[Risk factors and treatment of methicillin-resistant Staphylococcus aureus infections].

METICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS INFECTIONS (MRSA): The maintenance of a catheter in febrile neutropenic patients with MRSA bacteremia is justified, except when the latter persists 2 to 3 days after the initiation of treatment. Prior administration of fluoroquinolones (levofloxacine or ciprofloxacine) is a risk factor significantly associated with the isolation of MRSA. Meticillin resistance is not a factor of mortality in HIV-infected patients exhibiting S. aureus bacteremia. Surveillance blood cultures represent a simple method for identifying patients at high risk of secondary foci. INFECTIONS WITH GLYCOPEPTIDE-INTERMEDIATE MRSA (HETERO-GISA): In liver transplant recipients, the risk of acquiring a hetero-GISA is not associated with prior MRSA infection nor prior glycopeptide treatment. It is significantly associated with the occurrence of an infectious episode in the weeks preceding the transplant and with the administration of beta-lactams during the previous two months. Mortality is not increased in patients with hetero-GISA. NEW ANTIBIOTICS: Linezolide and quinupristine-dalfopristine are new agents available for the treatment of MRSA infection. Other antibiotics under development have demonstrated their activity: lipopeptides (daptomycin), semi-synthetic glycopeptides (oritavancin, dalbavancin), glycylglycines (tigecyclin), carbapenems (CP5609), and cephalosphorins (LB 11058). ANTIBIOTIC COMBINATIONS: Various studies have shown that antibiotic combinations must be used with care in the treatment of MRSA and GISA infections (glycopeptide intermediate strains) because of the antagonism between molecules belonging to different families.