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

Brazilian Journal of Infectious Diseases

M.J. Mimica¹  E.N. Berezin¹  M.A.P. Sáfadi¹  R.L.B. Carvalho²  I.M. Mimica²  E. Schneider²  L.M.J. Mimica²  H.H. Caiaffa-Filho² 

[1] Department of Pediatrics;Santa Casa University Hospital;

关键词: MRSA;    disc diffusion;    cefoxitin;    mecA;   

DOI  :  10.1590/S1413-86702007000400009

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown