Phenotypic and Molecular Detection of Methicillin Resistance in S. aureus

Detecting methicillin resistance is complicated due to the heterogeneity of its phenotypic expression, making its detection difficult in the laboratory; this has led to the development of several techniques to increase its expression in vitro. Four techniques for detecting methicillin resistance wer...

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Bibliographic Details
Main Authors: Maribel Castellano González (Author), Armindo Perozo Mena (Author), Rosana Vivas Vega (Author)
Format: Book
Published: Universidad del Zulia,Facultad de Medicina,Departamento de Enfermedades Infecciosas y Tropicales, 2008-06-01T00:00:00Z.
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Summary:Detecting methicillin resistance is complicated due to the heterogeneity of its phenotypic expression, making its detection difficult in the laboratory; this has led to the development of several techniques to increase its expression in vitro. Four techniques for detecting methicillin resistance were evaluated: the disk diffusion method with oxacillin (OX, 1 μg) and cephoxitin (FOX, 30 μg); the screening test, minimum inhibitory concentration (MIC) and detection of PBP2a, using the presence of mecA gen as a reference method; 286 strains of S. aureus, were processed. The sensibility (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV) and efficiency (EFC) of each method were determined. A total of 50 oxacillin resistant, PBP2a positive (mecA positive) strains were obtained. Sensibility of the OX disk was 99.14%; and of the FOX disk was 100%. The SEN, PPV, NVP and EFC of the other methods were 100%. All the tests, except the OX disk diffusion method (99.14% of ESP), were 100% specific.
Item Description:0075-5222
2477-9628