Molecular epidemiology of extended-spectrum beta-lactamases from Klebsiella pneumoniae strain isolated in Zagreb, Croatia

In order to assess the molecular epidemiology of 40 previously identified e xtended-spectrum beta -lactamase (ESBL)-producing clinical isolates of Kleb siella pneumoniae, gene sequencing was performed. While the previous examin ation of these isolates revealed one TEM producer, the sequencing procedure performed in this study identified 13 additional TEM producers, and all of the sequenced genes reflected production of nonESBL TEM-1. All 38 suspecte d SHV producers were confirmed to be carriers of bla(SHV-ESBL) genes using the PCR/NheI test and sequencing. Among them, types SHV-2, SHV-5, and SHV-1 2 were found in 20, 10, and 7 isolates, respectively, and SHV-2a was identi fied in 1. SHV-5 and SHV-12 conferred higher resistance to ceftazidime and cefepime, while SHV-2 and SHV-2a raised the minimum inhibitory concentratio ns of cefotaxime and cefpirome. Fourth-gene ration cephalosporins were foun d to be more active against the isolates than third-gene ration cephalospor ins.