Prosthetic biologic valve endocarditis caused by a vancomycin-resistant (vanA) Enterococcus faecalis: Case report

We recently observed (February 1999) a 68-year old patient with endocarditi s on a prosthetic biologic valve caused by a vancomycin-resistant Enterococ cus faecalis. Broth dilution tests showed susceptibility to ampicillin (MIC = 0.5 mug/ml), no high resistance to aminoglycosides (MIC for gentamicin < 500 <mu>g/ml) and resistance to vancomycin (MIC >256 mug/ml) and teicoplani n (MIC>16 mug/ml). A PCR assay detected vanA gene in this strain. A transth oracic echocardiogram did not show valvular vegetations. A possible endocar ditis was diagnosed and the patient received ampicillin for 8 weeks and gen tamicin for 6 weeks. The patient remained afebrile after a 4-month follow-u p when he underwent surgical replacement of the dysfunctional bioprosthetic valve. Mitral valve was sterile on culture, but histology confirmed the di agnosis of previous endocarditis, This is the third case of endocarditis ca used by vancomycin-resistant E. faecalis reported to date.