Rapid identification of mycobacteria from culture using acridinium-ester-labelled DNA probes.

Objectives: Our study used newly developed acridinium-ester-labelled DNA (AE-DNA) probes on 183 mycobacterial isolates, performing the tests on 12B Bactec vials and Loewenstein-Jensen (LJ) slants.

Methods: The probe results were verified using the conventional method as a reference.

Results: The probe for M. tuberculosis complex correctly identified 131 of 133 M. tuberculosis isolates, with two false negatives and no false positives, for a sensitivity of 98.5% and a specificity of 100%. The M. gordonae probe correctly identified 27 out of 27 M. gordonae isolates, with no false negatives and one false positive, for a sensitivity of 100% and a specificity of 90.9%. One hundred sixty-eight of the 183 isolates were screened in accordance with an algorithm, designed primarily for the rapid detection and identification of M. tuberculosis.

Conclusion: The use of the algorithm considerably reduced detection time: M. tuberculosis strains were identified within 16.2 +/- 2.3 days, while identification by conventional method required 35.7 +/- 5.5 days. Probe testing resulted in a cost increase of 67.8%.