Several case series suggest that it may have utility in complicated S aureus infections, including These promising observations should be verified with appropriately designed clinical studies before ceftaroline can be recommended for widespread use in such off-label settings. Recommendations 1. Routine use of rifampin is not recommended for treatment of staphylococcal NVE (Class III; Level of Evidence B). 2. IE caused by vancomycin-resistant staphylococci (hVISA, VISA, or VRSA) should be managed in conjunction with an infectious diseases consultant (Class I; Level of Evidence C). IE Caused by Staphylococci in the Presence of Prosthetic Valves or Other Prosthetic Material Coagulase-Negative Staphylococci CoNS that cause PVE usually are methicillin resistant, particu- larly when IE develops within 1 year after surgery.182 Unless susceptibility to methicillin can be demonstrated conclusively, it should be assumed that the organism is methicillin resistant, and treatment should be planned accordingly. Experimental IE models caused by methicillin-resistant staphylococci demon- strated that vancomycin combined with rifampin and gentami- cin is the optimal regimen, and limited clinical reports support The dosing of rifampin is done by convention and is not based on PK data. Vancomycin and rifampin are rec- ommended for a minimum of 6 weeks, with the use of gen- tamicin limited to the first 2 weeks of therapy (Table 11). If the organism is resistant to gentamicin, then an aminoglycoside to which it is susceptible should be substituted for gentamicin. Some authorities recommend delaying the initiation of rifampin therapy for several days to allow adequate penetration of van- comycin into the cardiac vegetations in an attempt to prevent treatment-emergent resistance to rifampin. If the organism is resistant to all available aminoglycosides, such adjunctive treatment should be omitted. 