ABSTRACT
Tuberculosis is a major public health problem worldwide and remains one of the most significant causes of death from an infectious agent. India contributes to 25.5% of the global new TB case detection. In recent times, emphasis has shifted from older phenotypically and biochemical methods of diagnosis to molecular methods such as GeneXpert MTB/RIF, a real time PCR that can detect MTB and rifampicin resistence simultaneously. Methods: This study aims at assessing the performance of acid fast bacilli (AFB) smear microscopy in comparison with GeneXpert MTB RIF, in the diagnosis of pulmonary tuberculosis. Study was a cross-sectional study carried out at the Department of Pulmonary Medicine, Muzaffarnagar Medical College, from January 2018 to April 2019. Result: The detection of MTB and rifampicin resistance using the Xpert MTB/RIF assay was assessed in 67 specimens from patients suspected of having pulmonary tuberculosis and compared with conventional smear microscopy. Out of these 67 sputum specimens, 38 samples were MTB positive by smear microscopy while 56 samples were MTB detected by Gene Xpert assay. Gene Xpert detected 18 additional tubercular cases and identify two cases of Rifampicin resistant MTB. Conclusion: Study show that there was no statistically significance in diagnostic value between GeneXpert and AFB smear microscopy in sputum samples however Gene Xpert MTB/RIF is useful method for rapid detection of MTB and Rifampicin resistance simultaneously.
ABSTRACT
Aim: To determine the correlation of accuracy of direct smear microscopy compared with BACTEC MGIT 960. Design: The study prospectively compare direct smear microscopy with BACTEC MGIT 960 using the reference standard, Lowenstein Jensen culture. Place and Duration: The study was conducted in Zankli Medical Centre, Abuja, between November 2004 and July 2005. Methodology: 340 suspected patients for Mycobacterium tuberculosis referred from direct observation therapy clinics located in six different government owned health facilities were referred to our facility. These patients; male (192) and female (148) were between the age of 10 and 64 years old. Three sputa samples were collected over two consecutive days and direct smear microscopy and culture were performed on these samples. Results: When compared with the reference standard, BACTEC MGIT 960 has a sensitivity and specificity of 100.0% and 56.4% respectively, and a negative predictive value of 100.0%; indicating the proportion of AFB negative participants were actually not infected with M. tuberculosis when tested with BACTEC MGIT 960. The sensitivity of direct microscopy was significantly lower than BACTEC MGIT 960 (84.9% versus 100%, p<0.001) and the specificity was significantly higher (96.6% versus 56.4%, p<0.001). Conclusions: For the purpose of effectiveness of tuberculosis program in developing countries, direct smear microscopy may still be relevant in the diagnosis of Mycobacterium tuberculosis.