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Correlation of inhA mutations and ethionamide susceptibility: Experience from national reference center for tuberculosis

BACKGROUND: Detection of ethionamide (ETH) resistance is crucial as it is part of antitubercular regime. It is crucial to examine the role of inhA gene mutations as a surrogate marker for the detection of ETH resistance, in the Indian context. The present retrospective study was designed with this o...

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Autores principales: Sarin, Rohit, Bhalla, Manpreet, Kumar, Gavish, Singh, Anjali, Myneedu, Vithal Prasad, Singhal, Ritu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Wolters Kluwer - Medknow 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8614619/
https://www.ncbi.nlm.nih.gov/pubmed/34747732
http://dx.doi.org/10.4103/lungindia.lungindia_120_21
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author Sarin, Rohit
Bhalla, Manpreet
Kumar, Gavish
Singh, Anjali
Myneedu, Vithal Prasad
Singhal, Ritu
author_facet Sarin, Rohit
Bhalla, Manpreet
Kumar, Gavish
Singh, Anjali
Myneedu, Vithal Prasad
Singhal, Ritu
author_sort Sarin, Rohit
collection PubMed
description BACKGROUND: Detection of ethionamide (ETH) resistance is crucial as it is part of antitubercular regime. It is crucial to examine the role of inhA gene mutations as a surrogate marker for the detection of ETH resistance, in the Indian context. The present retrospective study was designed with this objective. SUBJECTS AND METHODS: The study was conducted in National Reference Laboratory within the tertiary care institute from January 1, 2018, to June 30, 2019, over 18 months duration. A total of 6612 sputum samples from presumptive multidrug-resistant tuberculosis (TB) patients were received from four districts of Delhi, outdoor and inpatients. Line probe assay (LPA) was performed for smear-positive or culture-positive samples for Mycobacterium tuberculosis. All isolates found to be INH resistant by LPA were cultured and phenotypic susceptibility to ETH was conducted for selected isolates as per the guidelines. RESULTS: A total of 246 isolates were analyzed, for which phenotypic susceptibility to ETH and mutations in inhA were available. ETH resistance was detected among 87/108 (80.5%) isolates with inhA mutation. Sensitivity and specificity of inhA mutation for detection of ETH resistance were 80.5% and 83.8%, respectively. No inhA mutation was detected in 29/116 (25%) ETH-resistant isolates in our study, whereas ETH was found to be phenotypically susceptible in spite of the presence of inhA mutation among 21/130 (16.1%) isolates. CONCLUSIONS: Mutations in inhA gene in LPA predict ETH resistance with fairly good sensitivity and specificity. However, it is imperative to perform phenotypic detection of ETH resistance at proper concentration, in addition to detecting inhA mutation.
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spelling pubmed-86146192021-12-13 Correlation of inhA mutations and ethionamide susceptibility: Experience from national reference center for tuberculosis Sarin, Rohit Bhalla, Manpreet Kumar, Gavish Singh, Anjali Myneedu, Vithal Prasad Singhal, Ritu Lung India Original Article BACKGROUND: Detection of ethionamide (ETH) resistance is crucial as it is part of antitubercular regime. It is crucial to examine the role of inhA gene mutations as a surrogate marker for the detection of ETH resistance, in the Indian context. The present retrospective study was designed with this objective. SUBJECTS AND METHODS: The study was conducted in National Reference Laboratory within the tertiary care institute from January 1, 2018, to June 30, 2019, over 18 months duration. A total of 6612 sputum samples from presumptive multidrug-resistant tuberculosis (TB) patients were received from four districts of Delhi, outdoor and inpatients. Line probe assay (LPA) was performed for smear-positive or culture-positive samples for Mycobacterium tuberculosis. All isolates found to be INH resistant by LPA were cultured and phenotypic susceptibility to ETH was conducted for selected isolates as per the guidelines. RESULTS: A total of 246 isolates were analyzed, for which phenotypic susceptibility to ETH and mutations in inhA were available. ETH resistance was detected among 87/108 (80.5%) isolates with inhA mutation. Sensitivity and specificity of inhA mutation for detection of ETH resistance were 80.5% and 83.8%, respectively. No inhA mutation was detected in 29/116 (25%) ETH-resistant isolates in our study, whereas ETH was found to be phenotypically susceptible in spite of the presence of inhA mutation among 21/130 (16.1%) isolates. CONCLUSIONS: Mutations in inhA gene in LPA predict ETH resistance with fairly good sensitivity and specificity. However, it is imperative to perform phenotypic detection of ETH resistance at proper concentration, in addition to detecting inhA mutation. Wolters Kluwer - Medknow 2021 2021-10-26 /pmc/articles/PMC8614619/ /pubmed/34747732 http://dx.doi.org/10.4103/lungindia.lungindia_120_21 Text en Copyright: © 2021 Indian Chest Society https://creativecommons.org/licenses/by-nc-sa/4.0/This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.
spellingShingle Original Article
Sarin, Rohit
Bhalla, Manpreet
Kumar, Gavish
Singh, Anjali
Myneedu, Vithal Prasad
Singhal, Ritu
Correlation of inhA mutations and ethionamide susceptibility: Experience from national reference center for tuberculosis
title Correlation of inhA mutations and ethionamide susceptibility: Experience from national reference center for tuberculosis
title_full Correlation of inhA mutations and ethionamide susceptibility: Experience from national reference center for tuberculosis
title_fullStr Correlation of inhA mutations and ethionamide susceptibility: Experience from national reference center for tuberculosis
title_full_unstemmed Correlation of inhA mutations and ethionamide susceptibility: Experience from national reference center for tuberculosis
title_short Correlation of inhA mutations and ethionamide susceptibility: Experience from national reference center for tuberculosis
title_sort correlation of inha mutations and ethionamide susceptibility: experience from national reference center for tuberculosis
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8614619/
https://www.ncbi.nlm.nih.gov/pubmed/34747732
http://dx.doi.org/10.4103/lungindia.lungindia_120_21
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