ABSTRACT
Introduction: The emergence of drug-resistant tuberculosis has made the current epidemic worse. It can be prevented if patients with drug resistant tuberculosis are identified rapidly and treated with a combination of effective drugs. The method of proportion; the reference method advocated by the WHO, is known to provide reliable results in agreement with the outcome of patients but the required time is 6-8 weeks. MGIT is a new system of detection of mycobacterial growth based on an enriched 7H9 medium and a fluorescent indicator quenched in the presence of oxygen
Objective: MGIT was evaluated for drug susceptibility testing to the four 1[st] line drugs [Isoniazide, Rifampicin, Streptomycin and Ethambutol], in comparison to the proportion method using Lowenstein-Jenesen media, for rapid detection of MDR-TB
Patients and Methods: 25 patients previously diagnosed as MDR-TB by the reference method; were included in this study. MGIT susceptibility testing was performed according to the manufacturer's recommendations
Results: Susceptibility testing for Isoniazide and Rifampicin using MGIT showed high efficiency; 96% and 88% respectively when compared with the "gold standard" the Proportion method. While susceptibility testing for Streptomycin and Ethambutol using MGIT showed a low efficiency; 80% and 64% respectively. Turnout time: Results were obtained within a range from 3-14 days with a mean time of 9.28 +/- 0.60421 days when using MGIT, while the results were obtained within a range of 21-42 days with a mean time of 33.4 +/- 1.2 days when using the Proportion method
Conclusion: The speed of obtaining the results is the main advantage of the test when compared with the Proportion method [standard method]. MGIT performed well in detection of resistant strains to both Isoniazide and Rifampicin. In contrast, MGIT performance in susceptibility testing to Streptomycin and Ethambutol was not that good and this points out to the need for further studies