Revisiting the susceptibility testing of Mycobacterium tuberculosis to ethionamide in solid culture medium.

Lakshmi, Rajagopalan and Ramachandran, Ranjani and Kumar, D Ravi and Sundar, A Syam and Radhika, G and Rahman, Fathima and Selvakumar, N and Kumar, Vanaja (2015) Revisiting the susceptibility testing of Mycobacterium tuberculosis to ethionamide in solid culture medium. The Indian journal of medical research, 142 (5). pp. 538-42. ISSN 0971-5916

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Abstract

BACKGROUND & OBJECTIVES Increase in the isolation of drug resistant phenotypes of Mycobacterium tuberculosis necessitates accuracy in the testing methodology. Critical concentration defining resistance for ethionamide (ETO), needs re-evaluation in accordance with the current scenario. Thus, re-evaluation of conventional minimum inhibitory concentration (MIC) and proportion sensitivity testing (PST) methods for ETO was done to identify the ideal breakpoint concentration defining resistance. METHODS Isolates of M. tuberculosis (n=235) from new and treated patients were subjected to conventional MIC and PST methods for ETO following standard operating procedures. RESULTS With breakpoint concentration set at 114 and 156 µg/ml, an increase in specificity was observed whereas sensitivity was high with 80 µg/ml as breakpoint concentration. Errors due to false resistant and susceptible isolates were least at 80 µg/ml concentration. INTERPRETATION & CONCLUSIONS Performance parameters at 80 µg/ml breakpoint concentration indicated significant association between PST and MIC methods.

Affiliation:	ICMR-National Institute for Research in Tuberculosis
Item Type:	Article
Uncontrolled Keywords:	Drug resistance - ethionamide - MIC method - Mycobacterium tuberculosis - proportion sensitivity testing
Subjects:	Tuberculosis > Laboratory Research > Bacteriological
Divisions:	Basic Science Research > Bacteriology
Depositing User:	Dr. Rathinasabapati R
Date Deposited:	28 Sep 2022 11:04
Last Modified:	29 Sep 2022 09:09
URI:	http://eprints.nirt.res.in/id/eprint/1380

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