Abstract: This study aimed to explore the in vitro inhibitory effect of compound Chinese herbal medicine on a clinical Staphylococcus isolate from canine. The water extracts of a total of 20 kinds of compound Chinese herbal medicine were prepared with 30 kinds of single Chinese herbal medicine based on the traditional compatibility principle by using decoction method. The minimum inhibitory concentration （MIC） of the compound Chinese herbal medicine against the isolate was determined by using tube double dilution method, and the diameter of inhibition zone was determined by using agar diffusion method. The results showed that the NO. 15 and NO. 16 compound Chinese herbal medicine had the best antibacterial activity against the clinical isolate in vitro, and both of their MIC against the isolate was 31.25 mg/mL. The diameter of the inhibition zone of the NO. 15 and NO. 16 compound Chinese herbal medicine against the isolate was 31.0 mm and 38.0 mm, respectively, indicating that the isolate was extremely sensitive to both of the compounds. In addition, the other compound Chinese herbal medicine also showed certain antibacterial activity against the isolate. Our results provide a scientific basis for screening of high-efficient and low-toxic compound Chinese herbal preparation for veterinary clinical use.

Key words: compound Chinese herbal medicine, canine staphylococci, antibacterial effect in vitro, minimum inhibitory concentration, inhibition zone diameter