Comparative Analysis of Sputum Microscopy and Gene xpert Technique for Pulmonary Tuberculosis Along with Rifampicin Resistant in Tertiary Health Facility, Udaipur

Abstract

Introduction: Mycobacterium tuberculosis (MTB) rapid identification, differentiation of MTB from nontuberculous mycobacteria (NTM) along with its resistance to rifampicin is necessary in mycobacterial diseases management. Culture beingthe “gold standard” for the detection of MTB, is time consuming. Smear microscopy, inspite of its rapidity and low cost, has poor sensitivity for the detection of acid-fast bacilli (AFB). GeneXpert MTB/RIF assay, a real-time PCR based rapid diagnostic method can simultaneously detect M. tuberculosis and its resistance or sensitivity to Rifampicin. Hence, we aim to compare the performance of GeneXpert assay with ZN smear along with rifampicin resistant pattern in tertiary health facility. Aim: The Study aims to analyze patients’ respiratory samples. Objectives:1.Comparative analysis of GeneXpert and ZN Smear for detection of Mycobacterium tuberculosis2.To find out the sensitivity of GeneXpertAssay method along with Ziehl-Neelsen method in Tuberculosis infection diagnosis3.To determine the prevalence of Rifampicin resistance. Materials and Methods: This study included 1857 suspected tuberculosis patients,who had their sputum samples tested for ZN smear microscopy and GeneXpert during the period January to December 2019. The results of ZN smear microscopy and Gene Xpert was collected for data analysis. Results: A total of 1857 of patients were evaluated in final analysis.The Gene xpert performance was compared with Ziehl Neelsen technique. Out of the 1857 persons, 709 were smear Positive (38.2%) and 1148 were smear negative (61.8%), while for the Genexpert873 (47.01%) were MTBdetected, 984 (52.98%) MTB not detected. Out of 873 were 816 RIF (82.92%) Sensitive and 57 (5.79%) RIF resistance. 667 (35.91%) were TB Positive with both techniques, 206 (14%) were GeneXpert positive but ZN staining technique negative,942 (50.72%) were negative with both methods and 42 (2.26%) was ZN stain Positive but GeneXpert negative. Conclusions: The GeneXpertis a cartridge-based nucleic acid amplification test (NAAT) is best available for simultaneous rapid tuberculosis diagnosis and antibiotic sensitivity test.Accuracy and negative predictive value of GeneXpert was found to be better than AFB staining. Thus, a negative GeneXpert test can rule out TB. Further, the test may helpful in diagnosis of TB in patients likely to be missed by traditional tests. Also,positive ZN Stain and negative GeneXpert results indicate the presence of NTM. However, when compared to ZN smear, GeneXpert is expensive and needs sophisticated instrument.