Pathogenesis and treatment of enterococcal infections

The pathogenesis and treatment of enterococcal infections are reviewed. Bactericidal activity is needed for treatment of endocarditis and meningitis, but penicillin and even vancomycin are not reliably bactericidal for enterococci. An aminoglycoside can be added for synergy, but enterococcal resistance to aminoglycosides is increasing. Urinary-tract infections are the most common source of enterococcal bacteremia and subsequent endocarditis. Enterococcal meningitis tends to occur in patients with history of urinary-tract disease, anatomic defects of the central nervous system, previous neurological procedures, or enterococcal endocarditis. The pathogenic potential of enterococci in abdominal infections is unclear. An increased incidence of enterococcal infections is associated with growing use of broad-spectrum antibiotics, particularly cephalosporins. Enterococci are susceptible to most penicillins except the antistaphylococcal agents, and urinary-tract infection is easily treated with a penicillin alone. For treatment of endocarditis and meningitis, a penicillin plus an aminoglycoside (such as streptomycin or gentamicin) must be used. In penicillin-allergic patients, vancomycin, preferably with an aminoglycoside, is the drug of choice. Cephalosporins, including all third-generation agents, have little or no activity against enterococci.