title: 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.
authors.affiliation: Department of Internal Medicine, Pusan National University Hospital, Busan, Korea.
authors.forename: Jeong Ha
authors.identifier: http://orcid.org/0000-0001-7406-1373
authors.initials: JH
authors.lastname: Mok
authors.affiliation: Department of Internal Medicine, Dong-A University Hospital, Busan, Korea.
authors.forename: Bo Hyoung
authors.identifier: http://orcid.org/0000-0001-5809-8360
authors.initials: BH
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, Ulsan University Hospital, Ulsan, Korea.
authors.forename: Taehoon
authors.identifier: http://orcid.org/0000-0002-9224-0866
authors.initials: T
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Inje University Busan Paik Hospital, Busan, Korea.
authors.forename: Hyun Kyung
authors.identifier: http://orcid.org/0000-0003-1032-0190
authors.initials: HK
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.
authors.forename: Hang Jea
authors.identifier: http://orcid.org/0000-0001-7733-4365
authors.initials: HJ
authors.lastname: Jang
authors.affiliation: Department of Internal Medicine, Gyeongsang National University Hospital, Jinju, Korea.
authors.forename: Yu Ji
authors.identifier: http://orcid.org/0000-0002-0247-802X
authors.initials: YJ
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea. sooli10kr@yahoo.co.kr.|Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea.
authors.forename: Doosoo
authors.identifier: http://orcid.org/0000-0002-8206-9487
authors.initials: D
authors.lastname: Jeon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000302:isolation & purification; D011718:Pyrazinamide / Q000627:therapeutic use; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D062606:Tertiary Care Centers; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents; D024841:Fluoroquinolones; D011718:Pyrazinamide
keywords: Drug Resistance; Extensively Drug-Resistant Tuberculosis; Korea; Tuberculosis; Tuberculosis, Multidrug-Resistant