[Tuberculosis in 2015: From diagnosis to the detection of multiresistant cases]

Incidence of pulmonary tuberculosis, a contagious infectious disease, decreases in France with 4934 reported cases in 2013. Tuberculosis remains a global health problem as smear is positive in only 50% cases and culture methods require time. In such a context, genotypic diagnostic tools such as Xpert® MTB/RIF gained interest. This rapid and simple-to-use nucleic acid amplification test allows a diagnosis in two hours and prevents further invasive investigations in pulmonary and mediastinal tuberculosis. Because of its low sensitivity, it cannot be used in pleural fluid. Indirect immunologic tests are of no use to diagnose active tuberculosis disease. Another current area of interest is the emergence of resistant tuberculosis. In France, approximately 100 cases of multidrug resistant tuberculosis and a few extensively drug resistant tuberculosis have been reported in 2014. Even though these forms of tuberculosis are imported, it is crucial to identify hazardous situations and to optimize care of these patients. Xpert® MTB/RIF is again of marked interest here as it detects rifampin resistance with a 95% sensitivity and a 98% specificity. Interpretation of genotypic tests such as Genotype® MTBDR or Xpert® MTB/RIF depends on known detected mutations, although they do not always have a clinical or phenotypic expression. In multidrug resistant tuberculosis, the new drug bedaquiline obtained approval for temporarily use in combination with other molecules when there is no other treatment option. Results of bedaquiline are encouraging but adverse events like QT prolongation or the development of new specific drug resistance should convince clinicians to use it with caution.