Evaluation of the BACTEC MGIT 960 TB with Solid Media for Recovery of Mycobacteria from Extrapulmonary Specimens in South Tunisia

The slow growth of M. tuberculosis complex is a major challenge for TB diagnosis, hence the importance of using media to obtain quick results. We compared the system MGIT960 to solid media: LJ and Coletsos in the diagnosis of extrapulmonary tuberculosis. A total of 634 extrapulmonary samples were processed for direct AFB smear examination, and culture on MGIT960 and solid media. 98 strains were isolated by the three media (15.4%). The mycobacterial recovery rate was 93.8%, 77.5% and 70.4% respectively for MGIT960, LJ and Coletsos media. The mean turnaround time for mycobacterial growth for MGIT960 was 18.5 ± 7.6 days. It was respectively 44.8 ± 19.3 and 42.8 ± 19 days for LJ and Coletsos media. Unlike most studies, the MGIT960 contamination rate (1.7%) was lower than that of solid media (2.2% for LJ and 2.5% for Coletsos). The MGIT 960 offers several advantages: speed, sensitivity and ease of use.