Distribution of extended-spectrum β-lactamase types in a Brazilian tertiary hospital

Abstract

Introduction: Epidemiological data on the prevalence of extended-spectrum β-lactamases (ESBLs) are scarce in Brazil despite the fact that these data are essential for empirical treatment and control measures. The objective of this study was to evaluate the prevalence of different ESBLs by type and distribution in a tertiary hospital in southern Brazil. Methods: We evaluated 1,827 enterobacterial isolates between August 2003 and March 2008 isolated from patients at a tertiary hospital. Samples were identifi ed using a Vitek automated system and were confi rmed by biochemical testing. The identify ed ESBL strains were characterized by phenotypic methods, polymerase chain reaction (PCR), and sequencing. Genetic similarities were evaluated by pulsed-fi eld gel electrophoresis. Results: It was 390 (21.3%) ESBL-producing strains, which expressed the ESBLs CTX-M (292), SHV (84), CTX and SHV (10), TEM (2), and PER (2). Conclusions: The prevalence of ESBL-expressing strains was high, especially in Klebsiella pneumoniae and Enterobacter spp. CTX-M was the predominant type of ESBL observed, and its genetic variability indicates a polyclonal distribution.