Incidence of postextraction bacteremia under penicillin cover in children with cardiac disease.

To assess the efficacy of penicillin prophylaxis as recommended by the American Heart Association to prevent the onset of bacterial endocarditis, the incidence of postextraction bacteremia was determined in 82 children with cardiac disease who were receiving prophylactic penicillin. Aerobic and anaerobic blood cultures were taken five minutes after dental extraction, as was a blood sample to assay the serum penicillin concentration. The incidence of postextraction bacteremia was 21%. Streptococcal species accounted for half of the number of aerobes isolated. Of the isolated microorganisms, 16% were strict anaerobes. Susceptibility testing of the isolates showed that 24 penicillin-sensitive and eight penicillin-resistant microorganisms caused the bacteremia. There was neither a significant difference between the serum penicillin concentrations of children with and without bacteremia, nor between the serum penicillin concentrations of children with bacteremia due to penicillin-sensitive microorganisms and children with bacteremia due to penicillin-resistant microorganisms. It is concluded that the occurrence of postextraction bacteremia is not prevented by penicillin prophylaxis and that the serum penicillin concentration at extraction is not the discriminating factor in preventing this bacteremia. None of the children developed bacterial endocarditis. It is speculated that mechanisms not thoroughly studied are involved in the prevention of bacterial endocarditis after dental extraction.