Dr. Stuart Price is an associate professor in the Department of Pathobiology in the College of Veterinary Medicine. He has been an affiliate faculty member at AUFSI since 2013, having served as team leader of our Salmonella working group and as a key member of our antimicrobial resistance working group. Price’s current research is focused on reducing Salmonella in food animals, such as chicken and cattle, through antibiotic alternatives such as bacteriophage treatment as well as detecting routes of Salmonella transmission between different animal species.
FSI: What are your most recent results/data from your bacteriophage research trials?
SP: We have just begun experiments to determine if bacteriophages can decrease Salmonella numbers on surfaces, such as concrete and stainless steel. These surfaces are commonly used in food animal production. To date, we’ve seen a 100-fold reduction in Salmonella Muenster that was experimentally applied to a chip of concrete and treated with an S. Muenster-targeted bacteriophage.
FSI: Relating to a second part of your research, have you discovered routes of transmission of Salmonella between different animal species, and what are they? And have you begun looking into intervention strategies to slow or prevent this transmission?
SP: We have performed fairly extensive environmental sampling of the vet school food animal facilities and the Equine Reproduction Center. At first we were surprised to find so many environmental sites contaminated with Salmonella, until we realized that the CVM’s dairy herd was colonized with three serotypes of this pathogen, which entered the environment through fecal contamination. Cattle are not uncommon carriers of Salmonella, and some serotypes move between members of these close-knit herd animals without causing widespread disease signs. What did surprise us was finding these same three Salmonella serotypes in the Equine Reproduction Center environment. Salmonella is more apt to cause serious disease in horses, compared to cattle, although foals and calves both can succumb to salmonellosis. We do not know if the three Salmonella serotypes entered the two animal facilities independently, or spread from one to another. Biosecurity measures being put into place currently are designed to prevent transmission of Salmonella to other animals and people.
FSI: Do you have any other specific areas of interest – anything you’d like to study that you haven’t already?
SP: We would like to use chicken eggs to test the efficacy of bacteriophage therapy, using an assay called the chicken embryo lethality assay. We previously developed a calf model of salmonellosis, which showed that Salmonella-targeted bacteriophages reduce the number of Salmonella in the feces of experimentally infected calves while at the same time preventing the normal signs of fever and diarrhea that are hallmarks of salmonellosis. But we need to optimize the bacteriophage therapy protocol by determining which phages are most active, and the minimum dose of phages that it takes to show a therapeutic response. These types of experiments would require many calves to complete. We plan to first perform these experiments in Salmonella-infected chick embryos to substantially reduce the number of calves needed to optimize our phage therapy protocol.
FSI: What classes are you currently teaching/coordinating in the vet school?
SP: I coordinate a course entitled Bacteriology & Mycology in the veterinary curriculum, and I am course director of a graduate course entitled Bacterial Pathogenesis. I also give lectures in several other vet school graduate courses coordinated by other instructors.
FSI: How do you balance research and teaching effectively?
SP: The key to performing good research is to recruit hard working people into your laboratory. Having those lab workers in place allows me to invest quality time in preparing, updating, and presenting good lectures to the veterinary and graduate students. Then I can focus my efforts on writing competitive grants and submitting manuscripts for publication.
FSI: How and why did you become interested in studying bacterial pathogens, particularly Salmonella?
SP: My training and background is in the field of Microbiology, specifically, Bacteriology. My Ph.D. work and one of my postdoctoral positions were in human medical centers, so I studied human bacterial pathogens during my training years. When I arrived at the vet school, I discovered that many foodborne pathogens, such as Salmonella, are transmitted to humans from infected animals, often through contaminated food or water. So I began working in the area of pre-harvest food safety and Salmonella because it was a natural fit for me – this pathogen causes serious disease in animals, from which it moves into people.