Bowls, Biofilms, and Pyometra

by | Dog Breeding, Dog Health

Lately, I’ve been thinking about biofilm. I know, it’s an odd topic. Several bloggers have been making seemingly outlandish claims relating biofilm to a huge array of dog problems. To check these claims out, I had been digging into biofilm when I came across new research from the AKC Canine Health Foundation linking biofilm to pyometra. That got my attention.

What is biofilm?

Biofilm is a sticky matrix of microorganisms, such as bacteria or fungi, that adheres to a surface. An example of biofilm that we are all familiar with is dental plaque. However, biofilms are found in other places, like dog food and water bowls, as well as in human and canine bodies. These networks of pathogens are increasingly dangerous, often causing chronic and dangerous infections. One of the hallmarks of biofilm infections is that they have “extreme resistance to antibiotics… and an extreme capacity for evading the host defenses.” (Bjarnsholt, 2013)

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What is pyometra?

Pyometra, otherwise known as pyo, is a uterine infection that strikes intact bitches. Most commonly, pyos occur in older bitches with age-related changes to their uteruses making them susceptible to infection. However, some pyos occur unexpectedly in young, healthy bitches that have no predisposing characteristics. These latter infections are particularly challenging and frustrating for us.

Can biofilm cause pyometra?

If the bacteria that cause pyometra, often E. coli, can also create biofilms, this might explain why these cases are difficult to treat and have a high rate of recurrence. Treatments for pyo cannot destroy the biofilm, allowing the bacteria to resist. New research from The Ohio State University and funded by the AKC CHF indicates that many pyometra-causing bacteria can indeed create biofilms, thus explain their resistant to treatment.

What else might biofilm do to our dogs?

In addition to pyometra, biofilms are hypothesized to cause other chronic infections in dogs and in people. These can include ear infections, vaginitis, urinary tract infections, gingivitis, prostatitis, and chronic wounds. I’m wondering if it doesn’t contribute to skin infections, like hot spots and pyoderma, too.

Where do dogs contact biofilms?

Assuming their teeth are plaque free, the most common places where dogs contact biofilm are their food and water bowls. According to NSF International, pet bowls are one of the top five dirtiest places in our homes. Biofilm, that clear or pink slime that coats the inside of the bowls, is the main culprit.

We don’t know that dog bowl biofilm contributes to pyometra or other chronic, hard-to-treat infections but the risk is there. Thus, good husbandry practices should cause us to remove these obvious sources of biofilm from our homes.

How do we eradicate biofilms?

Rinsing, even in super-hot water, isn’t enough to break up the biofilm network. Instead, dog dishes must be washed daily, either in a sanitizing dishwasher or scrubbed hard by hand with hot, soapy water, and then rinsed. If you hand wash rather than use the dishwasher, once a week you should soak the dishes for 10 minutes in a bleach solution of half a teaspoon of household bleach in a gallon of water and soak for about 10 minutes. Rinse thoroughly and allow to air dry before using again. I am not a fan of using bleach around dogs but I make an exception for biofilms.

I’m heading off scrub my dogs’ bowls. No more biofilm in this house!


Albright, A. 2018. Understanding the Role of E. Coli Biofilm in Canine Pyometra, American Kennel Club.

Bjarnsholt T, 2013. The role of bacterial biofilms in chronic infections, APMIS Supplement.

NSF, 2018. Help Your Pet Live Safer™. http://www.nsf.org/newsroom/help-your-pet-live-safer


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  1. Tammy

    Probiotic cleaner will help rid of biofilm

    Salmonella remains on pet bowls Interesting scientific research paper showing that
    Salmonella remains on pet bowls even after a hot wash in a dishwasher or being
    soaked in bleach. Its worth a read, especially if you feed your dogs in the
    kitchen and think that disinfection is removing pathogens http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1555674/

    • Gayle Watkins

      Tammy, Thanks for the study. I guess those results make me realize how lucky we all are that we don’t have salmonella infections daily. If salmonella remains on dog bowls, it also remains on kitchen counters, cutting boards, knives and all of the other things in our kitchens that we use to cook chicken and other poultry products. Raw dog food has no more salmonella than human food so the risks exist from both sources. I know very few people who scrub and bleach their kitchens regularly .

      Please feel free to share the research showing probiotic cleaners removing salmonella biofilms. I’d enjoy reviewing it!

  2. Deb

    What sbput dog toys??? Especially dogs that share toys!!

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