Enterococcal endocarditis, treatment

It is used in all forms of tuberculosis along with other antitubercular drugs. Other indications are tularemia, plague, brucellosis, bacterial endocarditis, entero-coccal endocarditis. Used concomitantly with penicillin G for synergistic effect in the treatment of enterococcal endocarditis when other antibiotics are ineffective or contraindicated. 

Antimicrobial combination therapy is used frequently to treat serious infections. Combination therapy may be used prior to knowing the pathogen or antibiotic susceptibility for the treatment of infections in neutropenic patients and in patients with enterococcal endocarditis or bacteremia, sepsis, or pneumonia caused by P. aeruginosa. In these cases, it is important to know whether the combination will have beneficial (or detrimental) effects on the overall antibacterial activity of the regimen. For example, the combination may result in activity that is... 

The most obvious example of the use of synergy is the treatment of enterococcal endocarditis. The causative organism is usually only inhibited by penicillins, but it is killed rapidly by the addition of streptomycin or gentamicin to a penicillin. The need for bactericidal activity in the treatment of endocarditis underscores the need for these synergistic combinations. 

Wilson WR, Wilkowske CJ, Wright AJ, et al. Treatment of streptomycin-susceptible and streptomycin resistant enterococcal endocarditis. Ann Intern Med 1984 100 816-823. 

Streptomycin, an aminoglycoside antibiotic (1 g IM q 12 honrs for two weeks then 500 mg IM q 12 hours for four weeks with penicillin), is indicated in primary and adjnnctive treatment in tuberculosis, for enterococcal endocarditis, and for tularemia. Streptomycin and penicillin prodnce a synergistic bactericidal effect against strains of enterococci, group D streptococci, and the varions oral streptococci of the viridans group. 

However, gentamicin has almost entirely replaced streptomycin for treatment of endocarditis caused by these microorganisms. Penicillin G alone is ineffective in the therapy of enterococcal endocarditis, and either streptomycin (500 mg twice daily) or gentamicin (1 mg/kg three times daily) must also be given to ensure a cure. Gentamicin is preferred when the strain is resistant to streptomycin. Both penicillin G and the aminoglycoside are administered for 4 to 6 weeks. 

Bacterial Endocarditis Streptomycin and penicMn in combination are synergisticaUy bactericidal in vitro against strains of enterococci, group D streptococci, and the various oral streptococci of the viridans group. A combination of penicUhn G and streptomycin may be indicated for treatment of streptococcal or enterococcal endocarditis. Streptomycin largely has been replaced by gentamicin but may still be used when the strain is resistant to gentamicin and susceptible to streptomycin. 

In penicillin-allergic patients, vancomycin is an effective alternative for the treatment of endocarditis caused by viridans streptococci or, combined with an aminoglycoside, for enterococcal endocarditis. Vancomycin has become an important antibiotic in the management of known or suspected penicillin-resistant pneumococcal infections. 

A patient needs antibiotic treatment for native valve, culture-positive infective enterococcal endocarditis. His medical history includes a severe anaphylactic reaction to penicillin G during the past year. The best approach would be treatment with (A) Amoxicillin/clavulanate Aztreonam... 

In a patient with culture-positive enterococcal endocarditis who has failed to respond to vancomycin because of resistance, the treatment most likely to be effective is... 

E) Gentamicin is used with ampicillin for synergistic effects in the treatment of enterococcal endocarditis... 

Tobramycin is almost identical to gentamicin in both its pharmacodynamic and pharmacokinetic properties. However, it is much less active than either gentamicin or streptomycin when used in combination with a penicillin in the treatment of enterococcal endocarditis. The answer is (E). 

Shanson DC. New guidelines for the antibiotic treatment of sheptococcal, enterococcal and staphylococcal endocarditis. J Antimicrob Chemother 1998 42 292-296. 

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