To investigate the prevalence and drug resistance of pathogenic bacteria causing bovine mastitis in the Ningxia region，a total of 1 011 mastitis samples were collected from 16 dairy farms in Ningxia between 2022 and 2023.Pathogenic bacteria were isolated and identified using methods including isolation and cultivation，Gram staining，differential culture media，and 16S rDNA gene detection and sequencing.The isolated strains were subjected to drug susceptibility testing using the microbroth dilution method，followed by resistance.Carbapenem-resistant Escherichia coli （CRE） was screened from the identified E. coli isolates，and the antibacterial effect of tannic acid combined with amikacin on CRE was investigated.A total of 1 808 pathogenic strains were isolated and identified.Among them，Staphylococcus had the highest isolation rate at 29.42%，followed by Escherichia at 18.03%，while the isolation rates of other genera ranged from 1.05% to 9.46%.Drug susceptibility testing showed that Gram-positive bacteria exhibited the highest resistance to penicillin at 76.34%，whereas Gram-negative bacteria showed the highest resistance to cephalexin at 79.35%.The combined use of tannic acid and amikacin resulted in complete rupture of CRE cells，severe damage to the cell membrane，increased nucleic acid leakage，and a significant rise in ROS levels.The above results indicate that the primary pathogenic bacteria causing bovine mastitis in the Ningxia region are Staphylococcus and E. coli，which exhibit the highest resistance to β-lactam antibiotics.Additionally，the combination of tannic acid and amikacin significantly enhanced antibacterial activity against CRE.