Abstract
Among 177 extended-spectrum beta-lactamase-producing Klebsiella pneumoniae isolates collected from 11 Slovenian hospitals in 2005 and 2006, 60 (34%), from eight hospitals, harbored genes for CTX-M enzymes, with bla(CTX-M-15) detected by sequencing. These 60 isolates comprised 11 pulsed-field gel electrophoresis-defined strains, with several clusters of closely related isolates. Plasmids encoding CTX-M-15 enzyme were highly transmissible.