A PK/PD model for the evaluation of clinical rifaximin dosage for the treatment of dairy cow mastitis induced by Escherichia coli

• Published in: BMC veterinary research 2023-01, Vol.19 (1), p.19-11, Article 19
• Main Authors: Wang, Honglei, Chen, Chen, Liu, Chunshuang, Chen, Xiaojie, Zhang, Jingju, Wang, Yufeng, Han, Mingyue, Liu, Yiming, Li, Xiubo
• Format: Article
• Language: English
• Subjects: Analysis; Animal lactation; Animals; Antibacterial activity; Antibiotics; Antimicrobial agents; Bacteria; Care and treatment; Cattle; Cattle Diseases; Chromatography; Colonies; Complications and side effects; Dairy cattle; Dairy industry; Diagnosis; Diseases; Dosage; Dosage and administration; Drug dosages; Drug resistance; E coli; Escherichia coli; Escherichia coli infections; Escherichia coli Infections - drug therapy; Escherichia coli Infections - veterinary; Experiments; Female; Genetic aspects; Growth; Laboratories; Lactation; Mammary gland; Mammary Glands, Animal; Mastitis; Mastitis, Bovine - drug therapy; Mastitis, Bovine - microbiology; Mice; Milk - microbiology; Milk production; Minimum inhibitory concentration; Monte Carlo simulation; Opportunist infection; Pathogens; Pharmacodynamics; Pharmacokinetics; PK/PD model; R&D; Research & development; Rifaximin; Rifaximin - therapeutic use; Udder
• ISSN: 1746-6148; 1746-6148
• DOI: 10.1186/s12917-022-03564-2

Escherichia coli (E. coli) is an opportunistic pathogen that can cause clinical mastitis in dairy cows worldwide. Mastitis produces severe symptoms in dairy cows, such as udder inflammation, the production of harmful substances, reduced milk production, and altered milk quality. Intramammary injections of rifaximin have a beneficial effect on dairy cow mastitis, especially for mastitis caused by E. coli. However, we do not know whether the currently accepted clinical administration scheme is reasonable. Therefore, the purpose of this experiment was to evaluate the clinical dosing regimen for curing mastitis induced by E. coli. In this study, the pharmacokinetics of four single dose groups (50, 100, 200, and 400 µg/gland) were studied in CD-1 lactating mice, and the main pharmacokinetic parameters were obtained by non-compartment and two-compartment model of Phoenix 8.1 software. A total of 5,000 colony-forming units (CFU) of E. coli ATCC25922 were injected into the mammary glands of mice under anatomic microscope guidance. After 12 h of growth in vivo, the mouse mastitis model was successfully developed. In pharmacodynamics experiment, 12 different dosing regimens (doses ranged from 25 to 800 µg/gland and two dosing intervals of 12 and 24 h) were used to study the therapeutic potential of rifaximin for mastitis. The PK/PD model was established by integrating pharmacokinetics and pharmacodynamics using the inhibitory sigmoid E model. The optimal antibacterial effect was 2log CFU/gland reduction of bacterial colony counts in vivo, when the magnitude of AUC /MIC exceeded 57.80 h. A total of 57.80 h of AUC /MIC was defined as a target value in the Monte Carlo simulation. The clinically recommended dosage regimen of 100 mg/gland every 12 h in a day achieved a 91.08% cure rate for the treatment of bovine mastitis caused by E. coli infection.