monitoring of patient samples to identify the positive ones and refers safe, on-board incubation. MGIT utilizes a modified 7H9 Middlebrook broth base with 0.25% glycerol (7 ml) with an oxygen quenching fluorescent sensor embedded in silicon at the bottom to detect microbial growth directly from clinical specimens. [2] Species identification of all isolated mycobacteria can be done using a ρ-nitro benzoic acid (PNBA) from MGIT positive vials. PNBA inhibits mycobacteria belonging to the M.

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... losis complex while other mycobacteria show either slight or no inhibition. The alternative option is commercial molecular techniques, as probe hybridization is very expensive for routine labs in developing countries. In this study, we compared the recovery rate and time of MGIT 960 system versus the conventional L.J media routinely used for AFB culture across India. The efficiency of PNBA assay for identification of M. tuberculosis complex was analysed using 440 culture isolates and results were compared to a ρ-nitro-α-acetylamino-β-hydroxypropiophenone (NAP) test on BACTEC 460 TB system, an in-house Reverse Line Blot Hybridization (RLBH) assay and sequencing. Materials and Methods All clinical specimens were digested and decontaminated by the standard N-acetyl-L-cysteine-NaOH method. [6] The sediment was suspended in 1 ml of sterile phosphatebuffered saline (pH 6.8). 0.5 ml of the processed specimen was then inoculated into MGIT 960 vials supplemented as described by the manufacturer, and 0.2 ml onto L.J medium slants. All inoculated MGIT vials were incubated in the MGIT 960 instrument either until they were flagged positive Abstract Aim: To evaluate the performance of an automated BACTEC MGIT 960, a non-radioactive, non-invasive liquid culture system for cultivation of M. tuberculosis complex in terms of recovery rate and time. Materials and Methods: From 597 specimens were processed using the MGIT 960 system and the results were compared with conventional L.J medium. We standardised ρ-nitro benzoic acid (PNBA) assay on MGIT 960 TB system for identification of M. tuberculosis complex and evaluated its usefulness by comparing the results with an in-house molecular assay and sequencing. Results and Discussion: Of the total 6143 (42%) isolates positive for M. tuberculosis complex, 6015 (41%) were positive by MGIT 960 TB system. In contrast, 3526 (24%) M. tuberculosis complex isolates grew on the conventional L.J medium. The mean turn around time for mycobacterial growth in smear-positive specimens was nine days for MGIT 960, and 38 days for L.J. medium whereas in smear negative specimens it was 16 days by MGIT vs. 48 days by L.J. Conclusion: MGIT 960 system with PNBA assay for identification of M. tuberculosis complex is a rapid and useful method in laboratories processing a large number of specimens.