Purpose: Multidrug-resistant tuberculosis (MDR-TB) is the cause of serious health and economic burdens worldwide. The present study aimed to explore the initial and acquired drug-resistance rates among TB patients from 2012 to 2019 in Dalian, China. The effectiveness of MDR-TB prevention and control strategies were then evaluated.
Patients and Methods: Drug susceptibility testing (DST) was performed for 6429 diagnosed, culture-positive, Mycobacterium tuberculosis  (MTB) strains, including 4661 new cases and 1768 previously treated cases. Descriptive statistics were employed to calculate the frequencies and percentages of TB strains, and the average annual growth rates (AAGRs) for each strain were calculated. The Chi-square test was applied to examine the significance of linear drug-resistance trends over time during the study period.
Results: Over the eight-year study period, the percentages of both initial (from 9.01% to 4.82%) and acquired (from 40.85% to 9.09%) MDR-TB cases decreased significantly, AAGRs of 8.55% and 19.32%, respectively. Among new and previously treated TB patients, significant downtrends were observed for the rates of both initial and acquired MDR-TB among young and middle-aged individuals (P < 0.05). Additionally, among both new and previously treated TB patients, the percentages of individuals with drug resistance against isoniazid (INH), rifampicin (RFP), ofloxacin (OFX), and amikacin (AMK) decreased significantly (P < 0.05) from 2012 to 2019 in Dalian, China.
Conclusion: The initial and acquired multidrug resistance rates exhibited significantly decreasing trends from 2012 to 2019, suggesting that MDR-TB prevalence has been controlled effectively in Dalian, China. The MDR-TB epidemic was reversed in the short term by establishing feasible strategies for detection, diagnosis, treatment, and infection control.
Keywords: TB, initial, acquired, MDR, epidemic