As I mentioned the other day, I took a fecal samples from Merlin, our new puppy, to see what I’d find and show how you have to be careful with interpreting diagnostic test results. In addition to an unconcerning (for me) amount of clostridial bacteria in a fecal smear, Campylobacter was also isolated on bacterial culture. It’s important to note that Merlin has not developed any diarrhea this whole time.
Interpreting Campylobacter results can be tough. This bacterium is an important cause of diarrhea in dogs and people, and contact with puppies is a known risk factor for human infection. So, should I be concerned for Merlin or the rest of the family?
The answer in this situation is no.
Why? All Campylobacter are not created alike. There are two main groups of Campylobacter: catalase-positive and catalase-negative. Catalase-positive species, most notably C. jejuni and C. coli, are the main concern in both animals and people. Catalase-negative species tend to be of little to no concern and are very common. We isolated a catalase-negative species from Merlin, one that’s not been associated with disease in dogs or people.
Understanding test results and ensuring that testing makes sense is critical. If a lab just reports "Campylobacter positive" as is the case with some (especially labs that just offer PCR (molecular) testing), I wouldn’t know what to think of the result. I need to know the species, or at least catalase-positive vs catalase-negative, to put the results into context and come up with a plan. In this case, the plan is to do nothing (or at least nothing we weren’t doing already).
More information about Campylobacter in pets is available on the Worms & Germs Resources page.