Canine Detection of C diff Spores: A New Environmental Tool

The US Centers for Disease Control and Prevention (CDC) estimates that there are roughly half a million cases of Clostridioides difficile (C diff) every year in the United States. Unfortunately, 15,000 of those cases result in death, which makes C diff a serious infectious disease threat. In addition to morbidity and mortality, C diff has a strong relationship to antibiotic use and ultimately costs the US health care system nearly $5 billion each year.

One of the challenges we experience in infection prevention is often the rapid diagnosis and isolation of patients. Awareness goes beyond the isolation of infectious patients though, and expands to the ability to disinfect medical equipment and objects or surfaces that might be contaminated, and thus have the potential to transmit the diarrheal illness. C diff is especially challenging as it produces spores that are very environmentally hardy, which makes disinfection a hurdle. Normal cleaning products or even alcohol-based hand sanitizers are not effective against the spores, which means handwashing with soap and water and then disinfecting with bleach or a sporicidal is critical.

Outside of rooms and spaces that have been clearly identified as contaminated with C diff spores (i.e. a patient with an active infection has stayed in the space), it can be difficult to know where to properly disinfect with spore-killing measures. One particular approach though has gotten a lot of attention — C diff canine scent detection. That’s right, specially trained dogs are being used to sniff out this bug to help guide environmental cleaning efforts.

Vancouver Coastal Health is one place that’s leading the pack (literally and figuratively) in the use of C diff canine scent detection. A team recognized that 60% of cases are related to health care transmission and worked to develop a program to help train dogs to detect C diff with 97% accuracy.

Validated by the Scientific Working Group on Dog & Orthogonal Detection Guidelines (SWGDOG) and the National Detector Dog Manual, they note that “Since its inception in 2016, our canine detection teams have successfully searched hundreds of hospital areas for C diff. Each contamination alert is acted upon immediately and used as an opportunity for in-the-moment education for health care workers, cleaning staff and patients. Alert data is also used to design & implement targeted quality improvement initiatives.”

The team has trained 2 dogs (Angus and Dodger — who are handled by Teresa Zurberg and Elizabeth Bryce) and is working on getting more through the program, but they point out that not only does this enhance surveillance measures through cost-effective means, but the dogs increase staff engagement and have helped reduce environmental contamination through identifying areas that are contaminated with toxigenic strains and need disinfection.

While the dogs don’t go into surgical suites, food preparation areas, neonatal units, and psychiatric units, their training involved a double testing format and they do undergo routine veterinary check-ups. The team recently published an article on their work with Angus and Dodger- “Over an 18-month period, a research team that included Bryce and Zurberg found that, of 391 positive alerts from Angus and Dodger (out of 659 searches), 321 (82.1%) were in the general hospital environment, mainly on hallway items. More than half of the hits in the general environment (192/321, 59.8%) were on items almost exclusively handled by health care workers, such as carts, equipment that measures and monitors patient vital signs, and staff lockers. There were also alerts in areas shared by the public, including waiting rooms and public bathrooms.”

The use of canine scent detection for C diff has been talked around in the infection prevention community for years, however, publication of successful efforts shows that they have promise for future efforts. Identification of areas with C diff spores can be extremely difficult and costly, which means that there is ample opportunity to build robust programs for canine detection.