Reduced detection by Ziehl-Neelsen method of acid-fast bacilli in sputum samples preserved in cetylpyridinium chloride solution

Selvakumar, N and Sudhamathi, S and Duraipandian, M and Frieden, T R and Narayanan, P R (2004) Reduced detection by Ziehl-Neelsen method of acid-fast bacilli in sputum samples preserved in cetylpyridinium chloride solution. International Journal of Tuberculosis and Lung Disease, 8 (2). pp. 248-252. ISSN Print: 1027-3719; Online: 1815-7920

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Abstract

SETTING: Twelve health facilities implementing the DOTS strategy, and the Tuberculosis Research Centre (TRC), Chennai, India. OBJECTIVE: To determine the detection rates using Ziehl-Neelsen (ZN) and auramine-phenol to stain acidfast bacilli (AFB) in sputum samples stored in cetylpyridinium chloride (CPC) solution. METHODS: Two smears were prepared from each of 988 sputum samples collected in CPC and randomly allocated, one to ZN and the other to auramine-phenol staining. All samples were processed for culture of Mycobacterium tuberculosis. RESULTS: A significantly higher proportion of samples were negative using the ZN method compared to the auramine-phenol method (74.5% vs. 61.8%, McNamara’s paired �2 test; P � 0.001). Among 377 samples that were positive using auramine-phenol, 44% were negative using ZN. There were more culture-positive, smearnegative samples in ZN (52.7%) than in auraminephenol (30%); the difference attained statistical significance (McNemar’s paired �2 test; P � 0.00004). Using ZN, of the 104 smears made immediately after collection, 52 were positive for AFB, of which only 35 (67.3%) were positive after storage in CPC; the reduction in the number of positive smears attained statistical significance (McNemar’s paired �2 test; P � 0.004). CONCLUSION: Detection of AFB in sputum samples preserved in CPC is significantly reduced using ZN staining.

Item Type:	Article
Uncontrolled Keywords:	Mycobacterium tuberculosis; AFB; Ziehl-Neelsen; cetylpyridinium chloride
Subjects:	Tuberculosis > Laboratory Research > Bacteriological
Divisions:	Basic Science Research > Bacteriology
Depositing User:	Dr. Rathinasabapati R
Date Deposited:	21 Nov 2013 10:22
Last Modified:	09 Mar 2016 10:32
URI:	http://eprints.nirt.res.in/id/eprint/666

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