EFFICACY OF THE “GEN-PROBE MYCOBACTERIUM TUBERCULOSIS DIRECT TEST (MTD) ” FOR DETECTION OF MYCOBACTERIUM TUBERCULOSIS IN CLINICAL SPECIMENS Comparison between the MTD and the Test by Culture on Ogawa's Egg Medium or in the MB Check System

• Published in: Kekkaku Vol. 69; no. 1; pp. 7 - 14
• Main Authors: AOYAGI, Teruo, TOYODA, Takeo, OSUMI, Mitsuhiko, KITAHARA, Kazushi, KONNO, Shinkichi, YOSHIMURA, Tadashi, MIYAGI, Chieko, GOTO, Susumu
• Format: Journal Article
• Language: English; Japanese
• Published: Japan JAPANESE SOCIETY FOR TUBERCULOSIS 1994
• Subjects: Adult; Aged; Bacteriological Techniques; Culture Media; DNA Probes; Female; Humans; Male; MB Check; Middle Aged; Molecular Probe Techniques; MTD; Mycobacterium tuberculosis - isolation & purification; RNA, Bacterial; RNA, Ribosomal; rRNA; Tuberculosis - diagnosis
• DOI: 10.11400/kekkaku1923.69.7
• ISSN: 0022-9776

Three or more weeks are usually required for detecting Mycobacterium tuberculosis by the known culture methods, and therefore, the development of a rapid bacteriological diagnostic method for M. tuberculosis has been urgently awaited. Recently, Gen-Probe Inc. has developed the “Gen-Probe Mycobacterium Tuberculosis Direct Test (MTD) ”, which is based on amplification of the ribosomal RNA (rRNA) of M. tuberculosis in clinical specimens and hybridization of the amplified rRNA with a M. tuberculosis-specific DNA probe, as a rapid direct diagnostic method for tuberculosis. We therefore compared the sensitivity and specificity of the MTD in detecting M.tuberculosis with the culture methods on Ogawa's egg medium and in the MB Check System, using 107 clinical specimens as test material. The results obtained are as follows: 1. Of the 61 clinical specimens which were negative when cultured on Ogawa's egg medium, 13 (21.3 %) were positive for M. tuberculosis using the MTD, and of the 48 clinical specimens which were negative when cultured in the MB Check System, 8 specimens (16.7 %) were positive for M. tuberculosis using the MTD. 2. All of the specimens which yielded growth of M. tuberculosis (identified by the DNA probe) either on Ogawa's egg medium or in the MB Check System, except one, were positive for M. tuberculosis in the MTD. The only one exception was a specimen which was positive for M. tuberculosis in both Ogawa's medium and the MB Check System. 3. Of the 28 specimens which yielded growth of atypical mycobacteria (identified by the DNA probe) in cultures, 27 specimens were negative for M. tuberculosis in the MTD. 4. The specimens which were negative both on Ogawa's egg media and in the MB Check System but positive for M. tuberculosis in the MTD must have contained few tubercle bacilli, because the clinical status of the 6 patients from whom these specimens were taken suggested that their tuberculosis was still active. Based on these results, we concluded that the MTD is a very efficient method of direct detection of M. tuberculosis in clinical specimens and for the rapid diagnosis of tuberculosis.