Detection of methicillin-resistant Staphylococcus by resistance phenotype and amplification of mecA gene / 中华检验医学杂志

ABSTRACT

Objective To study the detection characteristics of methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococcus.Methods Disks with 1 ?g of oxacillin and 30 ?g of cefoxitin were used to detect the inhibition zone of staphylococcus aureus and coagulase-negative staphylococcus at both 35℃ and 30℃ according to the method and breakpoint recommended by CLSI.The agar surface of oxacillin plate with sodium chloride was spotted.mecA gene was amplified by PCR.Results For detection of MRSA, disks of oxacillin and cefoxitin at 30℃ have the same sensitivity of 100%, however, the sensitivity of cefoxitin( 94.7%) is a little higher than that of oxacillin (93.3%) at 35℃. For detection of MRCNS, the sensitivity of 100% can be obtained by disks of both oxacillin and cefoxitin at both 30℃ and 35℃.The sensitivity and specificity of oxacillin plate with sodium chloride are the same as those of disks of oxacillin and cefoxitin at 30℃ for detection of MRSA, its sensitivity is lower than that of disks for detection of MRCNS.Conclusion The detection of methicillin-resistant Staphylococcus can be improved by the use of cefoxitin disk.