Outbreak of ceftazidime-resistant Klebsiella pneumoniae in a pediatric hospital in Warsaw, Poland: Clonal spread of the TEM-47 extended-spectrum beta-lactamase (ESBL)-producing strain and transfer of a plasmid carrying the SHV5-like ESBL-encoding gene

In 1996 a large, 300-bed pediatric hospital in Warsaw, Poland, started a pr ogram of monitoring infections caused by extended-spectrum beta-lactamase ( ESBL)-producing microorganisms. Over the first 3-month period eight Klebsie lla pneumoniae isolates were identified as being resistant to ceftazidime. Six of these were found to produce the TEM-47 ESBL, which we first describe d in a K. pneumoniae strain recovered a year before in a pediatric hospital in Lodz, Poland, which is 140 km from Warsaw. Typing results revealed a ve ry close relatedness among all these isolates, which suggested that the clo nal outbreak in Warsaw,vas caused by a strain possibly imported from Mdi. T he remaining two isolates expressed the SHV-5-like ESBL, which resulted fro m the horizontal transfer of a plasmid carrying the bla(SHV) gene between n onrelated strains. The data presented here exemplify the complexity of the epidemiological situation concerning ESBL producers typical for large Polis h hospitals, in which no ESBL-monitoring programs were in place prior to 19 95.