Direct mecA detection from blood culture bottles by branched-DNA signal amplification

A branched-DNA (bDNA) signal amplification method was used to detect the me cA gene directly from blood culture broth growing staphylococci. BACTEC blo od culture bottles with positive growth indices and containing staphylococc us-like organisms as shown by Gram stain mere tested for the presence of th e mecA gene. Comparison of test results was done among 225 patients tone bl ood culture from each patient). Compared with PCR, the sensitivity and spec ificity of the bDNA method are 100 and 99%, respectively. The bDNA test is carried out in a 96-well format and requires approximately 6 h to perform. Our preliminary results suggest that direct detection of the mecA gene by b DNA signal amplification is (i) sensitive enough to detect mecA directly fr om blood culture bottles without the requirement for subculture and (ii) as sensitive and specific as the PCR-based method.