Abstract

GARZA-RAMOS, Ulises; MARTINEZ-ROMERO, Esperanza  and  SILVA-SANCHEZ, Jesús. SHV-type extended-spectrum b-lactamase (ESBL) are encoded in related plasmids from enterobacteria clinical isolates from Mexico. Salud pública Méx [online]. 2007, vol.49, n.6, pp.415-421. ISSN 0036-3634.

OBJECTIVE: In this work we report the molecular characterization of b-lactam antibiotics resistance conferred by genes contained in plasmids from enterobacteria producing extended-spectrum b-lactamases (ESBL). MATERIAL AND METHODS: Fourteen enterobacterial clinical isolates selected from a group of strains obtained from seven different hospitals in Mexico during 1990-1992 and 1996-1998 were analyzed at the Bacterial Resistance Laboratory (National Institute Public Health, Cuernavaca). Molecular characterization included PFGE, IEF of b-lactamases, bacterial conjugation, PCR amplification and DNA sequencing, plasmid extraction and restriction. RESULTS: Isolates were genetically unrelated. ESBL identified were SHV-2 (5/14) and SHV-5 (9/14) type. Cephalosporin-resistance was transferable in 9 of 14 (64%) clinical isolates with only one conjugative plasmid, DNA finger printing showed a similar band pattern in plasmids. CONCLUSIONS: The dissemination of cephalosporin resistance was due to related plasmids carrying the ESBL genes.

Keywords : enterobacteria; plasmid; ESBL; SHV-5; SHV-2; Mexico.

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