The continued rise in the incidence of antibiotic-resistant bacterial strains in French healthcare facilities represents a serious public health problem. Controlling the spread of multidrug-resistant bacteria (MDRB) has become a priority for organizations combating healthcare-associated infections at the national level. The objectives of this study were to provide an interregional overview and to evaluate the impact of prevention measures on controlling the spread of MRBs in healthcare facilities in the southwestern interregional area (Aquitaine, Guadeloupe, French Guiana, Limousin, Martinique, Midi-Pyrénées, Poitou-Charentes). (R.A.)