Drug resistance rate of Mycobacterium tuberculosis and risk factors in western China, 2016–2018

  Objective  To understand the drug resistance of Mycobacterium tuberculosis in western China from 2016 to 2018, analyze the risk factors for drug-resistance pulmonary tuberculosis (TB), and provide the scientific evidences for TB prevention and control.

  Methods  A total of 843 smear-positive pulmonary TB cases reported in 6 TB drug resistance areas in western China, i.e. Fengdu and Fengjie counties of Chongqing, Weiyang district of Shaanxi, Tonghai county of Yunnan, Golmud city of Qinghai and Haiyuan county of Ningxia during 2016–2018 were studied. The biochemical identification and drug susceptibility test with proportional method of all the M. tuberculosis strains isolated from these cases were conducted. An unified questionnaire was used to collect the information about cases’ demographic characteristics and disease type.Univariate analysis (χ² test) and multivariate analysis (Logistic regression analysis) were conducted to identify the risk factors associated with drug resistance of TB.

  Result  The overall drug resistance rate and multidrug resistance rate of the 843 M. tuberculosisstrains to six anti-TB drugs were 23.13% and 6.17%,respectively. The drug resistance rate to streptomycin was highest (13.29%), followed by isoniazide (13.05%), rifampicin (9.37%), ofloxacin (5.69%), ethambutol (4.39%), and , kanamycin (1.42%). The differences in overall drug resistance rate among different year (22.41% in 2016, 26.69% in 2017, 20.59% in 2018) were not significant. Among 6 surveillance areas in west China, the single drug resistance rates to isoniazide, rifampicin, streptomycin and ofloxacin was highest in Weiyang district of Shaanxi, which were 22.29%, 20.57%, 23.43% and 12.00%, respectively, the resistance rate to ethambutol rate in Golmud city of Qinghai was highest (10.91%), the resistance rate to kanamycin in Tonghai county of Yunnan was highest (5.66%). the differences were all significant. The univariate analysis indicated that disease of type ( χ²=7.736, P=0.005), gender ( χ²=4.149, P=0.042), residence ( χ²=9.112, P=0.03), level of education ( χ²=15.182, P=0.004) were the factors associated with TB drug resistance.Multivariate analysis indicated that gender, retreatment, and drug surveillance point were the risk factors associated with TB drug resistance.

  Conclusion  The TB drug resistance was relatively severe in west China, especially in Weiyang district of Shaanxi. It is necessary to strengthen the TB drug resistance surveillance and promote rational use of anti-TB drugs for the prevention and control of drug-resistant TB.