To explore the reliability of Xpert MTB/RIF (Xpert) in the diagnosis of pulmonary tuberculosis and to understand the characteristics of retreated patients, so as to provide clues for the investigation of retreated patients.

905 patients sputum with suspected tuberculosis from July 2019 to December 2019 were collected from the Tuberculosis Department of Changsha Central Hospital. Xpert was used for rapid screening of tuberculosis. MGIT960 and Roche culture method were used for rapid sputum culture and drug sensitivity, respectively. Rifampin (RIF) resistance was compared between Xpert and Roche culture. The gender, age, RIF resistance, occupation and diabetes mellitus of patients with positive Xpert were compared, and the risk factors of RIF resistance were analyzed by binary logistic regression.

The total detection rate of Xpert was 28.7%(260/905) in 905 suspected pulmonary tuberculosis patients; RIF resistance rate accounted for 20.8%(54/260) in 260 positive patients, and the main mutation types were probe-E and probe-D. There was no significant difference between traditional drug sensitivity and Xpert method in RIF resistance detection (P>0.05); There was no significant difference between Xpert method and traditional drug sensitive cases in predicting isoniazid (INH) resistance (P=0.293); there were significant differences in age (t=-3.835, P<0.05), gender, RIF resistance rate and proportion of farmers between newly treated and retreated patients (χ²=5.091, 16.862, 4.808, P<0.05); Binary logistic regression showed that retreatment was a risk factor for RIF resistance (OR=3.739, P=0.004).

Xpert has high clinical value in the diagnosis of pulmonary tuberculosis and RIF resistance; The retreated patients were older, and the proportion of male farmers was larger, with higher resistance rate to RIF.

Tuberculosis, pulmonary; Molecular diagnostic techniques; Drug resistance, bacterial; Rifampin; Mycobacterium tuberculosis