title: Acquired Drug Resistance in Mycobacterium tuberculosis and Poor Outcomes among Patients with Multidrug-Resistant Tuberculosis.
abstract: Rates and risk factors for acquired drug resistance and association with outcomes among patients with multidrug-resistant tuberculosis (MDR TB) are not well defined. In an MDR TB cohort from the country of Georgia, drug susceptibility testing for second-line drugs (SLDs) was performed at baseline and every third month. Acquired resistance was defined as any SLD whose status changed from susceptible at baseline to resistant at follow-up. Among 141 patients, acquired resistance in Mycobacterium tuberculosis was observed in 19 (14%); prevalence was 9.1% for ofloxacin and 9.8% for capreomycin or kanamycin. Baseline cavitary disease and resistance to >6 drugs were associated with acquired resistance. Patients with M. tuberculosis that had acquired resistance were at significantly increased risk for poor treatment outcome compared with patients without these isolates (89% vs. 36%; p<0.01). Acquired resistance occurs commonly among patients with MDR TB and impedes successful treatment outcomes.
authors.forename: Russell R
authors.initials: RR
authors.lastname: Kempker
authors.forename: Maia
authors.initials: M
authors.lastname: Kipiani
authors.forename: Veriko
authors.initials: V
authors.lastname: Mirtskhulava
authors.forename: Nestani
authors.initials: N
authors.lastname: Tukvadze
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Magee
authors.forename: Henry M
authors.initials: HM
authors.lastname: Blumberg
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000494:pharmacology / Q000627:therapeutic use; D060085:Coinfection; D015897:Comorbidity; D024901:Drug Resistance, Multiple, Bacterial; D054908:Extensively Drug-Resistant Tuberculosis / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000302:isolation & purification; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents
keywords: MDR TB; Mycobacterium tuberculosis; XDR TB; acquired drug resistance; antimicrobial resistance; bacteria; extensively drug-resistant tuberculosis; multidrug resistance; multidrug-resistant tuberculosis; treatment outcomes; tuberculosis and other mycobacteria