Use of Gen-Probe AccuProbes to identify Mycobacterium avium complex, Mycobacterium tuberculosis complex, Mycobacterium kansasii, and Mycobacterium gordonae directly from BACTEC TB broth cultures

Abstract

To evaluate the utility of Gen-Probe AccuProbes for the identification of mycobacteria directly from BACTEC TB 12B vials containing acid-fast bacilli, culture results for 11,375 clinical specimens other than blood received from 1 January 1992 to 30 September 1993 were reviewed retrospectively. During this period, a total of 359 of 11,375 BACTEC vials were positive for acid-fast bacilli and were evaluated for mycobacteria with one or more probes: 224 were probed for Mycobacterium tuberculosis complex, 253 were probed for Mycobacterium avium complex, 64 were probed for Mycobacterium kansasii, and 77 were probed for Mycobacterium gordonae. After initial testing with the probes, 75 vials were positive for M. tuberculosis complex, 99 were positive for M. avium complex, 11 were positive for M. kansasii, and 55 were positive for M. gordonae. Repeat testing of vials that were initially probe negative or testing of colonies from subcultures of these vials identified an additional 11 M. tuberculosis, 27 M. avium complex, 1 M. kansasii, and 9 M. gordonae that were not detected on initial screening. On the basis of these data, the percentage of organisms identified directly from the BACTEC TB 12B vials upon initial screening with each of the four AccuProbes was 87.2% for M. tuberculosis complex, 78.6% for M. avium complex, 91.7% for M. kansasii, and 85.9% for M. gordonae.