Identification moléculaire des mycobactéries non tuberculeuses

The molecular biology techniques allowed important progress in the detection and the identification of non-tuberculous mycobacteria. The detection of certain species such as Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium kansasii and Mycobacterium malmoense can be performed by nucleic acid amplification directly from the sample, by using a technique for which the sensitivity and the specificity were respectively estimated at 92 % and 100 %. Now, the identification of non-tuberculous mycobacteria from the cultures is based on molecular biology techniques, which can be classified in three groups. I) Monospecific probes, based on DNA hybridization, are a sensitive, fast and simple method, but the commercial assays available are only able to identify five species of mycobacteria. II) Techniques requiring amplification followed by a hybridization step on a solid support are more complex than probes, but are able to identify 16 to 28 species of mycobacteria. III) Systems based on sequencing or enzymatic restriction are implemented in reference laboratories.