Comparative evaluation of the bactec MGIT 960 [mycobacteria growth indicator tube] system with LJ solid medium for diagnosis of pulmonary tuberculosis

ABSTRACT

Tuberculosis [TB] is responsible for about one third of preventable deaths worldwide. Accurate and rapid diagnosis of tuberculosis is essential for controlling the spread of the disease caused by Mycobacterium tuberculosis. The aim of this study was to evaluate the Mycobacteria Growth Indicator Tube [[MGIT 960] [M960]] which is a fully automated, non-invasive, system for growth and detection of mycobacteria and Lowenstein-Jensen [LJ] media for the recovery of Mycobacterium tuberculosis from sputum samples. Out of 67 specimens processed, 60 isolates [89.5%] were recovered by M960 media while, 50 isolates [74.6%] were obtained by LJ. M960 as a single system detected 11 [16.4%] isolates more than L.J media while; L.J media detected 2 [2.9%] isolates [revealed no growth in MGIT 960]. In total, Out of these 67 specimens, 48 [71.6%] were positive by all methods [Z-N smear, culture on both LJ and MGIT broth] and 48 [71.6%] isolates also were obtained by the combined use of both culture methods. Average detection time of M960 and LJ media was 14.6 days [2-38] and 30.6 days [7-58] respectively. The contamination rates in our study were [2.9%] for M960 and [1.49%] for L.J media. In conclusion, comparable to LJ media, M960 system is a rapid and efficient method for diagnosis of pulmonary tuberculosis. But for maximum recovery of mycobacteria, a combination of both M960 and LJ media should be used