Trend of multidrug and fluoroquinolone resistance in Mycobacterium tuberculosis isolates from 2010 to 2014 in Korea: a multicenter study

BACKGROUND/AIMS:This study was conducted to evaluate the recent prevalence and trend of anti-tuberculosis (TB) drug resistance with a focus on multidrug-resistance (MDR) and fluoroquinolone resistance in South Korea. METHODS:We retrospectively reviewed the drug susceptibility testing results of culture-confirmed Mycobacterium tuberculosis isolates collected from 2010 to 2014 at seven tertiary hospitals in South Korea. RESULTS:A total of 5,599 cases were included: 4,927 (88.0%) were new cases and 672 (12.0%) were previously treated cases. The MDR rate has significantly decreased from 6.0% in 2010 to 3.0% in 2014 among new cases, and from 28.6% in 2010 to 18.4% in 2014 among previously treated cases (p < 0.001 and p = 0.027, respectively). The resistance rate to any f luoroquinolone was 0.8% (43/5,221) in non-MDR-TB patients, as compared to 26.2% (99/378) in MDR-TB patients (p < 0.001). There was no significant change in the trend of fluoroquinolone resistance among both nonMDR-TB and MDR-TB patients. Among the 43 non-MDR-TB patients with fluoroquinolone resistance, 38 (88.4%) had fluoroquinolone mono-resistant isolates. CONCLUSION:The prevalence of MDR-TB has significantly decreased from 2010 to 2014. The prevalence of fluoroquinolone resistance among non-MDR-TB patients was low, but the existence of fluoroquinolone mono-resistant TB may be a warning on the widespread use of fluoroquinolone in the community.