title: Efficacy of orally administered penicillin V for prophylaxis of experimentally induced streptococcal endocarditis.
abstract: Four oral penicillin V regimens were compared for the ability to prevent Streptococcus sanguis infection of experimentally induced valvular heart lesions in rabbits. Challenge doses of 10(4), 10(6), and 10(8) CFU of a penicillin-susceptible strain of S. sanguis were used in this study. Measured by recovery of test organisms from endocardial lesions, the lowest-concentration inoculum was infective for 53% of the recipients; the higher-concentration inocula were infective for all recipients. A single-oral-dose penicillin V regimen (36 mg/kg of body weight) prevented endocarditis when rabbits were challenged with 10(4) CFU, but protection diminished with increasing inoculum concentrations. In contrast, addition of a second penicillin V dose (18 mg/kg of body weight) administered with a 7-h interval between doses achieved fully effective prophylaxis against even the highest inoculum tested (10(8) CFU). A repeated set of experiments in which half the dose of penicillin V was administered showed significantly reduced protection against S. sanguis endocarditis.
mesh_terms: D000328:Adult; D000818:Animals; D004697:Endocarditis, Bacterial / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D010404:Penicillin V / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use*; D011817:Rabbits; D013290:Streptococcal Infections / Q000517:prevention & control*; D013298:Streptococcus sanguis / Q000187:drug effects
chemical_list: D010404:Penicillin V