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This award-winning blog supplements the articles in Hospital Infection Control & Prevention.

The Malodorous Malady: C. Difficile ‘Ranks’ as Most Common Hospital Infection

In the lore and legend of infectious diseases there is the persistent belief by some experienced nurses that they can identify Clostridium difficile by its distinctive smell in the patient’s stool. If so, we invite them to step outside and take a whiff, because, to paraphrase the Bard, something is rotten in Denmark and it stinketh to high heaven.

While CRE and other “superbugs” have been much in the news of late, a nasty sewer rat of a pathogen has quietly become one of the leading infectious disease killers in the country. Clostridium difficile -- or “deadly diarrhea” as the CDC dubs it – causes almost a half a million infections annually in the U.S., resulting in 15,000 deaths that are directly attributable to C. diff, the Centers for Disease Control and Prevention reports.1

In fact, C. diff -- a spore-forming bacillus that is notoriously difficult to remove by hand washing -- has become the most common microbial cause of health care associated infections (HAIs) in U.S. hospitals, the CDC notes. Most of the burden of disease is striking the elderly, with about 65% of health care associated C. diff infections and 80% of the deaths occurring in people at age 65 or older.

“One out of nine patients over 65 years old with health care associated C. difficile infections dies within 30 days of diagnosis – that is a frightening statistic,” Michael Bell, MD, deputy director of CDC’s Division of Healthcare Quality Promotion said at recent press conference. The study was done at 10 sites in the CDC’s Emerging Infections Program (EIP), meaning the 2011 data reflect a broad geographic distribution.

A confluence of events has led to an epidemic of C. diff, including the emergence of the highly virulent NAP1 strain, the misuse and overuse of antibiotics, and the difficulty of removing it from health care worker hands and contaminated surfaces.

“Because [alcohol] hand sanitizers don't kill spores, it's essential that you thoroughly wash your hands with soap and water to remove them,” Bell said. “This is one reason why we recommend glove use when caring for patients with C. difficile -- to make it easier to maintain good hand hygiene. There's no room for error.”

While the sequelae of any HAI can have some horrific presentations, it’s hard to imagine anything much worse than the NAP1 strain’s ability to spur life-threatening diarrhea and toxic damage to the colon.

“In the past, patients infected with C. difficile have had diarrhea that was often perceived as a nuisance but not a major problem,” Bell said. “Unfortunately the type of C. diff circulating in the U.S. today produces such a powerful toxin that it can cause a truly deadly diarrhea – [an] intense illness that can include damage to the bowels so painful and severe that part of the colon needs to be surgically removed, a condition called toxic megacolon."

Patients on a course of broad-spectrum antibiotics are at risk for developing C. diff infections, as the drugs can wipe out commensal bacteria in the gut and leave the patient vulnerable to infection if C. diff is spread from an environmental surface or from another patient via the hands of health care workers. More than half of all hospitalized patients will get an antibiotic at some point during their hospital stay, but the CDC estimates that 30% to 50% percent of antibiotics prescribed in hospitals are unnecessary. Antibiotic misuse and poor infection control may increase the spread of C. difficile within a facility and from facility to facility when infected patients transfer, such as from a hospital to a nursing home.

“Although people receiving care in hospitals made up two-thirds of all [C. diff] infections, two-thirds of those actually occurred after the patient went home,” Bell said. “It's essential that patients and their clinicians be aware that they need to take any diarrhea following antibiotic use very seriously. “

Other than reducing unnecessary antibiotic use – a tremendous challenge in its own right – the other main intervention is to improve infection control in health care facilities.

C-difficile infections must be diagnosed quickly and correctly so that the infected patient can be cared for using the right infection control techniques, cleaning the environment near the patient with the right spore-killing disinfectants, ensuring perfect hand hygiene all the time and also letting facilities know when a patient with C-difficile is about to be transferred to them so they can use the right infection control practices,” Bell said.

And, given the stakes, it might be worth it to follow a wily nurse’s olfactory suspicions with confirmatory testing.


1. Lessa FC, Bamberg WM, Beldavs ZG, et al. Burden of Clostridium difficile Infection in the United States. N Engl J Med 2015; 372:825-834