For decades, Clostridium difficile infection (CDI) was dismissed by doctors as “annoying but easy to treat” — a common but not especially threatening cause of diarrhoea and colon inflammation.
“An alarming increase in the incidence of CDI” has been reported worldwide, along with higher rates of recurrence.
Even more worrisome, new, more virulent strains of the bacteria have emerged, including ribotypes 027 and 078. Resistant to traditional antibiotics, these strains often cause painful abdominal cramping, fever, nausea, dehydration, and severe diarrhoea.
“These complications can be devastating for some patients and ultimately fatal for others,” report infection-control experts at Duke University in North Carolina. “C. difficile is a growing challenge globally and is threatening the safety and lives of our patients.”
In the United States, Canada, and Europe, CDI incidence increased by 2- to 4-fold in a decade and is particularly prevalent among elder patients with exposure to nursing homes and hospitals. Patients 65 years and older are at least 5 times more likely to develop CDI than younger patients.
In the United States alone, C. difficile causes nearly half a million infections annually. In a single year, 29,000 patients — 90% of them age 65 and older — died within 30 days of CDI diagnosis; 15,000 of the deaths were directly attributed to C. difficile infections. About 1 in 5 patients with a healthcare-associated C. difficile infection experienced a recurrence.
A Scottish study, echoing other research, found that 29% of all CDI patients died within two months of hospital admission, and infected patients were hospitalized on average 9.7 days longer than patients without CDI, incurring enormous costs.
These grim statistics have sparked new research on how CDI is spread and, critically, how infection can be prevented and contained.
Prevention efforts have long focused on hand hygiene, surface cleaning, and antibiotic stewardship — all critical strategies for hospitals and nursing homes. However recent research suggests the CDI epidemic warrants an additional line of defence: air disinfection.
“There is a clear risk for C. difficile contamination via the air, particularly in patients with active CDI symptoms,” British researchers concluded in Clinical Infectious Diseases.
C. difficile spores shed by these patients can be launched airborne when, for example, bedding is changed, curtains are drawn, or doors are opened. New technology can reduce airborne C. difficile by 99.6% within 20 minutes, dramatically lowering the number of harmful bacteria that can settle on surfaces and ultimately infect patients.
The “Fecal Cloud”: How C. Difficile Spreads
C. difficile is shed in faeces, so any surface — a nurse’s hands, a rectal thermometer, a door handle — that becomes contaminated with a CDI patient’s faeces can serve as a reservoir for these potent spores.
Patients’ clothing, bedding, and skin are often teeming with spores, as are the surfaces and equipment they come in contact with.
A single patient can become contaminated over multiple regions of the body — on the groin, chest, abdomen, forearms, and hands, according to a study conducted at an American military hospital. And C. difficile contamination often persists even after diarrhoea has resolved. As a result, the authors concluded, the bacteria “was easily acquired on investigators' hands.”
From there, health care workers can spread the bacteria either by direct contact with patients or by touching surfaces or medical equipment that vulnerable patients touch prior to touching their mouth.
What makes infection control especially challenging: C. difficile spores are resistant to most disinfectants and can survive on hard surfaces for as long as 5 months.
Infection-control experts have known for decades that C. difficile is easily transmitted via hands and surfaces, but only recently have they recognized airborne transmission of the bacteria.
A study conducted at the University of Leeds was the first to provide evidence that C. difficile spores float in the air surrounding CDI patients. The worse a patient’s diarrhoea, the more likely spores were detected in the surrounding air.
The Leeds scientists repeatedly tested 10 patients with symptomatic CDI over a 10-hour period. The air surrounding 7 of the patients tested positive for the bacteria, typically during visiting hours or times of heavy activity, such as food delivery, ward rounds, or bedding changes.
In addition, surfaces surrounding 9 of the 10 patients were contaminated. The scientists suspect all the movement — opening and closing doors, pulling sheets off the beds — stirred up spores that had settled on these surfaces, sending them into the air.
Inhaling these spores isn’t a danger; rather, patients become infected by swallowing the bacteria. However, airborne spores can linger in the air and land on surfaces, where they do pose a threat.
Read Part 2 of this blog post here.