Viable Staining for Detecting Mycobacterium Pulmonary Tuberculosis in Vulnerable Population

Abstract

Background: Diagnosis of pulmonary tuberculosis (PTB) is the major concern of proper diagnosis and for effective treatment of PTB. Despite the recent advancement in diagnostic methods, the smear microscopy remains the gold standard for the diagnosis of PTB in high burden countries. Design: This study, therefore, aimed at assessing the diagnostic performance of fluorescein diacetate (FDA) and Ziehl–Neelsen (ZN) staining techniques in the diagnosis of PTB for vulnerable group of population HIV, smoker, health care workers, and malnutrition people and confirmed with Mycobacterium Growth Indicator Tube (MGIT) liquid culture to check the viability. Samples were collected from Intermediate Reference Laboratory, Karnataka, from November 2019 to March 2020. A total of 350 samples were collected and these were stained using ZN method as per National Tuberculosis Elimination Program norms and FDA method followed by liquid culture using the MGIT 960 to check for the viability of the bacilli and correlate with the results of the FDA viability staining method. Results: The study demonstrates that the sensitivity and specificity of FDA viable fluorescent staining to that of liquid MGIT culture were 98.6% and 100%, respectively, while those of ZN staining were 55.8% and 100%, respectively. Conclusion: Hence, we concluded that the FDA staining technique is a more sensitive test for checking the viability of AFB among PTB suspect, as compared to the conventional ZN-stained smear observation.