CHRONIC STAPHYLOCOCCAL MASTITIS: ERADICATION OF PATHOGENS THAT RESIDE INTRACELLULARLY
Animal Biosciences and Biotechnology Laboratory
Project Number: 1245-31000-103-04
General Cooperative Agreement
Start Date: Aug 27, 2010
End Date: Mar 14, 2013
Create triple-lytic-domain PG hydrolase-PTD fusions and test in cultured cells. Create triple-lytic-domain-PTD fusions via molecular techniques. Verify that the triple-lytic-domain-PTD fusions maintain three enzymatic activities. Test efficacy of the triple-lytic-domain-PTD fusions against extracellular staphylococci (S. aureus and CoNS) in broth cultures and against internalized S. aureus in cultured bovine mammary epithelial cells. Test efficacy of the Lyso-PTD fusion protein to cure chronic bovine mastitis. Induce S. aureus mastitis in cows and evaluate the triple-lytic-domain-PTD fusion for the ability to cure chronic mastitis via intramammary injections at dry off. Determine if the triple-lytic-domain-PTD kills staphylococci that reside in milk somatic cells. Characterize S. aureus isolates from this study that are resistant to the triple-lytic-domain-PTD. Determine if triple-lytic-domain-PTD fusion can kill staphylococci within mammary abscesses. Examine proteome differences between S. aureus grown in ex vivo milk vs. within chronically infected quarters.
Identify pregnant lactating cattle for purchase, house and monitor lactating cattle, infect them with S. aureus, monitor for chronic status of infection, dry-off the cattle, inject the cattle with the antimicrobial fusion protein during dry-off period, birth the calves, and monitor for eradication of pathogen in colostrum and milk following birth.