Evaluation of the effectiveness of BACTEC MGIT 960 for the detection of mycobacteria in Bangladesh

Tuberculosis [TB] caused by Mycobacterium tuberculosis has been identified as a re-emerging infectious disease with public health importance globally. Exploitation of new laboratory techniques for precise identification of mycobacteria in clinical specimens is of great importance to improve the diagnosis as part of the global TB control efforts. The current study was conducted for the evaluation of BACTEC MGIT 960 method in comparison with Lowenstein-Jensen [LJ] culture and light emitting diode [LED] fluorescence microscopy for isolation of mycobacteria among TB suspects from Bangladesh. A total of 421 specimens were tested with these methods. Among the tested samples, 3.6% [n = 15] were LED fluorescence microscopy positive; while 18 [4.2%] and 45 [10.6%] were recovered from LJ and MGIT 960 culture. The relative positivity found through MGIT 960 system were 60% and 66.7% higher than that of LJ culture and LED fluorescence microscopy, respectively. Recovery rate of Mycobacterium tuberculosis complex [[MTC], 21 by MGIT and 16 by LJ culture] and non-tubercular mycobacteria [[NTM], 24 by MGIT and 2 by LJ culture] by MGIT 960 was 24% and 96% greater, respectively than LJ culture. Moreover, MGIT 960 was found to be highly sensitive [100%], specific [93.3%], accurate [93.6%] and a more rapid method in detecting mycobacteria when compared with LJ culture. Extended recovery of NTM and MTC through MGIT 960 urged frequent application of this method to detect mycobacteria more effectively and rapidly

Comparisons among the diagnostic methods used for the detection of extra-pulmonary tuberculosis in Bangladesh

The present study was an attempt to establish a suitable method for the effective diagnosis of extra-pulmonary tuberculosis in Bangladesh. In this regard, detection of Mycobacterium tuberculosis from 390 different extra-pulmonary specimens was performed by Bright-Field microscopy, light-emitting diode fluorescence microscopy and Lowenstein-Jensen culture methods, followed by an extensive comparison among these methods. M. tuberculosis was detected in 53 cases through the conventional Lowenstein-Jensen culture method; 49 cases were detected under Bright-Field microscope, whereas the light-emitting diode fluorescence microscopy detected 64 cases. Out of 53 culture-positive isolates, 12 were found to be multi-drug resistant. Light-emitting diode fluorescence microscopy was found to be more sensitive and effective than both the Bright-Field microscopy and the Lowenstein- Jensen culture methods. Incidentally, light-emitting diode fluorescence microscopy appeared imperative to detecting the multi-drug resistant tuberculosis.