ROUTINE USE OF PCR REVERSE CROSS-BLOT HYBRIDIZATION ASSAY FOR RAPID IDENTIFICATION OF MYCOBACTERIUM SPECIES GROWING IN LIQUID-MEDIA

A PCR-reverse cross-blot hybridization assay procedure that is able to rapidly identify 13 species of clinically relevant mycobacteria was e valuated for routine use in the identification of acid-fast isolates g rowing in BACTEC 460 TB (12B and 13A) and BACTEC 9000 MB (Myco/F) liqu id media. Eight of the probes used were already described by Kox et al . (L. F. F. Kox et al., J. Clin. Microbiol. 33:3225-3233, 1995). In ad dition, we used six other probes specific for ill. chelonae, M. malmoe nse or M. szulgai, M. genavense, M. goronae, M. terrae, and Ill. marin um/M. ulcerans that we designed ourselves. This procedure allowed us t o identify 459 mycobacterial species directly from broth cultures of 5 ,466 clinical samples collected over 1 year and processed ,vith the ra diometric or nonradiometric BACTEC system. Our results were in agreeme nt with those obtained by conventional identification methods and also with those obtained by mycolic acid analysis by high-performance liqu id chromatography. This assay seems to be a reliable procedure for the routine identification of mycobacteria, providing an accurate identif ication of mycobacterial isolates more rapidly than conventional tests , with remarkable implications for an efficacious specific antimycobac terial therapy.