Abstract:

Objective To investigate the role of Xpert MTB/RIF system in the rapid detection of Mycobacterium tuberculosis（MTB） and rifampicin resistance. Methods The sputum samples of 1 562 suspected tuberculosis patients were collected,and were determined by Xpert MTB/RIF,liquid culture and acid resistance staining method. The sensitivity and specificity of Xpert MTB/RIF for detecting acid resistance staining positive samples were analyzed using liquid culture method as the standard. The identification and the drug susceptibility test were carried out on 188 cases of positive liquid culture samples to evaluate the sensitivity and specificity of the detection of MTB and rifampicin resistance by Xpert MTB/RIF. Results The consistency rate of Xpert MTB/RIF with liquid culture was 93.92%（χ²=3.55,P>0.05）. That with smear method was 89.44 %（χ²=48.51,P<0.001）. The sensitivity of Xpert MTB/RIF was 82.41%（328/398）,and the specificity was 97.85%（1 139/1 164）,using liquid culture as a standard,with no statistical significance between Xpert MTB/RIF and liquid culture（χ²=3.55,P>0.05）. Totally,188 positive liquid culture samples were confirmed by final identification,the sensitivity of Xpert MTB/RIF was 91.23%（156/171）,the specificity was 88.24%（15/17）,the accuracy was 90.96%（171/188）,and there was no statistical significance between Xpert MTB/RIF and liquid culture（χ²=4.109,P>0.05）. The sensitivity of Xpert MTB/RIF to rifampicin resistance was 82.35%（14/17）,the specificity was 99.35%（1/154）,and there was no statistical significance between Xpert MTB/RIF and traditional proportional method（χ²=0.138,P>0.05）. Conclusions The Xpert MTB/RIF system could detect MTB and rifampicin resistance rapidly,with high sensitivity and specificity,and it is potential in the clinical application.

Key words: Mycobacterium tuberculosis, Xpert MTB/RIF system, Rifampicin, Drug resistance