Original Research Article
Year: 2020 | Month: April | Volume: 10 | Issue: 4 | Pages: 46-51
Comparison of Ziehl-Neelsen Smear Microscopy and AFB Culture in a Resource Limited Setting from Various Clinical Samples
T. G. Pathrikar, V. P. Bansal, M. V. Mulay, H. S. Ghogare
Assistant Professor, Microbiology, MGM Medical College & Hospital, Aurangabad.
Corresponding Author: T.G. Pathrikar
ABSTRACT
Background: Tuberculosis is one of the leading causes of morbidity and mortality in the developing countries. It is considered a great challenge for clinical microbiologists to detect and identify mycobacterium tuberculosis. Ziehl-Neelsen (ZN) smear is a rapid diagnostic tool for TB, Lowenstein Jensen (LJ) medium culture is the golden diagnostic tool for TB in the developing countries.
Objectives: To evaluate the reliability and validity of ZN smear of acid fast bacilli when compared to the culture on LJ medium.
Design and setting:- This study was conducted from 1stApril 2016 to 31st march 2019 in the tuberculosis section of Microbiology department MGM Aurangabad, Maharashtra state.
Patients and Methods:- The comparative cross sectional study included patients visiting OPD clinics and wards of MGM medical college and hospital Aurangabad.
A total of 218 samples/specimens from various clinical sites were processed for both direct smear and culture. The direct smears were stained with ZN method [(1%) carbol fuchsin, (25%) sulphuric acid, (0.3%) methylene blue] according to RNTCP. Specimens were observed under 100x oil immersion lens, while the culture were inoculated on LJ medium which were collected aseptically and were expected to have no contaminants. Samples were decontaminated where ever applicable.
Results:-Out of total 218 patients 3(1.376%) were smear positive, while 35 (16.055%) were culture positive Out of the (03) smear positive specimens 1 (33.333%) was found to be growth positive on LJ culture. A total of 34 (15.596%) were negative on the smear but were found to the positive on LJ culture for mycobacterium tuberculosis. A total of 215 (98.623%) specimens were negative on the smear and LJ culture for mycobacterium tuberculosis.
Conclusion:- This study indicated low sensitivity of sputum smear direct microscopy for early diagnosis of TB, while LJ culture remains the golden standard modality.
Key words: Tuberculosis, ZN Smear, LJ Culture Golden Standard