Multidrug-resistant Streptococcus pneumoniae in Poland: Identification of emerging clones

Penicillin resistance among Streptococcus pneumoniae isolates has rapidly e merged in Poland during the last decade and has reached prevalence levels o f up to 14.4% in 1997. In order to investigate the nature of this increase, a molecular epidemiological analysis of non-penicillin-susceptible multidr ug-resistant pneumococci isolated in 1995 and 1996 was conducted. Thirty-se ven patients who suffered mainly from upper respiratory tract infections an d pneumococcal pneumonia were enrolled in this study. The medical centers t o which the patients were admitted were located in 16 Polish towns across t he country. Eight distinct BOX PCR types were observed, representing 14 sub types. Restriction fragment end labeling (RFEL) analysis divided the pneumo coccal strains into 16 distinct types. By combining the BOX PCR and RFEL da ta, four genetically distinct clusters of strains were identified. Two clus ters represented the genetic clones 23F and 9V,which have recently emerged all over the world. The two other genetic clusters, which represented serot ypes 23F and 6B, clearly predominated in the analyzed collection of Polish non-penicillin-susceptible pneumococcal strains. Since the latter clusters did not match any of the 133 RFEL types of non-penicillin-susceptible pneum ococci collected in 15 other countries, their Polish clonal origin is most likely.