Q:What causes the slime in my dogs’ water bowls? Is it harmful?
A:It’s called a biofilm, and it’s composed of bacteria embedded within a slime produced by the microbes themselves. Biofilms adhere to living and non-living surfaces.
When a biofilm forms on teeth, it’s called plaque. Persistent urinary tract infections often result from a biofilm that clings to the inside surface of the bladder. When an infection involves a catheter or orthopedic implant, it’s usually due to a biofilm.
Biofilms protect bacteria from the environment, including the animal’s immune system and antibiotics. Successful treatment requires exceedingly high doses of antibiotics, removal of surgical implants and other extreme measures. Therefore, veterinarians focus on preventing biofilm formation through such methods as sterile technique and short duration of catheter use, particularly with urinary catheters.
As a biofilm grows in the body, some bacteria break off and establish new infections – and new biofilms—elsewhere. Unfortunately, it’s difficult to culture bacteria in biofilms, because culture swabs usually can’t reach bacteria protected within the slime.
Whether your dogs’ water bowls are harmful depends on what kinds of bacteria are embedded in the slime. Since you don’t know what they are, play it safe by scrubbing their water bowls with detergent daily. Don’t simply swish the bowls out with water and refill them.
Besides, dogs prefer the taste of water from clean bowls.
Lee Pickett, V.M.D. practices companion animal medicine. Contact her at firstname.lastname@example.org.