AbstractIntroduction: The global burden TB remains enormous. Most of them occur in resource limited settings. Smear microscopy is the cornerstone but it has only modest sensitivity and poor positive predictive value. Culture is the gold standard for final determination but its results typically not available for 2-6 weeks. Given the inability to elucidate the drug resistance and rapid detection by these methods, preventing the patients from obtaining the appropriate and timely therapy at point of need.
Gene Xpert system offers an overall sensitivity that is higher than AFB smear microscopy, and also provides genetic information about mutations that confer antibiotic resistance to the primary antibiotic Rifampicin. Here, we describe an assessment of the Gene drive MTB/RIF assay using sputum samples and comparing its performance against standard AFB smear microscopy.
Objectives: 1. To assess the diagnostic usefulness of Gene-Xpert MTB/ RIF assay technique in management of tuberculosis. 2. To detect the prevalence of rifampicin resistance among smear positive and smear negative cases.
Material and Methods: This is an observational study conducted in the department of microbiology. Sputum sample of clinically suspected cases of pulmonary tuberculosis will be collected under all aseptic precaution and subjected to Gene Xpert for MTB/RIF detection after AFB microscopy.
Result: 33(22.29%) Sputum/BAL samples were AFB smear positive and 115(77.70%) % were negative. In Gene Xpert MTB/RIF assay 63(42.56%) were MTB positive and 85(57.43%) were MTB negative. Chi square test was applied; P value is <0.001. All results are highly significant. The Gene Xpert MTB/RIF Assay also detected RIF resistant 09(6.0%) and RIF susceptible 53(35.81%) cases and 01(0.67%) indeterminate case.
Conclusion: CBNAAT helps in increased case detection in lesser time to diagnose pulmonary tuberculosis as compared to conventional sputum microscopy. It also detects the rifampicin resistance with high specificity to start early treatment.