Emergence of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae during the years 2000 and 2004 in Helsinki, Finland.

The molecular epidemiology of 33 Escherichia coli and 81 Klebsiella pneumoniae extended-spectrum beta-lactamase-producing healthcare-associated and community-acquired isolates collected in the Helsinki district during 2000-2004 was investigated. Clonality studies, antimicrobial susceptibility and genotyping of the isolates were performed. Newly emerging CTX-M-producing E. coli and bla(SHV-12)-producing K. pneumoniae isolates were detected. Clonal clusters of both species persisted throughout the study period.