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The Journal of the Japanese Society for Clinical Microbiology |
Biblioraphy Information
| ArticleTitle |
Evaluation of Microdilution Susceptibility Test for Nontuberculous Mycobacteria Using the ATP Method |
| Language |
J |
| AuthorList |
Masayuki Horikawa1), Isao Nishi1), Masahiro Toyokawa1), Naoki Sato2), Yutaka Okazawa2), Seishi Asari1) |
| Affiliation |
1) Clinical Laboratory, Osaka University Hospital
2) Kyokuto Pharmaceutical Industrial CO., LTD. |
| Publication |
J.J.C.M.: 14 (3), 164-176, 2004 |
| Received |
April 8, 2004 |
| Accepted |
September 7, 2004 |
| Abstract |
We have developed a broth microdilution susceptibility test method for nontuberculous mycobacteria (NTM); in this test method, adenosine triphosphate (ATP) is measured through bioluminescence, with viable count as the indicator. We have conducted the basic analysis of the method and compared the method with the broth microdilution method (MB method) using four ATCC referece strains and 45 clinical isolates. As a result of the examination of the ATP-measuring method (ATP method), it has been shown that 30-minute pre-processing at room temperature and extraction at 60° C for 10 minutes were appropriate steps. For the ATP method, judgment was made by measuring the relative light unit (RLU) ratio after culturing the microplate for 5 days, and comparison was made with the MIC value after culturing for 7 days. When the positive values for growth were set to an RLU ratio of ≥ 0.1 for 7 drugs, that is, streptomycin, ethambutol, kanamycin, isoniazid, levofloxacin, ethionamide and amikacin, and to an RLU ratio of ≥ 0.03 for rifampicin and clarithromycin, the rate of concordance with the MB method was rather lower (84.4%) for Mycobacterium kansasii ATCC 12478, whereas 97.8-100% concordance rates were obtained for 3 ATCC reference strains. Regarding clinical isolates, the concordance rates obtained for Mycobacterium intracellulare, Mycobacterium avium, and M. kansasii were 92.2%, 97.2% and 100%, respectively. From the above results, we have concluded that the ATP method is useful as a method of testing drug susceptibility of NTM. |
| Keywords |
nontuberculous mycobacteria (NTM), adenosine triphosphate (ATP), minimum inhibitory concentration (MIC), bioluminescence |
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