Enterococcal endocarditis: clinical and microbiological features of our series

Of 81 cases of infectious endocarditis seen at our institution from 1988 to 1995, 61 had positive culture (75%) and, of these, 10 (16%) were caused by enterococcal strains (9 by Enterococcus faecalis, 1 by Enterococcus faecium). The 10 cases consisted of 5 native valve endocarditis and 5 late prosthetic valve endocarditis. Median age of patients was 50 years (range 21-58); 6, were males. Diagnostic or surgical procedures on the abdomen, genito-urinary tract, or chest preceded the onset of fever in almost all cases. Nine enterococcal strains showed low-level resistance to aminoglycosides and one was highly resistant. Seven patients were treated with ampicillin and gentamicin and 2 with teicoplanin and gentamicin. The patient, whose infection was caused by an high gentamicin-resistant E. faecalis, was treated with the combination of ciprofloxacin and cotrimoxazole chosen on the basis of the in vitro susceptibility tests. Congestive heart failure occurred in 4 patients and major embolic events in 3. All patients were cured; 4, with medical therapy alone and 6, with antimicrobials associated with surgical substitution of the valve. The data indicate that enterococcal endocarditis, when treated with appropriate antimicrobial regimens, associated with surgical treatment when necessary, has a very low mortality rate. The conventional treatment, -lactams plus gentamicin is usually effective. However, for high-level gentamicin-resistant strains alternative treatments must be selected on the basis of the in vitro susceptibility tests.