Objective  To investigate the epidemiological characteristics of drug-resistance in pulmonary tuberculosis (TB) patients and the influencing factors in Tianjin in 2020.

  Methods  The pulmonary TB patients reported in Tianjin from January to December in 2020 were enrolled in this study and the sputum samples were collected from them for pathogen isolation and culture. The positive cultures were further identified to detect Mycobacterium tuberculosis. Drug susceptibility testing was used to detect the drug resistance of all the strains detected. The unconditional logistic regression analysis was performed to identify the influencing factors of drug-resistance in the pulmonary TB patients.

  Results  A total of 1314 pulmonary TB patients were enrolled and 1314 M. tuberculosis strains were isolated. Among these strains, 68.42% (899/1314) were pan-sensitive and 31.58% (415/1314) were drug-resistant. Of 415 drug-resistant strains, 10.05% (132/1314) were mono resistant, 4.11% (54/1314) were poly resistant, and 10.81% (142/1314) were multidrug resistant, and 6.61% (87/1314) had other patterns of drug resistance. The rate of isoniazid resistance was highest (19.79%), followed by the rate of streptomycin resistance (18.87%). The resistance rates to rifampin, levofloxacin and moxifloxacin were 11.87%, 13.13% and 13.38%, respectively. The resistance rates to kanamycin and amikacin were relatively low (0.91%, 0.75%). Among 156 rifampin resistant strains, the rate of pre-extensive drug-resistance (resistant to fluoroquinolone simultaneously) was 46.79% (73/156). The results of unconditional logistic regression analysis showed that, compared with the pan-sensitivity group, the proportion of the patients aged 40−59 years was higher in the mono resistance group and poly resistance/multidrug resistance group, while the proportion of the patients aged ≥60 years was lower (P<0.05). Compared with the pan-sensitivity group, the proportion of the re-treated patients was higher in the mono resistance group and poly resistance/multidrug resistance group (P<0.05). Compared with the mono resistance group, the proportion of the re-treated patients in the poly resistance/multidrug resistance group was higher (P<0.05). Age and treatment history were the influencing factors for mono resistance and poly resistance/multidrug resistance in the pulmonary TB patients (P<0.05). Compared with new patients, the rifampin resistance rate, multidrug resistance rate and pre-extensive drug resistance rate were significantly higher in the re-treated patients (P<0.001)

  Conclusion  The drug resistance was very serious in pulmonary TB patients in Tianjin in 2020. Being aged 40−59 years and treatment history were the influencing factors, especially for rifampin resistance.