Dogs: more than just cute!

Angus, one of two “super sniffer” dogs trained to alert their handler when they detect C. difficile. Source: Vancouver Coastal Health

We’ve all seen (or heard of) drug-sniffing dogs, but what about bacteria-sniffing ones?

Since 2016, a team from Vancouver Coastal Health has been tweaking a program that trains dogs to alert their handlers when they detect the scent of C. difficile. Over an 18-month period, the two dogs (Angus and Dodger) that have been trained for this role have detected 391 areas at Vancouver General Hospital where this bacteria was found.

Clostridioides difficile, more commonly referred to by its shorthand C. difficile or simply C. diff, are the leading cause of nosocomial (or hospital-originating) infectious diarrhea. Formerly known as Clostridium difficile, the bacterium was renamed late last year to more accurately portray the genus it falls in.

Angus and Dodger were trained with scent training kits from the Scientific Working Group on Dog and Orthogonal detector Guidelines (SWGDOG), which allowed them to identify the distinct odour of C. difficile. Microorganisms smell due to the variety of volatile chemicals they produce in response to various external factors. In the specific case of C. difficile, it is often described as having a sickly sweet or particularly foul smell.

The symptoms of a C. difficile infection can range from mild abdominal cramping to life-threatening sepsis and inflammation of the colon. The full range of symptoms can be found here. Most cases occur after taking antibiotics, which may kill both the good and bad bacteria in your gut – these are known as your gut microbiota. 

Without your normal gut microbiota, C. difficile can take advantage of this “clean slate” and proliferate in your intestine, throwing off the balance of good and bad bacteria. Within a period of several days to a few weeks, infected patients will start to show symptoms – the most common being diarrhea. Ideally, somebody with symptoms of infection will have tests done by a doctor and undergo treatment if necessary.

The progression of infection and the post-infection considerations are shown below in this graphic published by the Centre for Disease Control:

The progression of a C. diff infection. Source: Centre for Disease Control

In a study published by the Canadian Journal of Infection Control, it was found that 82% of contaminated surfaces were found in common areas. These included washrooms, hallways, and waiting rooms. Even with the most stringent sanitization procedures, it was relatively easy to find in areas that are commonly overlooked! 

One of the areas that tested positive for C. difficile contamination was inside a toilet paper dispenser – something that I personally would never think to sanitize. 

While there’s still a lot of work that needs to be done before we can train dogs to safely detect all sorts of infectious bacteria, the developments of the canine scent detection program are notable steps in the right direction. 

For more information about canine scent detection of C. difficile in Vancouver-area hospitals, you can learn more here and through this page.