Methods for determining the antimicrobial susceptibility of mycobacteria

Mycobacteria are a large group of microorganisms, multiple species of which are major causes of morbidity and mortality, such as tuberculosis and leprosy. At present, the emergence and spread of multidrug-resistant strains of Mycobacterium tuberculosis complex are one of the most serious health problems worldwide. Furthermore, in contrast to M. tuberculosis and Mycobacterium leprae, non-tuberculous mycobacteria (NTM) are more frequently isolated and, in many cases, treatment is based on drug susceptibility testing. This article is a review of the different methods to determine the in vitro drug susceptibility of M. tuberculosis complex and the most relevant NTM isolates. The molecular techniques currently used for rapid detection of resistance of clinical specimens are also analysed.