Detection of methicillin resistance in Staphylococcus aureus isolated from pediatric patients: Is the cefoxitin disk diffusion test accurate enough?

We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar...

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Detalles Bibliográficos
Autores: Mimica, M. J., Berezin, Eitan Naaman [UNIFESP], Carvalho, R. L. B., Mimica, I. M., Mimica, L. M. J., Safadi, Marco Aurelio Palazzi [UNIFESP], Schneider, E., Caiaffa-Filho, H. H.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2007
País:Brasil
Institución:Universidade Federal de São Paulo (UNIFESP)
Repositorio:Repositório Institucional da UNIFESP
Idioma:inglés
OAI Identifier:oai:repositorio.unifesp.br:11600/42880
Acceso en línea:http://dx.doi.org/10.1590/S1413-86702007000400009
http://repositorio.unifesp.br/handle/11600/42880
Access Level:acceso abierto
Palabra clave:MRSA
disc diffusion
cefoxitin
mecA
Descripción
Sumario:We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar screening plates were 100% sensitive and specific for mecA presence. Oxacillin and cefoxitin disks gave sensitivities of 96 and 92%, respectively, and 98% specificity. Alterations of CLSI cefoxitin breakpoints increased sensitivity to 98%, without decreasing specificity. Our results highlight the importance of a continuing evaluation of the recommended microbiological methods by different laboratories and in different settings. If necessary, laboratories should use a second test before reporting a strain as susceptible, especially when testing strains isolated from invasive or serious infections. With the new (2007) CLSI breakpoints, the cefoxitin-disk test appears to be a good option for the detection of methicillin resistance in S. aureus.