Additional Drug Resistance Patterns among Multidrug-Resistant Tuberculosis Patients in Korea: Implications for Regimen Design

Abstract

Detailed information on additional drug resistance patterns of multidrug-resistant tuberculosis (MDR-TB) is essential to build an effective treatment regimen; however, such data are scarce in Korea. We retrospectively analyzed the results of phenotypic drug susceptibility testing (DST) of culture confirmed-TB patients from January 2010 to December 2014 in 7 university hospitals in Korea. MDR-TB was identified among 6.8% (n = 378) of 5,599 isolates. A total of 57.1% (n = 216) of the MDR-TB patients had never been treated for TB. Strains from MDR-TB patients showed additional resistance to pyrazinamide (PZA) (35.7%), any second-line injectable drug (19.3%), and any fluoroquinolone (26.2%). Extensively drug resistant TB comprised 12.4% (n = 47) of the MDR-TB patients. Of 378 MDR-TB patients, 50.3% (n = 190) were eligible for the shorter MDR-TB regimen, and 50.0% (n = 189) were fully susceptible to the 5 drugs comprising the standard conventional regimen (PZA, kanamycin, ofloxoacin, prothionamide, and cycloserine). In conclusion, the proportion of new patients and the levels of additional drug resistance were high in MDR-TB patients. Considering the high levels of drug resistance, the shorter MDR-TB treatment regimen may not be feasible; instead, an individually tailored regimen based on the results of molecular and phenotypic DST may be more appropriate in MDR-TB patients in Korea.

Delamanid, linezolid, levofloxacin, and pyrazinamide for the treatment of patients with fluoroquinolone-sensitive multidrug-resistant tuberculosis (Treatment Shortening of MDR-TB Using Existing and New Drugs, MDR-END): study protocol for a phase II/III, multicenter, randomized, open-label clinical trial

“…In European MDR-TB cohorts, on average, only 7.8% were eligible for this shortened regimen [20]. Reports from other areas, including Singapore, Brazil, Pakistan, and South Korea, assume eligibility for the shorter regimen ranged from 30 to 55% [21–24].…”

Epidemiologia global de pacientes com tuberculose multidrogarresistente (MDR-TB) e extensivamente resistente (XDR-TB)

“…A XDR-TB foi encontrada em 12,4% dos indivíduos. Os altos níveis de resistência encontrados denotam o grande desafio de construir esquemas terapêuticos de sucesso 36 .…”

WHO Treatment Guidelines for Drug-Resistant Tuberculosis, 2016 Update: Applicability in South Korea

“…Additional resistance to pyrazinamide, ofloxacin, and kanamycin was 26.2%–59%, 16.6%–47.5%, and 13.3%–25%, respectively 3 8 9 10 11 . A recent regional survey of drug resistance in South Korea demonstrated that strains from MDR-TB patients had additional resistance to pyrazinamide (35.7%), fluoroquinolones (26.2%), and second-line injectable drugs (19.3%) 53 . Rapid DSTs detecting fluoroquinolone and injectable drug resistance, such as MTBDRsl test, is a prerequisite for identifying patients with MDR-TB eligible for the shorter treatment regimen.…”