Abstract:

【Objective】 The objective of the study was to evaluate the in vitro antibacterial activity and post-antibiotic effect of ceftiofur suspension on three standard bacteria strains in veterinary clinic. 【Method】 Minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested by double dilution method to three standard bacteria strains. Time-kill curve was drew according to colony count. Post-antibiotic effect (PAE) was determined by plate count. 【Result】 MIC value of ceftiofur suspension to E. coli, Actinobacillus and Streptococcus zooepidemicus was 0.076, 0.304, and 0.00475 μg•mL-1 respectively. MBC value was 0.61, 0.304, and 0.00475 μg•mL-1 respectively. Sterilization rate of ceftiofur suspension was the fastest to Actinobacillus, followed by Streptococcus. PAE of ceftiofur suspension was relatively short to E.coli, which illustrated that it was nonconcentration dependent. PAE was obvious longer to Actinobacillus, which showed that it was concentration dependent, however, it revealed part concentration dependent to streptococcus. 【Conclusion】Ceftiofur suspension can be widely used in veterinariy clinic due to its strong, immediate, and persistent sterilization.

Key words: ceftiofur suspension, minimal inhibitory concentration, minimum bactericidal concentration, time-kill curve, PAE