关键词: 鸭疫里默氏杆菌, 中药组方, 抗菌作用, 网络药理学

Abstract: To screen the traditional Chinese medicine formula with strong antibacterial effect on Riemerella anatipestifer（RA）and explore its antibacterial mechanism，the Oxford cup method was used to determine the diameter of antibacterial circle of 55 traditional Chinese medicines against RA，and the minimum inhibitory concentration（MIC）and minimum bactericidal concentration（MBC）of highly sensitive and above traditional Chinese medicines were determined. Three traditional Chinese medicines with the best inhibitory and killing effect were selected，and L₉（ 3³）orthogonal test design was carried out with 1×MIC，5×MIC and 10×MIC as three levels.The traditional Chinese medicine formula with the best antibacterial effect was screened out，and the network pharmacology method was used to explore the antibacterial mechanism of the formula. The results showed that among the 55 tested traditional Chinese medicines，four induced extremely sensitive and highly sensitive responses in the RA model，respectively.The best inhibitory effect was from Coptidis Rhizoma，Sappan Lignum and Schisandrae Chinensis Fructus.MIC of Coptidis Rhizoma was 15.63 mg/mL，MBC was 31.25 mg/mL.The MIC and MBC of Schisandrae Chinensis Fructus and Sappan Lignum were both 31.25 mg/mL and 62.50 mg/mL，respectively.The results of orthogonal test showed that when Rhizoma Coptidis was 78.15 mg/mL，Schisandrae Chinensis Fructus was 312.5 mg/mL and Sappan Lignum was 312.5 mg/mL，the diameter of inhibition zone was 20.05 mm，which had the best antibacterial effect on RA and reached the extremely sensitive level. The results of network pharmacology showed that there were 13，12 and 18 chemical components related to antibacterial effect of Coptidis Rhizoma，Schisandrae Chinensis Fructus and Sappan Lignum，respectively，and the corresponding targets of chemical components of each Chinese medicine were 146，327 and 154，respectively. A total of 1 431 targets related to antibacterial effect were obtained by database retrieval，and there were 22 common intersection targets of three traditional Chinese medicines and antibacterial effect.The key proteins included RAC‑α serine/threonine protein kinase，focal adhesion kinase 1，epidermal growth factor receptor，etc.GO enrichment analysis showed that antibacterial‑related genes of the Coptidis Rhizoma‑Schisandrae Chinensis Fructus‑Sappan Lignum combination were enriched in three categories：biological process（BP），cellular component（CC）and molecular function（MF）.The BP terms were mainly related to PI3K/AKT signaling pathway regulation，protein autophosphorylation，and positive regulation of cell migration；the MF terms mainly centered on protein kinase activity，kinase activity and protein tyrosine kinase activity. KEGG enrichment analysis identified multiple key pathways including VEGF，Rap1，HIF‑1 signaling pathway and adherens junction pathway.These results indicated that the combination exerted antibacterial，anti‑inflammatory and immunoregulatory effects via synergistic regulation of multiple signaling pathways.In summary，the screened compound formula consisting of Coptidis Rhizoma，Schisandrae Chinensis Fructus and Sappan Lignum exerts potent antibacterial activity against RA.This study preliminarily elucidates the synergistic antibacterial mechanism of the three herbs.The findings are of great significance for reducing antibiotic consumption and lowering the risk of bacterial drug resistance，and also provide a green alternative strategy for the prevention and treatment of Riemerella anatipestifer.

Key words: Riemerella anatipestifer, Traditional Chinese medicine formula, Antibacterial effect, Network pharmacology