Chemotherapy of Experimental Streptococcal Endocarditis. I. COMPARISON OF COMMONLY RECOMMENDED PROPHYLACTIC REGIMENS

Abstract

The effectiveness of various antibiotics commonly recommended for the prophylaxis of bacterial endocarditis has been evaluated in experimental streptococcal endocarditis in rabbits. High doses of penicillin G did not prevent the development of this infection. The only consistently successful prophylactic regimens using penicillin alone were those which provided for both an early high serum level and more than 9 h of effective antimicrobial action. Vancomycin was the only other drug which proved uniformly successful when given alone, even though the duration of its antimicrobial action in the blood was only 3 h. However, combined therapy using penicillin G or ampicillin with streptomycin was always effective in prophylaxis. Treatment with single injections of ampicillin, cephaloridine, cephalexin, clindamycin, cotrimoxazole, rifampicin, streptomycin, erythromycin, and tetracycline failed to prevent infection.The findings provide information on the effect of antimicrobials in vivo and may be applicable to the chemoprophylaxis of infective endocarditis in clinical practice.

Successful Single-Dose Amoxicillin Prophylaxis Against Experimental Streptococcal Endocarditis: Evidence for Two Mechanisms of Protection

“…Since clindamycin is bacteriostatic, these experiments provide further evidence that killing is not essential for effective prophylaxis. The results of both studies appear to contradict those of previous observations in rabbits by Durack and Petersdorf [5] and Pelletier et at. [12], in which single injections of several antibiotics failed to prevent infection.…”

“…This strain has been used in experiments on endocarditis in both rabbits [10] and rats [9,11]. (2) S. sanguis biotype II was provided by Dr. D. T. Durack (Duke University Medical Center, Durham, N.C.) who had used it in his investigations of prophylaxis against endocarditis in rabbits [5,12]. (3) Streptococcus mitior was isolated from a patient in Lausanne with endocarditis.…”

“…The rabbit model developed by Garrison and Freedman [4] was used to test several prophylactic antibiotic regimens. These experiments suggested that bactericidal antibiotics would have to be given to obtain adequate prophylaxis and that a synergistic combination of antibiotics would be more effective than a single agent [5]. In rabbits, parenteral penicillin and vancomycin have been shown to be effective in preventing bacterial endocarditis.…”

Single-Dose Rifampin Prophylaxis for Experimental Endocarditis Induced by High Bacterial Inocula of Viridans Streptococci

“…Four strains of viridans streptococci isolated from patients with endocarditis were used. Streptococcus intermedius and Streptococcus sanguis (originally provided by Dr. D. Durack, Duke University Medical School, Durham, NC) have previously been used in experiments in rabbits [10,11] and in rats [1-3, 6, 12]. In addition, two strains of Streptococcus mitis, S. mitis 1000 [6] and S. mitis 518, were selected.…”

Clindamycin and dentistry

“…38 Animal models of IE also reported erythromycin's failure as a suitable prophylactic agent. 39 Despite the change in recommendation, a recent study of prophylactic antibiotic prescribing within the National Health Service found that 18.6% of general dental practitioners would use erythromycin as a prophylactic agent in patients allergic to penicillin. 40 The suitability of clindamycin as an appropriate agent for the prophylaxis of IE has been demonstrated in the animal model.…”