Enterococci. Biologic and epidemiologic characteristics and in vitro susceptibility

Abstract
Enterococci cause urinary tract infection (usually asymptomatic), 5-15% of [human] cases of endocarditis and rare cases of meningitis. Their role in polymicrobial infection in the abdomen and pelvis is difficult to assess. Ninety percent of enterococci are inhibited by 4 mg/l of penicillin G, by 2 mg/l of ampicillin and by 6 mg/l of vancomycin. The penicillinase-resistant penicillins, cephalosporins, carbenicillin and ticarcillin are at least 4-fold less active against enterococci than penicillin g; piperacillin has activity equivalent to penicillin G. The addition of an aminoglycoside to penicillin, ampicillin, vancomycin or piperacillin, which are not bactericidal against most strains of enterococci, results in more rapid and complete bactericidal activity (i.e., synergistic activity).