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Open Access Research article

Rapid and accurate detection of RMP- and INH- resistant Mycobacterium tuberculosis in spinal tuberculosis specimens by CapitalBio™ DNA microarray: A prospective validation study

Zehua Zhang1, Litao Li2, Fei Luo1, Peng Cheng1, Feng Wu3, Zheng Wu1, Tianyong Hou1, Min Zhong4 and Jianzhong Xu1*

  • * Corresponding author: Jianzhong Xu xjzslw@163.com

  • † Equal contributors

Author Affiliations

1 Department of Orthopaedics, Southwest Hospital, Third Military Medical University, Chongqing, China

2 Department of Orthopaedics, The 309th Hospital of PLA, Beijing, China

3 Institution of Pathology, Southwest Hospital, Third Military Medical University, Chongqing, China

4 Department of Clinical Laboratory, Infectious Disease Medical Center, Chongqing, China

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BMC Infectious Diseases 2012, 12:303  doi:10.1186/1471-2334-12-303

Published: 14 November 2012

Abstract

Background

DNA microarrays can detect tuberculosis and its multi-drug resistant form in M. tuberculosis isolates and sputum specimens with high sensitivity and specificity. However, no performance data currently exists for its use in spinal tuberculosis specimens. This study was aimed to assess the performance of the CapitalBio™ DNA microarray in the detection of isoniazid (INH) and rifampicin (RMP) resistance in spinal tuberculosis compared with the BACT/MGIT 960 system.

Methods

From March 2009 to December 2011, 153 consecutive patients from Southwest Hospital, Chongqing with clinically and pathologically diagnosed spinal tuberculosis were enrolled into this study. Specimens collected during surgery from the tuberculosis patients were subjected to M. tuberculosis species identification and drug-resistance detection by the CapitalBio™ DNA microarray, and results were compared with those obtained from the absolute concentration drug susceptibility testing.

Results

The CapitalBio™ DNA microarray achieved 93.55% sensitivity for the correct M. tuberculosis species identification of the 93 specimens that tested positive for spinal tuberculosis through culture. In addition, twenty-seven additional patients (45.0%) were detected by the DNA microarray to be positive for M. tuberculosis among sixty spinal tuberculosis patients who were culture negative. Moreover, the DNA microarray had a sensitivity of 88.9% and a specificity of 90.7% for RMP resistance, and the microarray had a sensitivity of 80.0% and a specificity of 91.0% for INH resistance. The mean turn-around time of M. tuberculosis species identification and drug resistance detection using the DNA microarray was 5.8 (range, 4–9) hours.

Conclusions

The CapitalBio™ DNA microarray is a feasible and accurate tool for the species identification of M. tuberculosis and for directly detecting RMP and INH resistance from spinal tuberculosis specimens in fewer than 9 hours.

Keywords:
DNA microarray; Spinal tuberculosis; Drug resistance; Gene mutation