The colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was standardized for direct detection of rifampin-resistant Mycobacterium tuberculosis in sputum samples. The sensitivity and specificity of the direct MTT assay matched those of the standard indirect susceptibility assay on 7H10 medium, and interpretable results were obtained for 98.5% of the samples wit...

1. Staining and culture. Current methods of specimen staining and culture used for M. tuberculosis are acceptable for most NTM species. The preferred methodology includes fluorochrome staining and culture in a liquid medium as well as on Middlebrook 7H10 or 7H11 agar. Species for which special growth conditions are needed include those responsible for cutaneous disease, which need lower incubat...

The objectives of this study were to investigate the origin of highly discordant rifampin (rifampicin) (RMP) drug susceptibility test results obtained for Mycobacterium tuberculosis strains during proficiency testing. Nine Supra-National Tuberculosis Reference Laboratories tested the RMP susceptibilities of 19 selected M. tuberculosis strains, using standard culture-based methods. The strains w...

INTRODUCTION Many studies have shown epidemiological links between strains isolated in tap water, and those isolated from patients. Molecular methods linked to PCR are more reliable and faster for identification of non- tuberculous mycobacteria (NTM). In this study molecular methods were used for identification and typing of NTM. MATERIALS AND METHODS Five hundred ml of 85 water samples was p...

A new agar medium to perform pyrazinamide (PZA) susceptibility testing with Mycobacterium tuberculosis has been developed. This medium has an acidic pH of 6.0 instead of the usual for agar media, pH 6.8, to provide optimal conditions for PZA activity, and it also differs from conventional Middlebrook 7H10/7H11 agar in that animal serum (fetal or calf bovine or fetal equine serum) is used instea...

An efficient protocol for the manual fluorescent MGIT culture system combined with rapid confirmation of Mycobacterium avium subsp. paratuberculosis (MAP) growth in the broth culture was established and evaluated for the detection of viable MAP in direct quantitative PCR (QPCR) positive bovine feces. Manually detected fluorescence emissions from MGIT tubes were analyzed objectively using an ope...

The BACTEC Microbacteria Growth Indicator Tube (MGIT) 960 system was evaluated to determine how it compares with the BACTEC 460 radiometric system and solid media for recovery of Mycobacterium bovis from tissue samples. A total of 506 bovine lymph node samples were collected from abattoirs in the United States and Mexico between November 2003 and September 2004. Processed samples were inoculate...