Caracterização do cassete cromossômico mec (SCCmec) e análise fenótípica e molecular de resistência a oxacilina em estafilococos coagulase-negativa e Staphylococcus aureus
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Data
2012-02-24
Autores
Martins, André [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os estafilococos coagulase negativa são patógenos associados a infecções nosocomiais, principalmente bacteremia e sepse. A oxacilina é uma das alternativas de escolha no tratamento das infecções causadas por Staphylococcus spp., contudo, a resistência a esta droga têm se tornado um grande problema nas últimas décadas. O objetivo deste estudo foi caracterizar a sensibilidade à oxacilina em amostras de ECN isoladas de pacientes do Hospital das Clínicas (HC) da Faculdade de Medicina de Botucatu (FMB) por diferentes métodos, determinar a concentração inibitória mínima a antimicrobianos, a triagem de amostras com sensibilidade intermediária à vancomicina e a caracterização do perfil clonal de amostras de MRCoNS isoladas de hemoculturas. Um total de 160 amostras foram analisadas quanto a resistência à oxacilina por meio da técnica de difusão da droga em ágar com disco de oxacilina e cefoxitina, teste de triagem em Ágar Mueller-Hinton com 4 μg/mL de oxacilina e 4% de NaCl, E-test, detecção do gene mecA, e determinação da sensibilidade intermediária a vancomicina em ágar BHI com 4 μg/mL e com 6 μg/mL de vancomicina, além da caracterização do perfil epidemiológico pela tipagem do cassete cromossômico mec (SCCmec) e análise clonal por PFGE de 59 amostras de S. epidermidis e 07 amostras de S. haemolyticus isoladas no período de 2002 a 2009. Um total de 74,4% das amostras foram positivas para o gene mecA. A sensibilidade do método de difusão com disco de oxacilina e da técnica de E-test foi de 99,1% e com especificidade de 90,1%. O disco de cefoxitina apresentou 100% de sensibilidade e a mesma especificidade descrita para o disco de oxacilina. O método de triagem apresentou 94,2% de sensibilidade e a melhor taxa de especificidade com 93,2%. Houve diferença entre as amostras MRCoNS...
Oxacillin is one of the alternatives of choice in the treatment of infections caused by Staphylococcus spp. However, resistance to this drug has become a major problem in recent decades. The aim of this study was to characterize the sensitivity to oxacillin in CNS samples isolated from patients at the School of Medicine University Hospital (HCFMB) - UNESP by different methods, to determine antimicrobial minimum inhibitory concentration, the screening of samples with intermediate sensitivity to vancomycin and characterization of the clonal profile of MRCoNS samples isolated from blood cultures. A total of 160 samples were analyzed for resistance to oxacillin by the drug diffusion technique in agar with oxacillin and cefoxitin, a screening test on Mueller-Hinton agar with 4 μg/mL of oxacillin and 4% NaCl, E-test, mecA gene detection, and determination of intermediate susceptibility to vancomycin in BHI agar with 4 μg/mL and 6 μg/mL of vancomycin, and characterizing the epidemiological profile by typing the cassette chromosome mec (SCCmec) and clonal analysis by PFGE a total of 59 samples of S. epidermidis and 07 samples of S. haemolyticus isolated in the period 2002 to 2009. A total of 74.4% of the samples were positive for mecA. The sensitivity of the oxacillin disk diffusion and E-test technique was 99.1% and specificity 90.1%. The cefoxitin disk showed 100% sensitivity and specificity reported for the same oxacillin disc. The screening method showed 94.2% sensitivity and specificity with the best rate of 93.2%. There were differences between samples when analyzed MSCoNS MRCoNS and the minimum inhibitory concentration (MIC), with higher levels of MIC in the group MRCoNS, and higher rates of multidrug resistance. None of the samples showed resistance or heteroresistant to vancomycin, however, 10 samples grown... (Complete abstract click electronic access below)
Oxacillin is one of the alternatives of choice in the treatment of infections caused by Staphylococcus spp. However, resistance to this drug has become a major problem in recent decades. The aim of this study was to characterize the sensitivity to oxacillin in CNS samples isolated from patients at the School of Medicine University Hospital (HCFMB) - UNESP by different methods, to determine antimicrobial minimum inhibitory concentration, the screening of samples with intermediate sensitivity to vancomycin and characterization of the clonal profile of MRCoNS samples isolated from blood cultures. A total of 160 samples were analyzed for resistance to oxacillin by the drug diffusion technique in agar with oxacillin and cefoxitin, a screening test on Mueller-Hinton agar with 4 μg/mL of oxacillin and 4% NaCl, E-test, mecA gene detection, and determination of intermediate susceptibility to vancomycin in BHI agar with 4 μg/mL and 6 μg/mL of vancomycin, and characterizing the epidemiological profile by typing the cassette chromosome mec (SCCmec) and clonal analysis by PFGE a total of 59 samples of S. epidermidis and 07 samples of S. haemolyticus isolated in the period 2002 to 2009. A total of 74.4% of the samples were positive for mecA. The sensitivity of the oxacillin disk diffusion and E-test technique was 99.1% and specificity 90.1%. The cefoxitin disk showed 100% sensitivity and specificity reported for the same oxacillin disc. The screening method showed 94.2% sensitivity and specificity with the best rate of 93.2%. There were differences between samples when analyzed MSCoNS MRCoNS and the minimum inhibitory concentration (MIC), with higher levels of MIC in the group MRCoNS, and higher rates of multidrug resistance. None of the samples showed resistance or heteroresistant to vancomycin, however, 10 samples grown... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Estafilococos, Staphylococcus aureus, Antibioticos, Medicina tropical, Epidemiologia - Pesquisa, Antibiotics
Como citar
MARTINS, André. Caracterização do cassete cromossômico mec (SCCmec) e análise fenótípica e molecular de resistência a oxacilina em estafilococos coagulase-negativa e Staphylococcus aureus. 2012. 136 f. Tese (doutorado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Medicina de Botucatu, 2012.