Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.

Multidrug resistant (MDR) tuberculosis is caused by Mycobacterium tuberculosis resistant to isoniazid and rifampicin, the two most effective drugs used in tuberculosis therapy. Here, we investigated the mechanism by which resistance towards isoniazid develops and how overexpression of efflux pumps f...

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Autores principales:	Diana Machado, Isabel Couto, João Perdigão, Liliana Rodrigues, Isabel Portugal, Pedro Baptista, Bruno Veigas, Leonard Amaral, Miguel Viveiros
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2012
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/2d3b170685344caea5d7def9047f6f1c
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spelling	oai:doaj.org-article:2d3b170685344caea5d7def9047f6f1c2021-11-18T07:23:01ZContribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.1932-620310.1371/journal.pone.0034538https://doaj.org/article/2d3b170685344caea5d7def9047f6f1c2012-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22493700/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203Multidrug resistant (MDR) tuberculosis is caused by Mycobacterium tuberculosis resistant to isoniazid and rifampicin, the two most effective drugs used in tuberculosis therapy. Here, we investigated the mechanism by which resistance towards isoniazid develops and how overexpression of efflux pumps favors accumulation of mutations in isoniazid targets, thus establishing a MDR phenotype. The study was based on the in vitro induction of an isoniazid resistant phenotype by prolonged serial exposure of M. tuberculosis strains to the critical concentration of isoniazid employed for determination of drug susceptibility testing in clinical isolates. Results show that susceptible and rifampicin monoresistant strains exposed to this concentration become resistant to isoniazid after three weeks; and that resistance observed for the majority of these strains could be reduced by means of efflux pumps inhibitors. RT-qPCR assessment of efflux pump genes expression showed overexpression of all tested genes. Enhanced real-time efflux of ethidium bromide, a common efflux pump substrate, was also observed, showing a clear relation between overexpression of the genes and increased efflux pump function. Further exposure to isoniazid resulted in the selection and stabilization of spontaneous mutations and deletions in the katG gene along with sustained increased efflux activity. Together, results demonstrate the relevance of efflux pumps as one of the factors of isoniazid resistance in M. tuberculosis. These results support the hypothesis that activity of efflux pumps allows the maintenance of an isoniazid resistant population in a sub-optimally treated patient from which isoniazid genetically resistant mutants emerge. Therefore, the use of inhibitors of efflux should be considered in the development of new therapeutic strategies for preventing the emergence of MDR-TB during treatment.Diana MachadoIsabel CoutoJoão PerdigãoLiliana RodriguesIsabel PortugalPedro BaptistaBruno VeigasLeonard AmaralMiguel ViveirosPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 7, Iss 4, p e34538 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Diana Machado Isabel Couto João Perdigão Liliana Rodrigues Isabel Portugal Pedro Baptista Bruno Veigas Leonard Amaral Miguel Viveiros Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.
description	Multidrug resistant (MDR) tuberculosis is caused by Mycobacterium tuberculosis resistant to isoniazid and rifampicin, the two most effective drugs used in tuberculosis therapy. Here, we investigated the mechanism by which resistance towards isoniazid develops and how overexpression of efflux pumps favors accumulation of mutations in isoniazid targets, thus establishing a MDR phenotype. The study was based on the in vitro induction of an isoniazid resistant phenotype by prolonged serial exposure of M. tuberculosis strains to the critical concentration of isoniazid employed for determination of drug susceptibility testing in clinical isolates. Results show that susceptible and rifampicin monoresistant strains exposed to this concentration become resistant to isoniazid after three weeks; and that resistance observed for the majority of these strains could be reduced by means of efflux pumps inhibitors. RT-qPCR assessment of efflux pump genes expression showed overexpression of all tested genes. Enhanced real-time efflux of ethidium bromide, a common efflux pump substrate, was also observed, showing a clear relation between overexpression of the genes and increased efflux pump function. Further exposure to isoniazid resulted in the selection and stabilization of spontaneous mutations and deletions in the katG gene along with sustained increased efflux activity. Together, results demonstrate the relevance of efflux pumps as one of the factors of isoniazid resistance in M. tuberculosis. These results support the hypothesis that activity of efflux pumps allows the maintenance of an isoniazid resistant population in a sub-optimally treated patient from which isoniazid genetically resistant mutants emerge. Therefore, the use of inhibitors of efflux should be considered in the development of new therapeutic strategies for preventing the emergence of MDR-TB during treatment.
format	article
author	Diana Machado Isabel Couto João Perdigão Liliana Rodrigues Isabel Portugal Pedro Baptista Bruno Veigas Leonard Amaral Miguel Viveiros
author_facet	Diana Machado Isabel Couto João Perdigão Liliana Rodrigues Isabel Portugal Pedro Baptista Bruno Veigas Leonard Amaral Miguel Viveiros
author_sort	Diana Machado
title	Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.
title_short	Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.
title_full	Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.
title_fullStr	Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.
title_full_unstemmed	Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.
title_sort	contribution of efflux to the emergence of isoniazid and multidrug resistance in mycobacterium tuberculosis.
publisher	Public Library of Science (PLoS)
publishDate	2012
url	https://doaj.org/article/2d3b170685344caea5d7def9047f6f1c
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Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis.

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