Prevalência e tipagem molecular de Staphylococcus aureus isolados de uma Unidade de Terapia Intensiva de um hospital escola do município de Goiânia, Goiás

• Autor(a) principal: Veloso, Jéssica De Oliveira
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/0013000006z47
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/6697
• topic: MRSA; iMLSb; PVL; VISA; Fatores de virulência; SCCmec; PFGE; Virulence factors; CIENCIAS BIOLOGICAS::MICROBIOLOGIA

Staphylococcus aureus is an important pathogen related to nosocomial infections, with high prevalence, morbidity and mortality rates. In this context, the Intensive Care Units (ICU) has been high-risk areas for the selection of multiresistant strains. The environment (objects, equipment and surfaces) of an ICU can also get contaminated, and microorganisms may remain viable for a long period of time, and can colonize patients, employees, visitors and other environments. The objectives of the study were to determine the prevalence of S. aureus contamination in patients and ICU environment of a university hospital in the city of Goiânia-GO, as well as to determine the antimicrobial susceptibility and virulence profile of the isolates and perform molecular typing of methicillin-resistant S. aureus (MRSA) isolates. The isolation and presumptive identification of S. aureus by phenotypic techniques and the confirmation of the species by detection of femA gene by PCR were performed. The isolates were subjected to diskdiffusion test for determining antimicrobial susceptibility profile, and those showing resistance to cefoxitin were subjected to E-Test® to determine the minimum inhibitory concentration (MIC) to oxacillin and vancomycin, as well as the mecA gene detection for identification of MRSA strains. In these isolates the SCCmec typing was performed. In all S. aureus isolates were detected virulence factors-coding genes and held the genetic comparison for determining the similarity profile by pulsed field gel electrophoresis. Fifty hundred and thirty six swabs were collected being 134 of patients and 402 of ICU environment. The prevalence of colonization by S. aureus was 12.7% (68/536), being 13.4% (18/134) for patients and 12.4% (50/402) for the environment. The highest resistance rate presented was to penicillin (85.3%) followed by erythromycin (69.1%) clindamycin (66.2%) and sulfamethoxazole-trimethoprim (54.4%). Fifty-six isolates (82.4%) were classified as multiresistant. The prevalence of MRSA was 20.6% (14/68), and seven isolates (10.3%) presented intermediate susceptibility to vancomycin (VISA). The inducible resistance phenotype (iMLSb) was found in 11 strains (16.2%) and the constitutive resistance (cMLSb) in 25 (36.8%). Eleven isolates showed genes encoding for at least one virulence factor and were detected six virulence profiles. Of the 14 MRSA strains, six (42.9%) were SCCmec type IV, five (35.7%) SCCmec type I, two (14.3%) SCCmec type II and one (7.1%) SCCmec type III. PFGE analysis showed genetic diversity among the isolates, although a cluster grouped 16 isolates showing the spread of the bacteria among patients and environment. One MRSA isolate showed genetic relationship to the USA300 strain and two isolates MRSA/VISA were similar and another identical to the clone USA400. The results suggest that the prevalence of S. aureus and MRSA remains high in health institutions, especially in the ICU, with high rates of antimicrobial resistance and pathogenic potential. The detection of these microorganisms in the environment shows risk of cross-transmission primarily via health professionals. Identification of isolates with genetic background of strains acquired in the community alert to a flow of intra and inter- hospital and community environment. In addition, it is believed that environmental surfaces can be acting as reservoirs of genes of resistance and virulence as well as potential sources of contamination to patients, professionals and environments.