Charakterisierung vermindert Penicillin-empfindlicher Streptococcus-pneumoniae-Isolate des Serotyps 23F in Deutschland

Streptococcus pneumoniae is one of the most important bacteria causing respiratory tract infections, meningitis and otitis. Penicillin is the remedy of first choice for pneumococcal infections, but since several years penicillin- and multiresistant strains have spread worldwide. Because of their capsular polysaccharides pneumococci are divided up into serotypes. One of the most important serotypes to provide penicillin resistance is serotype 23F. In this study 46 penicillin non-susceptible strains of this serotype, isolated by the National Reference Center for Streptococci, were analyzed by multilocus sequence typing (MLST) with regard to their genetic relationship. Three clones are predominating in Germany: the Spain 23F-1-clone (sequence type [ST] 81) and a clone that up to now has only been isolated once in the Netherlands (ST 277) and the Taiwan 23F-15-clone (ST 242). These results indicate that resistant pneumococcal clones come to Germany mainly because of tourism and immigration, but in contrast to many other European countries they do not spread there any further. This could be a consequence of economical use of antibiotics in Germany. In addition eleven new sequence types were isolated, six of which are variants of already known sequence types, five isolates have completely new sequence types. For the xpt-gene we found two alleles which have been unknown till now. MLST can be easily practiced and it is an objective method that produces unambiguous, reproducable, easy portable and comparable results. This method is very suitable for the examination of local and global spreading of antibiotic-resistant pneumococcal strains