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Malawi Medical Journal
College of Medicine, University of Malawi and Medical Association of Malawi
ISSN: 1995-7262
Vol. 30, No. 1, 2018, pp. 1-5
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Bioline Code: mm18001
Full paper language: English
Document type: Research Article
Document available free of charge
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Malawi Medical Journal, Vol. 30, No. 1, 2018, pp. 1-5
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The occurrence and frequency of genomic mutations that mediate Isoniazid and Rifampicin resistance in Mycobacterium tuberculosis isolates from untreated pulmonary Tuberculosis cases in urban Blantyre, Malawi
Kumwenda, Geoffrey P; Chipungu, Geoffrey; Sloan, Derek J; Kaimila, Yankho; Chiumya, Kondwani & Pangani, Harry
Abstract
Background The emergence and spread of drug-resistant Tuberculosis (TB) is a major public health threat. TB resistance originates in the course
of treatment due to genomic mutations in Mycobacterium tuberculosis (MTB). An increase in new cases with drug-resistant TB could be
an indicator of high levels of circulating resistant strains. This study was conducted to determine the occurrence and frequency of
genomic mutations that mediate Isoniazid (INH) and Rifampicin (RIF) resistance among isolates from untreated TB cases in urban
Blantyre, Malawi.
Methods A cross-sectional retrospective study was conducted on a panel of 141(n=141) MTB clinical isolates recovered between June 2010
and January 2012 from ≥ 2+ Ziehl-Neelsen smear positive new pulmonary-TB patients with no history of treatment. Frozen isolates
were revived using the BACTEC MGIT detection system. DNA was extracted using GenoLyse DNA extraction kit and detection of
genomic mutations was carried out using the GenoType MTBDRplus Ver 2.0 assay.
Results Out of the 141 isolates studied, 3 (2.1%) were found carrying mutations in the katG gene that confer resistance to Isoniazid (INH). No
mutations were detected in the inhA promoter region gene that confer weak INH resistance or in the rpoB gene that confer Rifampicin
resistance. All katG mutant genes had a S315T1 single point mutation, a genomic alteration that mediates high INH resistance.
Conclusion
The katG mutant gene conferring resistance to INH was the only genomic mutation observed among the isolates studied and the
frequency of occurrence was low. Our findings suggest low levels of circulating drug-resistant MTB strains in urban Blantyre, Malawi.
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© Copyright 2018 - The College of Medicine and the Medical Association of Malawi Alternative site location: http://revista.uft.edu.br/index.php/jbb/index
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