Estudo sobre a ocorrência de enterobactérias produtoras de ESBL isoladas de pacientes internados em unidades de pós-operatório de cirurgia cardíaca de um hospital da rede pública do Rio de Janeiro

• Autor(a) principal: Vasques, Márcia Regina Guimarães
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14400
• topic: Enterobacteria; Extended spectrum β-lactamase; Bacterial resistance; Polymerase chain reaction; Amp-C; Enterobactérias.; β-lactamase de espectro estendido; Resistência bacteriana; Reação de Polimerase em Cadeia; AmpC; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA::MICROBIOLOGIA APLICADA

Healthcare-associated infections are a major problem in hospital units as well as in units outside hospital, where procedures are performed. In Brazil, differently from other countries, a large proportion of these infections are caused by extended spectrum beta-lactamase (ESBL) producing Gram-negative microorganisms. These enzymes, which hydrolyse β-lactams, are considered of clinical importance worldwide. Their localization in genes that are located in móbile structures facilitate cross infection. This study was performed with bacterial isolates found in clinical specimens and faeces of patients hospitalized in a public hospital in the city of Rio de Janeiro, Brazil. These patients were in two different cardiological intensive care units from January till December 2007. The goal of the study was the phenotypic and genotypic characterization of the bacterial isolates which were associated with colonization or infection. Phenotypic and genotypic tests were performed in Universidade do Estado do Rio de Janeiro (Rio de Janeiro State University) and included biochemical tests, susceptibility tests, a comfirmatory test for the expression of ESBL, and polymerase chain reaction (PCR) with specific primers for five gentes : blaTEM, blaSHV, CTX-M1, Toho1 and AmpC. The most frequently isolated bactéria were Escherichia coli (25%) and Klebsiella pneumoniae (30,56%), and the most prevalent genes were blaTEM (41,6%), AMPC (41,6%) blaSHV (33,3%), CTX-M1 (25%), and Toho1 (19,44%). In 25% of samples we identified enterobacteria that were not E. coli, K. pneumoniae oor Proteus spp, but with the ESBL phenotype and the expression of the same genes, suggesting these microbes needed investigating. The most sensitive substrate for expressing synergism in the double-disk diffusion test was ceftriaxone (80%). We also identified that 17% of ESBL positive isolates showed co-production of AmpC and 50% showed more than one gene tested by PCR. The presence of carbapenemase was studied in bacterial isolates with intermediate susceptibility to ertapenem, by a modified Hodge test. The findings in the present study characterize the co-production of AmpC and ESBL, and suggest the need for reviewing detection methods used and possibly using other methods for the detection of other resistance patterns in our Institution.