and the genetic diversity among certain serotypes was considerable. Generally, serotyping alone was insufficient for epidemiological mapping of pneumococcal isolates. There was considerable serotype diversity, but the five most frequent international serotypes (6, 9, 14, 23, 19) were the most prevalent. In addition, the presence of some well-defined resistant international pneumococcal clones in the Hungarian population was identified.