EFFECT OF GENTAMICIN DOSING INTERVAL ON EFFICACY OF PENICILLIN OR CEFTRIAXONE TREATMENT OF EXPERIMENTAL ENDOCARDITIS DUE TO PENICILLIN-SUSCEPTIBLE, CEFTRIAXONE-TOLERANT VIRIDANS GROUP STREPTOCOCCI

The efficacy of ceftriaxone or penicillin alone or combined with genta micin at different dosing intervals was evaluated in experimental endo carditis due to a penicillin-susceptible, ceftriaxone-tolerant strain of Streptococcus sanguis I. The difference between monotherapy with ce ftriaxone and procaine penicillin approached statistical significance (P = 0.052). Ceftriaxone combined with gentamicin administered as a si ngle daily dose was less effective than was procaine penicillin combin ed with gentamicin administered in a single daily dose or in three div ided doses.