Drug-resistant tuberculosis: Past, present, future

Chen Yuan Chiang, Rosella Centis, Giovanni Battista Migliori

Research output: Contribution to journalReview articlepeer-review

107 Citations (Scopus)


In a population of Mycobacterium tuberculosis, random chromosomal mutation that results in genetic resistance to anti-tuberculosis (TB) drugs occurs at a relatively low frequency. Anti-TB drugs impose selection pressure so that mycobacterial mutants gradually outnumber susceptible bacilli and emerge as the dominant strains. Resistance to two or more anti-TB drugs represents cumulative results of sequential mutation. The fourth report on global anti-TB drug resistance provides the latest data on the extent of such problem in the world. The median prevalence of multi-drug-resistant TB (MDR-TB) in new TB cases was 1.6%, and in previously treated TB cases 11.7%. Of the half a million MDR-TB cases estimated to have emerged in 2006, 50% were in China and India. The optimal duration of any given combination of anti-TB drugs for treatment of MDR- and extensively drug-resistant TB (XDR-TB) has not been defined in controlled clinical trials. Standardized treatment may be feasible for MDR-TB patients not previously treated with second-line drugs, but a different strategy needs to be applied in the treatment of MDR-TB patients who have received second-line drugs before. Unfortunately, the reliability of drug susceptibility testing of most second-line anti-TB drugs is still questionable. Drug-resistant TB is not necessarily less virulent. Findings from modelling exercise warned that if MDR-TB case detection and treatment rates increase to the World Health Organization target of 70%, without simultaneously increasing MDR-TB cure rates, XDR-TB prevalence could increase exponentially. Prevention of development of drug resistance must be accorded the top priority in the era of MDR-/XDR-TB.

Original languageEnglish
Pages (from-to)413-432
Number of pages20
Issue number3
Publication statusPublished - Apr 2010
Externally publishedYes


  • Extensively drug-resistant tuberculosis
  • Human immunodeficiency virus
  • Multi-drug-resistant tuberculosis
  • Review
  • Risk factor

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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