Geraci, J E

Checkerboard bactericidal studies were performed with two strains each of Streptococcus mitis, S. salivarius , and S. sanguis , and the results were analyzed by the use of isobolograms. Synergy between penicillin and streptomycin or gentamicin was demonstrated with four strains, representing two of S. salivarius , one of S. sanguis , and one of S. mitis ; the remainder were either too susceptible or too resistant to be analyzed. Clindamycin with streptomycin or gentamicin acted synergistically with three strains, representing two of S. sanguis and one of S. salivarius ; the remainder were either too susceptible or too resistant to be analyzed.

Thirty-three cases of enterococcal endocarditis encountered during the decade from January 1944 through December 1953 are reviewed. In vitro studies indicate that penicillin and streptomycin are the best antibiotic pair for bactericidal effect. Twelve of the last 14 patients were cured (86 per cent), 10 with combined therapy. The cure rate in enterococcal endocarditis now approximates that of endocarditis caused by penicillin-sensitive streptococci. A maximal number of cures is achieved by individualization of therapy. The daily dosage of penicillin and the duration of combined penicillin-streptomycin therapy should be guided by in vitro bactericidal tests employing the patient's strain of enterococcus.