[MRSA-induced prosthetic valve endocarditis complicated by synthetic graft infection that did not respond to repeated vancomycin administration but improved after surgery].

We performed AVR and OMC in a 55-year-old male with ASR complicated by MS and ASO. Postoperatively, an ulcer formed on the left lower extremity, resulting in methicillin-resistant Staphylococcus aureus (MRSA) infection. Axillo-bilateral-femoral artery bypass was performed using synthetic grafts. However, infection developed in the anastomosis site, leading to MRSA sepsis. Since MRSA is highly susceptible to vancomycin (VCM), this drug was administered at a dose of 1.5 g/day. With negative conversion of MRSA, the infected wound healed, and the general status improved. However, after discontinuation of VCM administration, sepsis recurred. VCM administration was resumed with prolongation of the administration period and an increase in the dose. Drug administration was discontinued 3 times after 2-4 weeks each, but recurrence was observed each time. During this period, AR due to prosthetic valve endocarditis (PVE) developed. AVR and MVR were performed again, and the synthetic graft was left in place. However, after discontinuation of postoperative VCM administration, infection of the synthetic graft was also demonstrated. The graft was removed, and revascularization was performed by another route. The patient improved after these procedures. When MRSA-induced PVE or synthetic graft infection develops, the infectious foreign material should be completely removed at an early stage before progression of tissue destruction or ulcer formation even if antibiotics are effective.