A study on prevalence of rifampicin resistance by Gene Xpert with clinico-radiological correlation in previously treated pulmonary tuberculosis patients

BACKGROUND: The drug resistant tuberculosis is a great threat to mankind. The rifampicin resistance is a good predictor of multidrug resistant tuberculosis. The Gene Xpert is an excellent diagnostic tool for rapid detection of Mycobacterium tuberculosis and rifampicin resistance. AIMS & OBJECTIVES: The aims & objectives of the study were to find out the prevalence of rifampicin resistance among smear positive and smear negative previously treated pulmonary tuberculosis patients and to correlate clinico-radiological profile with rifampicin resistance. MATERIALS & METHODS: The prospective analytic study was conducted in 200 presumptive TB patients with past history of anti-tuberculosis treatment for one month or more. The Gene Xpert test (CBNAAT) was performed. The results were analysed using appropriate statistical tests. RESULTS: Out of 200 study population, Mycobacterium tuberculosis was detected in 159 (79.5%) cases by Gene Xpert. Rifampicin resistance was detected in 36 (22.64%) out of 159 cases. The prevalence of rifampicin resistance among sputum positive previously treated pulmonary tuberculosis was 25.21% (31/123) whereas the prevalence among previously treated sputum negative pulmonary tuberculosis was 13.8% (5/36). Out of 57 relapse cases, 26 failure cases, 40 treatment after default cases and 36 other cases, rifampicin resistance was detected in 9 (15.79%), 12 (46.15%), 10 (25%) and 5 (13.88%) patients respectively. The statistically significant correlation was found between failure cases and rifampicin resistance (P<0.05). CONCLUSION: The overall prevalence of rifampicin resistance is 22.64% among previously treated pulmonary tuberculosis. The failure case is significantly associated with rifampicin resistance.