Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosis
Background: Tuberculosis is one of the most prevalent diseases in Pakistan. Pakistan has the highest burden of MDR-TB in the Eastern Mediterranean region. Ethionamide is an anti-tuberculous drug frequently used to treat MDR-TB. Its drug susceptibility testing is not easily available in resource limi...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Wolters Kluwer Medknow Publications
2017-01-01
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| Series: | International Journal of Mycobacteriology |
| Subjects: | |
| Online Access: | http://www.ijmyco.org/article.asp?issn=2212-5531;year=2017;volume=6;issue=2;spage=167;epage=170;aulast=Qamar |
| _version_ | 1818518631586201600 |
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| author | Salima Qamar Joveria Q Farooqi Kausar Jabeen Rumina Hasan |
| author_facet | Salima Qamar Joveria Q Farooqi Kausar Jabeen Rumina Hasan |
| author_sort | Salima Qamar |
| collection | DOAJ |
| description | Background: Tuberculosis is one of the most prevalent diseases in Pakistan. Pakistan has the highest burden of MDR-TB in the Eastern Mediterranean region. Ethionamide is an anti-tuberculous drug frequently used to treat MDR-TB. Its drug susceptibility testing is not easily available in resource limited settings. Since it acts on the same target protein as isoniazid (inhA protein encoded by inhA gene), we sought to find out if phenotypic isoniazid resistance can be a marker of ethionamide resistance. Materials and Methods: This was a retrospective observational study conducted at the Aga Khan University hospital section of microbiology. Data was retrieved between 2011 to 2014 for all culture positive MTB strains. All culture positive MTB isolates with susceptibilities to isoniazid and ethionamide recorded were included in the study. Isoniazid and ethionamide susceptibilities were performed using agar proportion method on Middlebrook 7H10 agar. Rate of Ethionamide resistance between low-level isoniazid resistant, high level isoniazid resistant and isoniazid sensitive MTB was compared. Results: A total of 11,274 isolates were included in the study. A statistically significant association (P < 0.001) was found between Ethionamide resistance and low-level isoniazid resistance (26.6%) as compared to high-level isoniazid resistance (8.85%) and isoniazid sensitivity (0.71%) in MTB strains. However this association was not seen in XDR-TB strains. Conclusion: Low level isoniazid resistance may be used as marker for phenotypic ethionamide resistance and hence guide clinicians' choice of antituberculous agent for MDR-TB in Pakistan. Further studies involving detection of genotypic association of isoniazid and ethionamide susceptibilities are needed before a final conclusion can be derived. |
| first_indexed | 2024-12-11T01:12:47Z |
| format | Article |
| id | doaj.art-8bc4ab6154824829b5e03e5adb4c5959 |
| institution | Directory Open Access Journal |
| issn | 2212-5531 2212-554X |
| language | English |
| last_indexed | 2024-12-11T01:12:47Z |
| publishDate | 2017-01-01 |
| publisher | Wolters Kluwer Medknow Publications |
| record_format | Article |
| series | International Journal of Mycobacteriology |
| spelling | doaj.art-8bc4ab6154824829b5e03e5adb4c59592022-12-22T01:25:59ZengWolters Kluwer Medknow PublicationsInternational Journal of Mycobacteriology2212-55312212-554X2017-01-016216717010.4103/ijmy.ijmy_34_17Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosisSalima QamarJoveria Q FarooqiKausar JabeenRumina HasanBackground: Tuberculosis is one of the most prevalent diseases in Pakistan. Pakistan has the highest burden of MDR-TB in the Eastern Mediterranean region. Ethionamide is an anti-tuberculous drug frequently used to treat MDR-TB. Its drug susceptibility testing is not easily available in resource limited settings. Since it acts on the same target protein as isoniazid (inhA protein encoded by inhA gene), we sought to find out if phenotypic isoniazid resistance can be a marker of ethionamide resistance. Materials and Methods: This was a retrospective observational study conducted at the Aga Khan University hospital section of microbiology. Data was retrieved between 2011 to 2014 for all culture positive MTB strains. All culture positive MTB isolates with susceptibilities to isoniazid and ethionamide recorded were included in the study. Isoniazid and ethionamide susceptibilities were performed using agar proportion method on Middlebrook 7H10 agar. Rate of Ethionamide resistance between low-level isoniazid resistant, high level isoniazid resistant and isoniazid sensitive MTB was compared. Results: A total of 11,274 isolates were included in the study. A statistically significant association (P < 0.001) was found between Ethionamide resistance and low-level isoniazid resistance (26.6%) as compared to high-level isoniazid resistance (8.85%) and isoniazid sensitivity (0.71%) in MTB strains. However this association was not seen in XDR-TB strains. Conclusion: Low level isoniazid resistance may be used as marker for phenotypic ethionamide resistance and hence guide clinicians' choice of antituberculous agent for MDR-TB in Pakistan. Further studies involving detection of genotypic association of isoniazid and ethionamide susceptibilities are needed before a final conclusion can be derived.http://www.ijmyco.org/article.asp?issn=2212-5531;year=2017;volume=6;issue=2;spage=167;epage=170;aulast=QamarEthionamideisoniazidMycobacterium tuberculosis |
| spellingShingle | Salima Qamar Joveria Q Farooqi Kausar Jabeen Rumina Hasan Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosis International Journal of Mycobacteriology Ethionamide isoniazid Mycobacterium tuberculosis |
| title | Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosis |
| title_full | Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosis |
| title_fullStr | Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosis |
| title_full_unstemmed | Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosis |
| title_short | Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosis |
| title_sort | phenotypic low level isoniazid resistance as a marker to predict ethionamide resistance in mycobacterium tuberculosis |
| topic | Ethionamide isoniazid Mycobacterium tuberculosis |
| url | http://www.ijmyco.org/article.asp?issn=2212-5531;year=2017;volume=6;issue=2;spage=167;epage=170;aulast=Qamar |
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