Healthline (Jul 2020)
Role of CB-NAAT in Diagnosis of Mycobacterial Tuberculosis and Rifampicin Resistance among Key Population under Programmatic Condition in Gujarat, India
Abstract
Introduction : India is the country with the highest burden of TB infection. The World Health Organization has endorsed the Gene Xpert MTB/RIF assay for rapid detection of tuberculosis with rifampicin resistance. Testing specimens with CB-NAAT can detect pauci bacillary mycobacterial tuberculosis which is potentially contribute to microbiological confirmation of tuberculosis. Diagnosing tuberculosis (TB) in people living with HIV/AIDS (PLHIV) , paediatric age group and extrapulmonary samples is challenging as microscopy is negative due to low bacillary load .TB culture is a slow method which takes 2-6 weeks for growth of the mycobacteria. Objective : To assess the the role of Cartridge based nucleic acid amplification test (CBNAAT) to diagnose TB and rifampicin resistance in PLHIV , paediatric age group and extrapulmonary samples. Method : The study is based on the secondary analysis of data derived from testing by Xpert MTB/RIF testing among presumptive TB cases of HIV/AIDS (PLHIV), paediatric age group and extrapulmonary samples in Gujarat. Under this study, 28,304 presumptive TB cases of HIV/AIDS (PLHIV), paediatric age group and extrapulmonary samples were tested between January to September 2019. Results: Overall, 1,40,177 specimens were tested, of which 10,018 (7.14%) samples were PLHIV presumptive TB , 7,380 (5.26%)samples were Paediatric Presumptive TB and 10,906(7.78%) samples were extrapulmonary Presumptive TB. These 28,304 presumptive cases , in 3994(14.11%) cases TB detected. Out of these 3994 TB detected cases , 1068 were PLHIV Presumptive TB , 724 were paediatic presumptive TB and 1987 were extrapulmonary presumptive TB. Total 2220 rifampicin resistant TB cases were detected from January 2019 to September 2019 , of which 288(10.27%) were rifampicin resistant TB in key population .Out of these 288 rifampicin resistant TB cases 63 were PLHIV Presumptive TB ,47 were paediatic presumptive TB and 178 were extrapulmonary presumptive TB cases. Conclusion : CBNAAT has advantages of rapid case detection bacteriologically confirmed TB in less than 2 hours and simultaneously detecting rifampicin resistance in PLHIV , paediatic age group and extrapulmonary samples in which bacillary load is very low .
