Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with significant risk of mortality, especially when it occurs while on appropriate antimicrobial therapy. We herein describe an unusual case of a patient with prosthetic aortic tissue valve, who suffered from central venous catheter related MRSA bacteremia with septic thrombus formation in the superior vena cava. MRSA bacteremia persisted despite removal of the catheter and appropriate antimicrobial therapy including vancomycin, rifampin, and daptomycin. Subsequently, the MRSA strain exhibited de novo resistance to vancomycin, rifampin and daptomycin. Eventually, salvage combination therapy with high dose daptomycin and trimethoprim-sulfamethoxazole was successful and achieved clearance of MRSA bacteremia. The case illustrates the growing complexity of treating MRSA infections.

Rapid progression of valvular stenosis in the setting of infective endocarditis is extremely rare. Here we describe a patient with Bartonella endocarditis on a bioprosthetic aortic valve that caused rapidly progressive aortic stenosis without regurgitation. At operation the bioprosthetic valve was severely fibrotic and calcified, with markedly thickened and distorted leaflets and circular partial detachment from the aortic ring. The patient underwent aortic root replacement with aortic bioprosthesis and aortic grafting with reimplantation of the coronary ostia.