Molecular identification of ESBL-encoding resistance genes, detected in Enterobacteriaceae clinical strains related to hospital infections

Abstract

Extended-spectrum beta-lactamases (ESBL) are recognized worldwide as a public health problem, especially in hospital environment, once they confer resistance to most of the cephalosporins and aztreonam. Currently, there are more than 300 enzymes described, and their wide spectrum eliminates important options of antimicrobial therapy for infections. They are encoded by genes named bla, and the main groups of ESBL are TEM, SHV and CTX-M, although other less frequent groups have already emerged in Latin America and Brazil. Justification. ESBL enzymes and their encoding genes have a wide distribution and are easily transferred among bacterial strains by mobile elements. After the identification of novel-in-Brazil bla genes in one of the strains pertaining to a previous study of our group, it was noticed the importance of identifying the genes detected in the other strains of that study. Objective. To identify, by genetic sequencing, genes bla previously detected in clinical ESBL-producing strains from groups TEM, SHV, CTX-M, GES, VEB e PER-2. Material and Methods. 130 ESBL-producing Enterobacteriaceae strains will be studied. Total DNA will be extracted by heat-chock, and submitted to specific PCR for ESBL groups. Amplified fragments will be purified and sequenced. Nucleotide sequences will be aligned and analyzed in Bioedit software, and the results will be matched in BLAST database of GeneBank. Expected Results. We intend, with the proposed study, to determine the classification of the resistance genes obtained in PCR screening, and so discuss the Public Health importance of the presence of these genes in clinical samples and their possible origin. (AU)