Researchers Link Red Complex Bacteria, EOTRH

Researchers Link Red Complex Bacteria, EOTRH

“It is always important to know the etiology (cause) of a disease for a better treatment and especially for prevention,” she said. “So if you can treat a problem in an early stage with specific therapy, you will be more successful.”

Photo: Adam Spradling/The Horse

When it comes to periodontal disease, red complex bacteria could be a red flag for impending tooth reabsorption.

Austrian researchers recently determined that the presence of red complex bacteria in crevicular fluid (the fluid coming from between the tooth and the gum) could mean a horse has a greater chance of having equine odontoclastic tooth resorption and hypercementosis (EOTRH).

“Finding red complex bacteria when there is periodontal disease in horses is important for a differential diagnosis of early stage EOTRH,” said Sabine Sykora, PhD, of the Equine Clinic at the University of Veterinary Medicine, in Vienna, Austria.

In her pioneering study, Sykora and her fellow researchers successfully isolated red complex bacteria DNA in association with EOTRH. This type of bacteria is commonly found in humans with periodontal disease, but Sykora’s study is the first to detect this marker in equids.

Red is not the bacteria's actual color; it’s part of a color code created for classifying bacteria according to their severity. Red bacteria are more pathogenic—more likely to cause disease—than orange or green, for example, Sykora said.

In horses with EOTRH, the tooth roots begin to disappear and cause the tooth—usually one of the front teeth (the incisors)—to become loose. The condition is painful and causes the teeth to shift around. It can also cause a condition called “hypercementosis”—meaning the roots create extra bony “cement” that actually protrudes out of the gums, Sykora added. Horses will often have difficulty eating or stop eating. Veterinarians confirm the disease using radiographs (X rays), which will show “more deformation than absorption,” she said.

In their study the Austrian researchers screened DNA from the crevicular fluid of 23 EOTRH horses and 21 healthy horses. They were looking for three types of red complex bacteria: Treponema ssp., Tannerella ssp., and Porphyromonas gingivalis. They found that Treponema and/or Tannerella were present in all 23 samples from EOTRH horses, as opposed to 52% of the samples from healthy horses, Sykora said. P. gingivalis was only present in 3% of the EOTRH samples.

The fact that more than half the healthy horses had red complex bacteria in their mouths was “not unexpected,” Sykora said, as the horses could have picked up the bacteria from their stablemates through shared equipment, stalls, and other materials. However, individual immune status to the bacteria “very likely represents a crucial factor” in warding off periodontal disease, she said.

The identification of red complex bacteria in association with EOTRH could lead to better preventive care and early disease management, said Sykora. “It is always important to know the etiology (cause) of a disease for a better treatment and especially for prevention,” she said. “So if you can treat a problem in an early stage with specific therapy, you will be more successful.”

The study, "Isolation of Treponema and Tannerella spp. from equine odontoclastic tooth resorption and hypercementosis related periodontal disease," was published in the Equine Veterinary Journal

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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