Detecção dos genes bla em bactérias produtoras de ESBL isoladas de pacientes com doenças hematológicas

Abstract

The production of extended-spectrum beta-lactamases (ESBLs) among clinical isolates of Gram-negative bacteria is an important mechanism of resistance to -lactam antibiotics. It is the major cause of treatment failure using cephalosporins, thereby causing limitations in therapeutic choice and are enzymes mediated by plasmids that have the hability to hidrolisy oximino-cephalosporins and aztreonam. This study aimed to identify key genes responsible for production of ESBLs in Gram-negative Enterobacteriaceae and Pseudomonadaceae family. There were 12 Gram-negative bacteria that were positive for ESBL isolated from patients with hematologic malignancies treated at HEMOAM Foundation from July 2007 to August 2008. The detection and identification of genes blaTEM, blaSHV, blaCTX-M and blaOXA were performed by PCR and nucleotide sequencing. E. coli bacteria were more frequent among ESBL isolates. All isolates were susceptible to imipenem and were resistant to chloramphenicol and tetracycline. The bacteria carried genes for TEM, SHV, CTX-M and OXA on both chromosomes and in plasmids. The presence of multigene (blaTEM, blaSHV, blaCTX-M and blaOXA) and the non-antibiotic resistance detected in the -lactam and non-enterobacteria Enterobacteriaceae isolated from clinical specimens in this research is relevant because it provides information about the presence of this threat antibiotic resistance in our region.