Endovascular infections caused by enterococci highly resistant to ampicillin.

Enterococci frequently cause endocarditis and are the most common gram-positive isolates in polymicrobial bacteremia. We report three cases of polymicrobial endovascular infections at a single institution during a 12-month period; the enterococcal isolates were highly resistant to penicillins. These cases comprised 18% of all enterococcal endovascular isolates during the same 12-month period. Previous use of antibiotics, presence of endovascular catheters, and nosocomial acquisition of the organism occurred in all three cases. Clinicians should be aware of enterococcal resistance to penicillins and should exercise care in designing appropriate regimens for serious enterococcal infections.