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BioMed Research International
Volume 2017, Article ID 4563826, 9 pages
Research Article

Prevalence and Molecular Characterization of Second-Line Drugs Resistance among Multidrug-Resistant Mycobacterium tuberculosis Isolates in Southwest of China

1Tuberculosis Reference Laboratory, Chongqing Tuberculosis Control Institute, Chongqing 400050, China
2Department of Pathogenic Organisms, Chongqing Medical University, Chongqing 400016, China
3Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China
4National Tuberculosis Reference Laboratory, National Center for TB Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
5Chongqing Hospital of Traditional Chinese Medicine, Chongqing 400021, China

Correspondence should be addressed to C. Yang; moc.361@minuhcgnay

Received 26 February 2017; Revised 28 May 2017; Accepted 18 June 2017; Published 17 July 2017

Academic Editor: Isabel Portugal

Copyright © 2017 Y. Hu 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.


This study aimed to investigate the prevalence of multidrug-resistant tuberculosis (MDR-TB) isolates resistant to the second-line antituberculosis drugs (SLDs) and its association with resistant-related gene mutations in Mycobacterium tuberculosis (M.tb) isolates from Southwest of China. There were 81 isolates resistant to at least one of the SLDs among 156 MDR-TB isolates (81/156, 51.9%). The rates of general resistance to each of the drugs were as follows: OFX (66/156, 42.3%), KAN (26/156, 16.7%), CAP (13/156, 8.3%), PTO (11/156, 7.1%), PAS (22/156, 14.1%), and AMK (20/156, 12.8%). Therefore, the most predominant pattern was resistant to OFX compared with other SLDs (). The results of sequencing showed that 80.2% OFX-resistant MDR-TB isolates contained gyrA mutation and 88.5% KAN-resistant isolates had rrs mutations with the most frequent mutation being A1401G. These results suggest that improper use of SLDs especially OFX is a real threat to effective MDR-TB treatment not only in China but also in the whole world. Furthermore the tuberculosis control agencies should carry out SLDs susceptibility testing and rapid screening in a broader population of TB patients immediately and the SLDs should be strictly regulated by the administration in order to maintain their efficacy to treat MDR-TB.