Understanding the Role of E. coli Biofilm in Canine Pyometra

Pyometra, or uterine infection, remains a serious health threat for intact bitches. E. coli is the most common cause of canine pyometra and many strains of this bacteria are known to produce a biofilm. Biofilm is a surface layer of microbes and the slimy extracellular polymeric substances they produce (polysaccharides, proteins, etc.). Biofilms protect bacteria from the environment. In the body, this means protection against the host immune system and antibiotic therapy.

Scientists are already evaluating non-antibiotic treatments aimed at disrupting E. coli biofilm in horses with chronic endometritis (uterine infection/inflammation). Thanks to AKC Canine Health Foundation (CHF) grant 02264-A, researchers at Ohio State University recently started exploring the role of E. coli biofilm in canine pyometra. To see if E. coli biofilm plays a role in thwarting successful treatment of pyometra, Dr. Marco Coutinho da Silva and Dr. Tessa Fiamengo (2016 recipient of an AKC/AKC CHF/TF Theriogenology Residency) examined the ability of several pyometra-causing E. coli strains to produce biofilm in vitro (in the laboratory) and in vivo (in the uterus).

Endometrial (uterine lining) samples were obtained from 23 bitches spayed because of clinical pyometra. Samples were cultured to confirm the presence of E. coli and then preserved for additional testing. Twenty distinct isolates of E. coli were cultured from 16 of the tissue samples, and the majority of them demonstrated biofilm production as shown by diagnostic methods that included optical density testing, histopathology, genetic identification with fluorescent in situ hybridization (FISH), and scanning electron microscopy. Dr. Fiamengo won the Abstract Competition at the 2017 Annual Conference of the Society for Theriogenology for her presentation of this important research, and the results are being prepared for publication.

This pilot study confirms the ability of E. coli to create biofilm in canine pyometra. AKC Canine Health Foundation is committed to advancing the health of all dogs by funding scientific research to prevent, treat and cure canine disease. Funding has already been provided for studies to examine E. coli genetics, surface binding capabilities, and antimicrobial resistance patterns in pyometra. The knowledge gained may give veterinarians and breeders an advantage in disrupting E. coli’s ability to adhere to the uterine lining and create biofilm, leading to new therapeutic approaches to pyometra.

UPDATE: Study results were published in the June 2020 issue of Topics in Companion Animal Medicine. Read the full publication at https://doi.org/10.1016/j.tcam.2020.100429.