Beagle Sniffs Out Bacterial Infection

Cliff the beagle has been trained to sniff out Clostridium difficile. (Image credit: BMJ)

Reported by Dr. Amish Patel:

A 2-year-old beagle in the Netherlands has been trained to sniff out Clostridium difficile, a skill that could help doctors catch the deadly infection days before laboratory tests.

Clostridium difficile infections often occur in people who are already taking antibiotics, causing symptoms that range from mild diarrhea to severe inflammation of the colon. And to make matters worse, the bug is particularly adept at spreading through hospitals, uncontrolled by the usual surface cleansers.

The clever canine, called Cliff, correctly identified 50 stool samples containing the bacterium, which kills 14,000 Americans each year, according to the U.S. Centers for Disease Control and Prevention. Cliff also identified 47 of 50 stool samples that were Clostridium difficile-free (he couldn't make up his mind about the last three).

Laboratory tests for Clostridium difficile - dubbed C. diff - can take up to 48 hours. But Cliff gives his answer immediately by sitting or lying down.

"The sooner the clinician has a diagnosis, the better it is," said Dr. William Schaffner, an expert in infectious diseases at Vanderbilt University Medical Center in Nashville, Tenn. "You can also reduce the risk of transmission to other patients."

Stool from patients with the C. diff has a characteristic smell, often likened to horse manure, which Cliff learned to identify over two months of training. Now he can smell the bug even without the stool, correctly identifying 25 of 30 patients with the infection and 265 of 270 without.

"We've always known that dogs make us feel good, but now we know that they're good for us," said veterinarian Dr. Marty Becker, who is based in Sandpoint, Idaho, and is the author of "The Healing Power of Pets" and a writer for

Dogs have also been trained to sniff out cancers of the lung, bowel, skin, breast, and bladder with high accuracy, and petting animals can also be therapeutic.

"We use them in our institution, largely in pediatrics, and have brought in reptiles, dogs and even miniature ponies," said Schaffner.

However, Cliff has struggled with staying focused at work, according to the study authors. A plastic cup, urine on the floor, excited children, and the strong smell of cleaners proved distracting.

"This may not work in the context of much more hectic U.S. hospitals," said Schaffner. "I don't think [dogs] will replace [existing laboratory tests]."

But Becker said the healing power of pets should not be underestimated.

"There was a time when you expected to see this kind of stuff in the tabloids," he said. "Now the science is there to show how it works. What are we going to find next?"