Chronic bacterial endometritis (inflammation of the inner uterine lining) in mares is a major source of economic loss to the breeding industry. This condition can be difficult to treat because in many cases the bacteria form a protective biofilm that antibiotics have trouble penetrating. Researchers from Colorado State University (CSU) wondered if some of the available antibiotic alternatives would do a better job getting through, so they conducted a study pitting these agents against various uterine pathogens.

Kristen Loncar, DVM, of CSU’s Equine Reproduction Laboratory, in Fort Collins, presented their results at the 2015 American Association of Equine Practitioners Convention, held Dec. 5-9 in Las Vegas.

“Because of the problems with antibiotic treatment (in cases of chronic or recurrent endometritis), we wanted to test the effects of nonantibiotic products,” Loncar said. “Some of the products (e.g., dimethyl sulfoxide, or DMSO) have been around for decades, while others (such as Ceragyn) are new on the market.”

She and her colleagues produced an in vitro (in the lab) biofilm from Streptococcus equi subspecies zooepidemicus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia isolates of mares diagnosed with endometritis. They tested nine agents’ (Ceragyn, DMSO, hydrogen peroxide, N-acetylcysteine, OmniPhase, Vetricyn, ozone, Tris-EDTA, and Tricide) ability to disrupt each bacterial species at recommended doses when challenged for six hours