Abstract

CASABONNE, Cecilia; PEREZ, Jorgelina; BALAGUE, Claudia  and  FERNANDEZ, Luisa. ß-lactamases diversity in clinical isolates of enterobacterias. Acta bioquím. clín. latinoam. [online]. 2012, vol.46, n.3, pp.405-412. ISSN 0325-2957.

The rapid emergence of antimicrobial resistance due to extended spectrum b-lactamases (ESBL) has a significant impact on public health. ESBL, produced by gram-negative bacilli, are enzymes that confer resistance to penicillins, cephalosporins and aztreonam, but not to carbapenems or cephamycins, and are usually inhibited by clavulanic acid. The aim of this study was to evaluate b-lactam resistance within isolates of Klebsiella pneumoniae, Escherichia coli, and Proteus mirabilis and to characterize the b-lactamases responsible for this resistance. A total of 2,030 strains (362 Klebsiella pneumoniae, 1,250 Escherichia coli, and 175 Proteus mirabilis) isolated from patients at Hospital Provincial del Centenario in Rosario-Santa Fe were analyzed from 2008 to 2009. Antibiotic sensitivity tests were performed according to Clinical and Laboratory Standard Institute recommendations. Molecular detection of ESBL-related bla genes, including bla_TEM, bla_SHV, bla_CTX-M and bla_PER was performed by polymerase chain reaction (PCR) using specific primers. The strains were phenotipically confirmed as ESBL producers and the isolates carried several bla genes. Three different b-lactamases were detected: SHV-related, TEM-related and CTX-M-related, showing that two or more genes may coexist in the same bacterium.

Keywords : Extended spectrum ß-lactamases; Enterobacteriaceae; Polymerase chain reaction.

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