Not the Usual Suspects - Understanding the Bacterial Populations of Septic Arthritis Cases in Feedlot Cattle
Project Title
Genomic Discovery and Elucidation of Highly Unusual and Novel Microbes in Septic Arthritis Tissues of Feedlot Cattle
Researchers
Dr. Andrea Cameron - University of Regina andrew.cameron@uregina.ca
Dr. Murray Jelinski, Western College of Veterinary Medicine Dr. Tony Ruzzini, Western College of Veterinary Medicine
| Status | Project Code |
|---|---|
| In progress. Results expected in December, 2024 | POC.35.23 |
Background
Septic arthritis (SA), also commonly referred to as joint infections are typically seen in young calves as a secondary infection to navel infections after not receiving enough colostrum or receiving it too late and presents shortly after birth. This causes joint swelling and acute pain which results in underperforming, lame calves. However, there are more and more cases presenting at the feedlot. While a significant cause of lameness, it also packs a higher fatality rate than other causes of lameness accounting for almost 50% of lameness related deaths. These mortalities are also occurring later in the feeding period, meaning producers are not only eating the death loss but also the cost in feeding that animal for most of the feeding period. This not only hurts the pocketbook of producers but is a serious animal welfare concern. With the currently available culture-based diagnostic technology, researchers have routinely identified Mycoplasma bovis and Histophilus somni as the main culprits in these joint infections. However, new studies using DNA sequencing may have a different story to tell.
Objectives
- Identify mystery organisms found in SA infections from a previous study to understand how they contribute to SA infection.
What they will do
This team will take SA samples from a previous study that were found to be high in the mystery organisms (phyla NA 1 and phyla NA 2) and subject them to DNA sequencing strategies to attempt to classify them and understand their role in the infection. First will be an expanded sequencing of the gene typically used to recognize organisms, which has been unrecognizable up to this point, hence our interest in “mystery phyla” of putative bacteria detected genetically in the infected tissues. Next, primers will be designed to target the DNA sequences unique to NA1 and NA 2 to expand sequencing out from the currently identified sequence. Finally, shotgun metagenomics and bioinformatics will be used to enrich the DNA sequences which will provide insight on some of their functions and will further help to classify all microbes, metabolic pathways, and the putative new phyla in the samples.
Implications
Septic arthritis is a persistent health challenge in cattle operations in the Canadian prairies and across North America. There is a need for more effective diagnostics to inform treatment and herd management in feedlots to reduce risks of septic infection. Being able to identify organisms that are unique to SA infection is important to improve diagnosis and to better establish methods of treatment for those specific agents. Metagenomics and new long-read DNA sequencing technologies are a great opportunity to expand on culture-based diagnostics and gain insight on samples which are known to have low microbial mass and typically have many microbes contributing to the infection.