Detecção do operon ica da produção de biofilme, gene mecA de resistência à oxacilina e identificação de espécies de Staphylococcus spp. diretamente dos frascos de hemoculturas pela técnica de PCR multiplex

• Autor(a) principal: Rocchetti, Taisa Trevizani [UNESP]
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/110456
• topic: Biofilme; Microorganismos - Efeito dos antibioticos; Estafilococos; Reação em cadeia de polimerase; Identificação; Microorganismos - Effect of antibiotics on; Biofilms

A clear shift in the etiology of sepse has occurred in the last decade. Recent data from the National Healthcare Safety Network (NHSN) show that Gram-positive cocci have exceeded Gram-negative bacilli as the major etiological agents. In this respect, coagulase-negative staphylococci (CoNS) have become the most frequent. However, most clinical laboratories do not identify these microorganisms to species level due to the need for a series of biochemical tests. The application of molecular biology techniques, including the polymerase chain reaction (PCR), for bacterial identification proved to be promising due to their speed, accuracy and sensitivity. The aim of this study was to evaluate the efficiency, accuracy and sensitivity of multiplex PCR for the detection of Staphylococcus spp. frequently found in blood cultures, investigation of the ica operon involved in biofilm formation and the mecA gene encoding oxacillin resistance, and direct detection of major CoNS species in blood culture flasks. A total of 371 blood culture samples positive for Staphylococcus spp. obtained from patients seen at the Hospital of the Botucatu School of Medicine (FMB) were analyzed. The strains were isolated and identified by conventional biochemical tests. Simultaneously, bacterial DNA was extracted directly from the blood cultures for multiplex PCR. S. aureus was isolated from 85 (23%) of the 371 samples studied and CoNS from 286 (77%). Among the latter, 152 (53.1%) isolates were identified as S. epidermidis, 36 (12.6%) as S. haemolyticus, 36 (12.6%) as S. hominis, 23 (8%) as S. capitis, 18 (6.3%) as S. warneri, 7 as S. caprae, 5 as S. simulans, two as S. lugdunensis, two as S. cohnii, one as S. saprophyticus, one as S. schleiferi, and one as S. xylosus. S. haemolyticus and S. hominis were concomitantly identified in one sample and S. haemolyticus and S. epidermidis in another. Forty-three (50.6%) of the 85 S. aureus strains were resistant to oxacillin in ...