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BioMed Research International
Volume 2015 (2015), Article ID 951706, 8 pages
http://dx.doi.org/10.1155/2015/951706
Research Article

Mutations Found in embCAB, embR, and ubiA Genes of Ethambutol-Sensitive and -Resistant Mycobacterium tuberculosis Clinical Isolates from China

1Molecular Laboratory, Beijing Chest Hospital, Capital Medical University, 97 Machang Road, Tongzhou District, Beijing 101149, China
2Beijing Key Laboratory for Drug Resistance Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, 97 Machang Road, Tongzhou District, Beijing 101149, China
3National Tuberculosis Clinical Laboratory, Beijing Chest Hospital, Capital Medical University, 97 Machang Road, Tongzhou District, Beijing 101149, China

Received 8 June 2015; Revised 7 August 2015; Accepted 19 August 2015

Academic Editor: Sherry L. Mowbray

Copyright © 2015 Yuhui Xu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

To better understand the molecular mechanisms of Ethambutol (EMB) resistance, the mutant hot spot region of five genes (embB, embA, embC, embR, and ubiA) was amplified and sequenced in 109 EMB-resistant and 153 EMB-susceptible clinical isolates from China. Twenty-seven EMB-susceptible isolates were found to have nonsynonym mutations, 23 of which were in embB. The mutations occurred most frequently in embB (85.3%, 93) and were seldom in embC (2.8%, 3), embA (3.7%, 4), embR (3.7%, 4), and ubiA (8.3%, 9) in EMB-resistant isolates. For the embB gene, 63 isolates showed mutations at embB306, 20 at embB406, nine at embB497, and five at embB354 in EMB-resistant isolates. In addition, the particular mutants at embB406 and embB497 indicated both high levels of EMB resistance (μg/mL) and broad anti-TB drug resistance spectrums. Our data supported the facts that embB306 could be used as a marker for EMB resistance with a sensitivity of 57.8% and a specificity of 78.8%.