Caracterização fenotípica e molecular de amostras de Enterococcus isoladas em hospitais da cidade do Natal/ RN

• Autor(a) principal: Costa, Mizia Karla de Carvalho Martins
• Data de Publicação: 2014
• 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/1/14415
• topic: Enterococcus; Virulence; Antimicrobial resistance; PFGE; Enterococcus; Fatores de virulência; PFGE; Resistencia aos antimicrobianos; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA::MICROBIOLOGIA APLICADA::MICROBIOLOGIA MEDICA

Enterococcus has emerged worldwide as one of the most important pathogens related to health care. They have ability to acquire resistance genes, including vancomycin, and have several virulence-associated factors, which contribute greatly to their permanence in the host, facilitating its dissemination, particularly in the hospital environment. The aim of this study was to characterize, by phenotypic and genotypic tests, strains of Enterococcus isolated from infections occurred in patients enrolled in four health-care institutions located in the city of Natal, in the period September 2010 to June 2011. Enterococcus species were characterized by conventional physiological tests and polymerase chain reaction (PCR) multiplex, using specific primers for the characterization at genus and species level. The antimicrobial susceptibility profiles were evaluated by agar diffusion testing. MIC values for vancomycin, teicoplanin and linezolid were determined by E-test, and the vancomycin resistance genotype was analyzed by PCR. Virulence (asa1, cylA, esp, gelE and hyl) were detected by multiplex PCR assays. The genetic polymorphism was evaluated by pulsed field gel electrophoresis (PFGE) using the SmaI. 117 samples were obtained from 116 patients. The results revealed that the species E. faecalis was prevalent (91.4%). The susceptibility testing revealed that the highest resistance rates were associated with tetracycline (58.2%) and high-levels of streptomycin (36.7%). The resistance to vancomycin was detected in one isolate of E. faecium carrying the vanA genotype, corresponding to the first detection of this resistance trait in RN State. This sample was isolated from a case of co-infection with E. faecalis susceptible to vancomycin. Additionally, intermediate resistance to linezolid was found in three isolates of E. faecalis. Among the virulence encoding genes, gelE was the prevalent (83.8%). According to the species, the prevalent genotype among E. faecalis isolates was the concomitant presence of esp and gelE (31.6%). While in E. faecium isolates the presence of esp (28.6%) was prevalent. E. gallinarum isolate harbored both asa1 and cylA. The hyl gene was not detected. Analysis of genetic polymorphism of the strains by PFGE showed a high polyclonality. Given the characteristics of resistance and virulence observed in this study and the emergence of vancomycin-resistance, this study calls the attention to the need for screening, particularly among healthy carriers, and establishing policies to control the spread of these strains in health institutions, even in areas where such features are still uncommon.