[Resistant tuberculosis: a molecular review].

Progress to understanding the basis of resistance to antituberculous drugs has allowed molecular tests for detection of drug-resistant tuberculosis to be developed. Drug-resistant tuberculosis poses a threat to tuberculosis control programs. It is necessary thus to know drug susceptibilities of individual patient's strain to provide the appropriate drug combinations. Molecular studies on the mechanism of action of antituberculous drugs have elucidated the genetic basis of drug resistance in M. tuberculosis. The mechanisms of drug resistance in tuberculosis are a result of chromosomal mutations in different genes of the bacteria. Upon drug exposure there is a selective pressure for such resistant mutants. Multidrug-resistant tuberculosis is a health problem of increasing significance for the whole global community. This paper reviews the molecular mechanisms associated with drug-resistance as well the new perspectives for detecting resistant isolates.