The impact of rapid detection of resistance with PCR has been poorly evaluated in low-endemic countries. In France, primary resistance to isoniazid and rifampicin were estimated at, respectively, 5.2%, and 1.2 %. Based on these estimates, French guidelines currently recommends to initiate a 4-drug containing regimen associating isoniazid (INH or H), rifampicin (RIFor RMP or R), pyrazinamide (PZA or Z) and ethambutol (EMB or E) pending the results of drug susceptibility testing (DST). The rationale behind routine use of EMB is to prevent the emergence of resistance to rifampicin (RMP), in case of primary resistance to INH. Hence, early detection of resistance to INH and RIF using molecular testing in Mycobacterium tuberculosis could allow early adaptation of antituberculosis treatment: i) start with a 3-drug containing regimen (i.e. INH, RIF, and PZA), in patients with fully susceptible isolates (currently 95% of cases); ii) early enforcement of treatment when resistance is suspected, pending in depth susceptibility testings. GenoType ®MTB DR plus sensitivity for RIF and INH resistance detection has been estimated at 100% and 83%, respectively.