Dynamic characteristics of drug resistant tuberculosis in Leiyang, Hunan, 2013–2017

ObjectiveTo analyze the dynamic trend of drug resistance of Mycobacterium tuberculosis in Leiyang city, Hunan province from 2013 to 2017, and to understand the local drug resistance spectrum of M. tuberculosis, so as to provide evidences for the formulation of chemotherapy regimen of tuberculosis (TB) and TB prevention and control.

MethodsThe strains of M. tuberculosis collected in Leiyang from 2013 to 2017 were analyzed retrospectively. After identification by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), all the M. tuberculosis strains were subjected to susceptibility tests of 8 first and second line anti-TB drugs by using microtiter plate method to understand the minimum inhibitory concentration. Statistical description and Chi-square for trend test were used to analyze the drug resistance trend.

ResultsA total of 568 clinical strains of M. tuberculosis were included in this study, of which 18.49% (105/568) were from retreated TB cases, and 81.51% (463/568) form new TB cases. Overall, the drug resistance rate was 22.13% (120/568), the multi-drug resistance rate was 6.34% (36/568) and the extensively drug resistance rate was 0.35% (2/568). Drug resistance trend analysis showed that only the resistance rate to fluoroquinolones increased year by year (trend χ²＝8.585, P＝0.003), while the fluctuations of the drug resistance rate to other drugs, overall drug resistance rate and multi-drug resistance rate were not obvious, the differences were not statistically significant.

ConclusionOverall, the drug resistance of tuberculosis in Leiyang was serious, the resistance rate to fluoroquinolones showed an increasing trend, and close attention should be paid on that. The standardized use of fluoroquinolones should be strengthened. Cross-drug resistance should be fully considered in the treatment of patients with drug resistant TB. In addition, the management of MDR-TB patients should be strengthened to reduce the incidence of primary drug resistant TB.