Abstract: The clinical pharmacodynamics of procaine penicillin-dihydrostreptomycin sulfate suspension against Streptococcosis suum experimentally induced in swine was studied in this paper. Minimal inhibitory concentrations (MICs) of penicillin and enrofloxacin for Streptococcus equisilis were determined to be 0.0313 and 0.5 mg/L by two-fold dilution method in vitro, respectively. Following the treatment with three different dosage of procaine penicillin-dihydrostreptomycin sulfate suspension (0.05 mL/kg穊w, 0.1 mL/kg穊w and 0.2 mL/kg穊w) and enrofloxacin (2.5 mg/kg穊w) against Streptococcosis suum for 3 consecutive days, the curative rates of the infected swine were 60%, 80%,90% and 60%, respectively. The mortality of the infected but untreated group was 70%.

Key words: penicillin G procaine; dihydrostreptomycin sulfate; Streptococcosis suum; pharmacodynamics experiments