New Strain of Bacterium Identified in a Mare

Depending on a mare's reproductive conformation and breeding history, she could have any number of bad bugs in her reproductive tract that might hinder conception. As if there weren't enough bacteria to worry about, a research team in Germany has discovered a novel bacterium in a mare's vagina.

Discovering new bacteria is a relatively rare occurrence in veterinary medicine, but microbiologist Atteyet-Alla Fetouh Yassin, PhD (habil.), from the Institute of Medical Microbiology and Immunology at Bonn University in Germany, recently identified Arthrobacter equi sp. nov. This microorganism is far from being the next big thing, however, as it does not appear to be pathogenic (disease-causing) in horses.

Yassin and colleagues originally isolated the bacterium in 1996 from a mare's vaginal swab that was sent to Yassin's laboratory. Using simple identification techniques (because the case presented before the widespread use of advanced molecular techniques such as RNA analysis), Yassin and colleagues tentatively identified the bacterium as belonging to the genus Arthrobacter--a Gram-positive bacteria prevalent in many soils and in extreme environments including the Arctic Sea, near leaking radioactive waste tanks, and in distilled water.

Unsatisfied with the 1996 identification of the bacteria, Yassin explained that he and his coworkers recently elected to revisit the case using more advanced technology: "Today, in order to achieve exact identification of any bacteria, we use molecular biological methods (e.g., 16S rRNA gene sequence analysis and chemical analysis of cellular components), which was the case with the new bacterium."

Yassin advised that to be able to determine if any bacterium has a pathogenic potential, it should be isolated more than once and should also be associated with a common disease (e.g., zoonotic abortion), which is not yet the case with this Arthrobacter. It is also unlikely that the bacterium will be widely screened for, unless it begins appearing regularly on vaginal swabs.

John F. Timoney, MVB, MRCVS, MS, PhD, from the Gluck Equine Research Center at the University of Kentucky added, "There is no evidence that I am aware of that this organism is pathogenic for the horse."

Without information about the clinical condition of the reproductive tract of the mare from which the organism was isolated, making any inferences regarding this bacterium's impact on horses is not possible.

Although this particular bacterium is not likely to be pathogenic, horse owners can take comfort in knowing that should a new bacterium emerge and start causing disease, microbiologists are armed and ready with advanced molecular technology to rapidly identify it, allowing veterinarians to step in to quickly control and contain disease.

The study, "Arthrobacter equi sp. nov., a novel bacterium isolated from a veterinary clinical material," will be published in a future edition of the International Journal of Systematic and Evolutionary Biology. The abstract is currently available on PubMed.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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