title: Direct antimicrobial drug susceptibility testing of Mycobacterium tuberculosis by the radiometric method.
abstract: Direct-drug-susceptibility tests were performed on clinical specimens positive for acid-fast bacilli by either Ziehl-Neelsen or fluorochrome staining. The results of conventional agar dilution (Vestal, 1975) and a modified radiometric (BACTEC) method were compared. A total of 580 smear-positive specimens were tested by the BACTEC method at three separate sites. Three hundred and seventy-seven of these were culture positive for M. tuberculosis, and 343 (91%) yielded acceptable direct-susceptibility-test results. We used the conventional method to determine that 343 of 519 smear-positive specimens were culture positive for M. tuberculosis, and 212 (62%) produced acceptable results within 3 wks. Conventional results were reported in 3-4 wks, while the time required to obtain results with the BACTEC method ranged from 5 to 21 days (average 11.5 days). Results indicate that the radiometric method provides reportable results more frequently with time savings as compared to the conventional method.
mesh_terms: D001431:Bacteriological Techniques; D004977:Ethambutol / Q000494:pharmacology; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D011874:Radiometry / Q000379:methods; D012293:Rifampin / Q000494:pharmacology; D013183:Sputum / Q000032:analysis; D013307:Streptomycin / Q000494:pharmacology
chemical_list: D004977:Ethambutol; D007538:Isoniazid; D012293:Rifampin; D013307:Streptomycin