Comparative study between using Lowenstein Jensen, Bio-FM media and mycobacteria growth indicator tube (MGIT) system in identification of Mycobacterium tuberculosis

Background/aim: Tuberculosis (TB) continues to be one of the most important infectious diseases threatening the human health. Culture systems are used for isolation of tuberculous bacilli as they are more sensitive than smear microscopy. The aim of the work was to evaluate the detection rate and time of Mycobacterium tuberculosis by using the Bio FM system and mycobacteria growth indicator tube (MGIT) system in comparison with the Lowenstein–Jensen medium.Methods: This study was carried out on a total 60 smear acid fast bacilli positive sputum samples obtained from patients attending the Chest Department and Outpatient Clinic of Benha University Hospital, Benha Chest Hospital, from June 2012 to September of the same year. Patients were classified into three groups: Group I: included 40 patients with fresh sputum smear +ve (new cases), Group II: included 13 relapsed cases and Group III: included 7 treatment failure cases. All sputum samples were cultured in parallel on Bio-FM, MGIT and LJ media. The mycobacterial detection rate and time were compared.Results: The mycobacteria recovery rate on MGIT, Bio-FM and LJ was not significantly different (respectively 98.3%, 95% and 93%, P > 0.05). The growth of M. tuberculosis bacilli was faster on MGIT than on Bio-FM (mean 10.7 ± 2.9 days, 11.1 ± 4.3 days, respectively vs. 23.6 ± 8.1 days for LJ), there was statistically significant difference between LJ and Bio-FM and LJ and MGIT. However there was no statistical significance when comparing MGIT and Bio-FM.Conclusion: MGIT and Bio-FM are good culture systems for accurate and rapid detection of M. tuberculosis