THURSDAY, Dec. 13 (HealthDay News) -- In the ongoing battle to
control in-hospital bacterial infections, Dutch researchers think
they may have come up with a secret weapon: a dog named Cliff.
Turns out that, when properly trained, a dog's highly honed and
superior sense of smell can be effectively harnessed to sniff out
early signs of a common but problematic infection known as
Clostridium difficile, or
Exhibit A: Cliff, a 2-year old beagle who has already
demonstrated a remarkable ability to diagnose infections simply by
nosing around patients and their stool samples.
C. difficilecan cause an infection of the bowel, ranging
from mild symptoms of diarrhea to severe illness," explained study
author Dr. Marije Bomers, an internist at the VU University Medical
Centre, in Amsterdam. "The bacterium mostly affects older patients
in a hospital or health care facility after the use of antibiotics,
since antibiotics disturb the normal balance of bacteria present in
"Once a patient has a
C. difficilebowel infection, the infection can spread to
other patients on the same ward," Bomers noted, stressing the
importance of prompt identification followed by patient quarantine
to prevent spread. "However, in reality it can take a couple of
days before a
C. difficileinfection is identified, allowing the bacteria
to spread and infect more patients."
In the Dec. 13 online edition of the journal
BMJ, Bomers's team reported on its unconventional new
"In this research project we've trained a beagle called Cliff to
identify the smell of
C. difficileand subsequently tested its skills," she said.
"It turned out that [spotting infections] was not that difficult
for the dog."
Since 2000, infection outbreaks -- particularly in the United
States and Canada -- have grown in frequency and size, often
prompting the wholesale closure of hospital wings, the authors
noted. As a result, there has been an increased interest in the
development of faster, more accurate and affordable
The Dutch team spent two months using a reward-based training
system to teach Cliff to pick up the unique odor of
C. difficile, both in stool samples and among patients
After he learned to sit or lie down whenever the telltale scent
was unearthed, the authors tested the dog's talents on stool-sample
identifications in a microbiology laboratory setting. The result: a
nearly perfect diagnostic record.
Between 2010 and 2011, Cliff was repeatedly guided through
hospital wards in two Dutch facilities that were caring for a total
of 300 patients, 30 of whom were infected with
C. difficile. The guides were not told which patients were
infected, and Cliff made no direct contact with any patients -- he
simply sniffed the air surrounding their beds before rendering his
After 10 such "detection rounds," Cliff was successful in
C. difficilepatients 83 percent of the time.
"The bottom line is, it is very feasible to train a detection
dog to identify a superbug like
C. difficile," Bomers concluded.
While pointing to ongoing research exploring the ability of dogs
to sniff out different types of cancer, Bomers cautioned that their
usefulness at sniffing out other infections and diseases remains an
open question. But she suggested that dogs might ultimately help to
reduce the onset of
C. difficileby serving as routine "pet scans" that catch the
first sign of an infection and halt an outbreak in its tracks.
"The idea holds great potential," she said, "but more research
has to be done first to see whether this concept actually
Dr. Philip Tierno director of clinical microbiology and
immunology at New York University Langone Medical Center in New
York City, confirmed that dogs are already used for other types of
diagnostic ventures, and that setting them on the hunt for
C. difficileinfections "makes eminent sense."
"This organism has a characteristic odor, which can be smelled
by any medical personnel that's familiar with it," he explained.
"For a lack of a better word, I would describe it as a barnyard
odor, much like horse manure. It's very characteristic."
"We currently use dogs to smell out bed bugs, which give off a
smell when they cluster that can be detected by a dog but not by a
human," Tierno noted.
He added that he has noticed
C. difficilescent in samples from patients with "overt
medical manifestation of infection. But as our ability in terms of
scent is nowhere near that of a dog, there's no doubt in my mind
that it makes sense to use an animal for this purpose."
For more on in-hospital infections, visit the
U.S. National Library of Medicine.