Isolation and Characterization of Naturally Occurring Bacteria from Equine Uterus

By Samantha Howe

My current project is focused on characterizing the microbiome of the equine uterus. During my time as an Animal Science Research Scholar in Dr. Udaya DeSilva’s laboratory, I helped with a project aimed at identifying bacterial species that inhabit healthy equine (horse) uteri.

There are numerous steps involved in this project. I start by receiving uterine fluid samples from healthy mares. Next, I plate the samples onto both Blood and MacConkey agar plates. Once I have bacterial growth, I perform single colony purification and send each culture to the Oklahoma Animal Disease Diagnostics Lab (OADDL) to be identified. If the lab is unable to identify the samples, I culture them in Terrific Broth. Once growth occurs, I perform DNA extraction. Next, I perform PCR regions on V1-V9 of the 16s ribosomal RNA. Upon completion, I send the samples for sequencing.

Samantha Howe

Photo by Rebekah Alford

The study identified 160 different genera of bacteria that live in the uteri of healthy mares. Some of these organisms have never been reported before and none have ever been reported in the uteri of mares. I am interested in two of these organisms that sometimes represent 50% or more of the bacteria found in some mares. One is an organism that belongs to the genus Pseudomonas and the other is an organism that belongs to the genus Terisoporobacter.

I am interested in the Pseudomonas organism because of another bacterium belonging to the same genus, Pseudomonas aeruginosa. Pseudomonas aeruginosa is a known pathogen in human and animal reproductive tracts, however the Pseudomonas sp. I am studying seems to thrive in healthy animals. In addition, I am also interested in Terisoporobacter, because it has never before been reported in an animal.

Mares with their foals at the Oklahoma State University Equine Center.

Photo by Rebekah Alford

The goal of my current research project is to biochemically and microbiologically characterize microbial populations in healthy equine uteri in order to determine their function and purpose. In doing so, I hope these organisms could someday be used as probiotics in mammalian reproductive tracts to treat issues like infertility and endometriosis.

Agar plate with bacterial growth

Photo by Rebekah Alford

The mammalian uterus has always been considered a sterile, pristine environment to be able to sustain a fetus. Any indication of the presence of an extraneous organism called for intervention with broad-spectrum antibiotics and antifungal agents. This paradigm has recently been challenged by the observation of commensal bacteria in healthy human placenta. Subsequently, many laboratories (including the laboratory I work in) have proven that a dynamic bacterial population exists in the uteri of several mammalian species. However, the current veterinary/medical approaches call for comprehensive antibiotic treatment of uteri at the first indication of infection. The function, if any, of most of these bacteria are not known at this time. My research is important because if I am successful, these organisms could someday be used as probiotics in mammalian reproductive tracts.

Samantha Howe

Photo by Rebekah Alford

About Samantha Howe

In addition to the Niblack Research Scholar Program, Samantha has also been involved in the OSU Animal Science and Food Sciences Undergraduate Research Program. Samantha believes this program was incredibly beneficial to her undergraduate research career by providing her the opportunity to discover her passion for research.

During the summer of 2018, Samantha served as a Summer Undergraduate Research Fellow at the University of Texas Southwestern Medical Center in Dallas, Texas. During this time, she worked in the McFadden Laboratory in the Departments of Biochemistry, Endocrinology, and Internal Medicine. At UTSW, she had a multitude of responsibilities and projects, but the research project she worked on focused on Ewing Sarcoma, a rare form of cancer that affects the bone and surrounding soft tissue in children.

After graduation, Samantha plans to continue her education by attending graduate school. Her long-term goal is to remain in academia as a research scientist and professor. Samantha says she has a passion for science and knowledge that she hopes to pass on to the next generation of students.

“My mentors have continuously encouraged me and challenged me to reach my full potential,” Samantha said. “This empowerment has given me the confidence to reach for my dreams, no matter how lofty they may be. I hope to challenge and empower the next generation of students, as I have been.”