title: Multidrug-resistant and extensively drug-resistant tuberculosis: a review.
abstract: OBJECTIVE
  The spread of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant TB (XDR-TB) is a major medical and public health concern for the world. These two forms of highly drug-resistant TB threaten to make TB into an untreatable and highly fatal disease, particularly in resource-poor countries with a high prevalence of AIDS. The focus of this review is to highlight the current extent of the problem.
  
  
  RESULTS
  There is a great variability in clinical outcomes for MDR-TB, in part due to differences in the definitions of outcome measures and retrospective nature of the studies. Outcomes for XDR-TB are uniformly worse than those for MDR-TB.
  
  
  CONCLUSIONS
  A multifaceted approach is needed to prevent a more widespread epidemic of MDR-TB and XDR-TB. Rapid diagnostic assays to detect highly drug-resistant TB are essential in preventing delays in treatment of MDR-TB and XDR-TB and curbing their spread. Development of new drugs to effectively treat all forms of TB in a shorter period of time is urgently needed.
authors.affiliation: Department of Medicine, National Jewish Medical and Research Center, Denver, CO 80206, USA.
authors.forename: Edward D
authors.initials: ED
authors.lastname: Chan
authors.forename: Michael D
authors.initials: MD
authors.lastname: Iseman
mesh_terms: D000995:Antitubercular Agents / Q000627:therapeutic use; D003140:Communicable Disease Control / Q000379:methods; D054908:Extensively Drug-Resistant Tuberculosis / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control; D005798:Genes, Bacterial; D006801:Humans; D012307:Risk Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000517:prevention & control
chemical_list: D000995:Antitubercular Agents