Résumé
【Objective】 To understand the epidemic status of drug-resistant Mycobacteriun tuberculosis in Xi’an in the past three years, and the impact of COVID-19 epidemic during 2020 so as to provide basic information for local multidrug-resistant tuberculosis (MDR-TB) prevention and treatment. 【Methods】 Tuberculosis (TB) detected by sputum culture, the corresponding drug susceptibility tests data, and basic clinical information of TB patients diagnosed in Xi’an from January 2018 to October 2020 were collected from the management system; then the epidemic status and the drug resistance status were analyzed. Multinomial logistic regression was used to analyze the relationship between the patients’ treatment history and the drug resistance of TB strains, and the trend of changes in the drug resistance rate in retreated patients. 【Results】 In the past three years, there was a total drug resistance rate of 25.3% in 5 146 strains of MTB, and 24.8% in treatment initiation and 38.22% in retreatment, respectively. The treatment initiation patients showed a decreased MDR-TB detection rate, and the retreated patients had an increased MDR-TB detection rate. The spectrum of MDR-TB in the retreated patients gradually became more complicated, and the resistance rate of second-line drugs such as Kanamycin and Ofloxacin gradually increased. There were 10 drug-resistant combinations mainly in H+R+S and H+R+S+E. During the year 2020 of COVID-19 epidemic, the number of initial and retreated patients decreased significantly compared with that in 2018 and 2019, but with no difference in the drug-resistance rate. There was an increasing detection rate of PDR and MDR-TB strains in the retreated patients. Multinomial logistic regression results showed that in 2020 the retreated patients had 4.28 times of developing PDR-TB (P=0.001, 95% CI=1.417-12.930), and 5.378 times of developing MDR-TB (P<0.001, 95% CI=2.641-10.952) than patients of treatment initiation. 【Conclusion】 In the past three years, the prevention and control of drug-resistant TB in Xi’an has achieved some progress, but drug resistance in retreated patients is still serious. To avoid and reduce the development of drug-resistant TB, precise and active intervention measures should be taken, and health management of TB patients should be strengthened, especially during the current period of COVID-19 epidemic prevention and control.
Résumé
Objective To assess the antimicrobial resistance and resistance-related mutations in rpoB and katG genes in Mycobacteria tuberculosis isolates from patients with cutaneous tuberculosis. Methods Seven strains of Mycobacteria were isolated from lesions or secretions of patients with cutaneous tuberculosis and identified as M. tuberculosis. Proportion method was used to test the susceptibility of M. tuberculosis isolates to rifampicin, isoniazid, streptomycin and ethambutol. PCR and sequencing were performed to analyze the mutations in rpoB and katG genes. Results Of the 7 isolates of M. tuberculosis, 1 was resistant to rifampicin,isoniazid and ethambutol simultaneously, and the other 6 were sensitive to rifampicin, isoniazid, streptomycin and ethambutol. All the 7 isolates were positive for the amplification of rpoB and katG genes by PCR. DNA sequencing revealed two mutations at codon 531 (TCG to TTG) and codon 315 (AGC to ACC) in the multi-drug resistant strain, which were absent in the other 6 strains. Conclusion Multi-drug resistance has emerged in M. tuberculosis isolates from patients with cutaneous tuberculosis, which is likely to be related to improper treatment.