Complex endemic situation regarding extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a hospital in Slovenia.

The first detailed epidemiological study of extended-spectrum beta-lactamase (ESBL)-producing organisms identified in Slovenia was carried out. It was performed on a group of 40 Klebsiella pneumoniae isolates that were randomly selected from all putative ESBL producers of this species recovered in a large hospital in Celje in 1997-2001. At least three different ESBLs, SHV-2, -5, and -12, were produced by the isolates and these enzymes seem to be common in nosocomial Enterobacteriaceae populations in countries of the region (e.g., Italy, Hungary, Croatia). The analysis revealed a complex epidemiology of the organisms, illustrated mostly by their high clonal variety but also by the diversity of their beta-lactamase and plasmid content, mating capability, and antimicrobial susceptibility. Although some cases of a 'fresh' dissemination of strains or plasmids could be identified, the overall situation should be described rather as endemic, and its complexity may be in part attributed to the late introduction of the ESBL detection procedure to the hospital.