College of Agriculture & Natural Resources

Finding Alternatives to Antibiotics: Harnessing Viruses to Fight Bacteria in Dairy Cows

Dariy farm
Image Credit: 
Edwin Remsberg

A virus might not seem like the most effective way to fight an infection to most people, but as UMD Associate Professor Daniel Nelson explains, “The enemy of my enemy is my friend.” With UMD Assistant Professor Kasey Moyes of Animal and Avian Sciences as principal investigator, Nelson of Veterinary Medicine, Fellow of the Institute for Bioscience and Biotechnology Research (IBBR), recently received $500,000 from the United States Department of Agriculture to explore the use of viral enzymes to fight bacterial infections in dairy cows. By harnessing viral enzymes that naturally infect and kill bacteria of interest, Moyes and Nelson are developing creative solutions to not only fight a bacterial infection that causes the spoilage of $2 billion of milk each year, but to reduce the need for traditional antibiotics that are becoming less and less effective due to overuse and antibiotic resistance.

The Nelson Lab studies bacteriophage (sometimes just called phage) viruses that infect bacteria. In particular, the lab focuses on enzymes produced by phage that directly destroy bacterial cells. These enzymes may prove to be alternatives to antibiotics.

“Enzybiotics (for ENZYme antiBIOTICS) essentially break chemical ties in the bacterial wall, and the resulting high internal pressure within the bacterial cell causes it to explode and die,” explains Nelson.

For this grant, Moyes brings her expertise to the table to determine how effective the PlyC enzyme is at both treating and preventing bovine mastitis caused by Streptococcus uberis in lactating dairy cows. This infection is highly persistent, and with concerns about antibiotic resistance and consumer demand for antibiotic-free products, alternative methods are particularly important and economically attractive. Moyes will also look at management and regulatory issues that may need to be considered when introducing this new form of treatment.   

Meanwhile, the Nelson group will work on scaling up production to produce consistent, high-quality PlyC enzyme for this study and future applications. In addition, they will perform pre-clinical studies of how the enzyme works to kill the infection and explore how likely bacterial populations are to develop resistance to this new treatment.

“Beyond addressing the challenge of antibiotic resistance and reducing the rate of infection recurrence, PlyC is cleared by the system without any toxicity or chemical residue that may harm the animal as well as humans via consumption,” says Moyes.  “This would allow it to be implemented by both conventional and organic dairy producers.”

Nelson and Moyes will make their findings, tools, management strategies, and recommendations available to stakeholders, producers, veterinarians, and the public. Treatment will be examined in both the laboratory and farm environments to assess real-world and clinical efficacy. By exploring these antibiotic alternatives in animals, researchers are finding ways to reduce the load of antibiotics in the environment and humans as well, contributing to overall animal, environmental, and human health.

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