Molecular Approaches for Detection of Rifampin-Resistant Mycobacterium tuberculosis and Its Associated Risk Factors among General Population

Abstract

GeneXpert MTB/RIF is a molecular technique for the diagnosis of tuberculosis. This method not only detects M. tuberculosis but also identifies the absence or presence of different drug resistant mutations in DNA fragments like rifampicin resistance. In this study, about 200 septum samples were collected from tuberculosis suspected people of Isfandyar Bukhari District Head Quarter Hospital Attock for screening and determination of Mycobacterium tuberculosis and multi-drug-resistant tuberculosis. The samples were screened for the presence of M. tuberculosis using Fluorescence Microscopy staining followed by GeneXpert MTB/RIF assay. The results were further confirmed by Line Probe Assay and Mycobacterium Growth Indicator Tube 960 techniques. In a total of 200 samples, 45(22.5%) were found positive, 155 (77.5%) were classified negative on culture while 38(19%) were positive and 162(81%) were negative on FM, 33(16.5%) were positive and 167(83.5%) were negative on ZN staining microscopy and 47(23.5%) were noted positive and 153 (76.5%) were negative on GeneXpert. The overall sensitivity of GeneXpert was 07% higher than that of smear microscopy and 4.2 % higher than culture.Different risk factors reported for TB are; malnutrition (23.40%), health care workers (14.89%), immunosuppression (12.76%), unimmunized with Bacille Calmette-Guérin (BCG) vaccine and contact with infected persons (10.63%), diabetes mellitus (8.51%), poverty and foreign-born children are (4.2%). It is concluded that the most common risk factor for TB was malnutrition (23.40%) and the foreign-born children (4.2%) were least affected. GeneXpert assay for identification of tuberculosis was found more sensitive than fluorescence microscopy and for isolation of MTB and rifampicin resistance, GeneXpert RIF assay can efficiently be usedwhich is simple, robust and efficient with minimum handling technique.