Analysis of phenotypic drug sensitivity of rifampicin-resistant Mycobacterium tuberculosis detected by Xpert MTB/RIF
MIAO Xingguo1, 2, YE Hui1, 2, CHEN Xianhao1, 2, HUANG Mohe1, 2, SU Feifei1, 2.
1.Department of Infectious Diseases, Wenzhou Central Hospital, Dingli Clinical College of Wenzhou Medical University, Wenzhou 325000, China; 2.Department of Infection and Immunity, the Sixth People’s Hospital of Wenzhou,Wenzhou 325000, China
MIAO Xingguo,YE Hui,CHEN Xianhao, et al. Analysis of phenotypic drug sensitivity of rifampicin-resistant Mycobacterium tuberculosis detected by Xpert MTB/RIF[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2022, 52(11): 899-902,908.
Abstract：Objective: To analyze the results of the phenotypic drug sensitivity test of rifampicin-resistant tuberculosis patients diagnosed by Xpert MTB/RIF (Xpert) assay to provide a scientific basis for the treatment of drug-resistant tuberculosis. Methods: Tuberculosis patients who were treated in the Infection Department of Wenzhou Central Hospital between January 2015 and December 2020 and showed rifampicin resistance in sputum or alveolar lavage fluid Xpert test were selected, and the results of phenotypic drug sensitivity of Mycobacterium tuberculosis were retrospectively analyzed. Results: The result of the first-line anti-tuberculosis drug susceptibility test was obtained from 570 rifampicin-resistant pulmonary tuberculosis diagnosed by Xpert,and the order of the drug resistance rate was rifampicin (90.18%) > isoniazid (88.60%) > streptomycin (56.32%)> ethambutol (29.47%); the resistance rates to isoniazid, rifampicin, and ethambutol in re-treated patients
(94.50%, 94.50%, and 35.78%, respectively) were significantly higher than those in the new patients (84.94%,87.50%, and 25.57%, respectively). There were 24 strains sensitive to first-line anti-tuberculosis drugs, and 46,156, 226 and 118 strains resistant to 1, 2, 3, and 4 drugs, respectively. There were 476 patients (278 new patients
and 198 re-treated patients) diagnosed with multidrug-resistant tuberculosis (MDR-TB), with the proportion of MDR-TB significantly higher in re-treated patients that in the new patients (90.83% vs. 78.98%, χ2=13.723,P<0.001). The results of second-line antituberculosis drug sensitivity test obtained from 302 patients showed
the order of resistance rate was ofloxacin (35.76%) = amikacin (35.76%) > kanamycin > kanamycin (13.25%) =capreomycin (13.25%), with the resistance rate to ofloxacin in new patients significantly lower than in re-treated patients (26.46% vs. 51.33%, χ2=19.044, P<0.05); 128 strains were fully susceptible to second-line antituberculosis drugs, and 111, 23, 21 and 19 strains were resistant to 1, 2, 3 and 4 drugs, respectively. There were 50 patients (25 new patients and 25 re-treated patients) diagnosed with extensively drug-resistant tuberculosis (XDR-TB), with a higher proportion of re-treated patients with XDR-TB (22.12% vs. 13.23%, χ2=4.051, P=0.044). Conclusion:Resistance to isoniazid, ofloxacin, and amikacin is common in rifampicin-resistant patients diagnosed by Xpert. Re-treated patients have more severe drug-resistance than new patients. The drug sensitivity results for first- and second-line anti-tuberculosis drugs should be obtained as early as possible to guide clinical use.
