Patients who occupy hospital beds in which the prior occupant received antibiotics may be more likely to develop Clostridium difficile infection (CDI), according to a study published yesterday in JAMA Internal Medicine.
While the increase in associated risk is small, the study's authors suggest the findings provide more evidence that antibiotic use in hospitals can increase host susceptibility to CDI—the most common cause of hospital-associated diarrhea—even when patients don't themselves directly receive antibiotics.
And that's another argument, they say, for the value of antibiotic stewardship.
More than 200,000 patients studied
The observational study, which was conducted at four hospitals in New York City, examined more than 100,000 pairs of patients who sequentially occupied a given hospital bed at one of the facilities from 2010 to 2015. Patients were excluded from the study if they developed CDI within 48 hours of admission, or if the prior hospital bed occupant was in the bed for less than 24 hours. The intent of the study was to determine whether antibiotic treatment in the initial bed occupant had any impact in CDI rates in subsequent patients.
Overall, there were 576 pairs in which the second hospital bed patient developed CDI within 2 to 14 days of admission—0.57% of the total number of patient pairs observed. The patients who developed CDI were more likely to have traditional CDI risk factors, such as older age, increased creatinine, and decreased albumin.
But the cumulative incidence of CDI was higher when the prior bed occupants had been treated with antibiotics (0.72%) than when they received no antibiotics (0.43%). In the final analysis, CDI was 22% more likely in patients who occupied a bed in which the prior occupant received an antibiotic.
In fact, when researchers considered other potential risk factors for CDI in the prior bed occupants—including treatment with acid-suppression medications and immune suppressants—antibiotic use was the only factor associated with increased risk for CDI in subsequent patients. And the association remained after the researchers excluded the patient pairs in which the prior patient had recent CDI.
Antibiotics add to colonization pressure
The findings add another layer to our knowledge of how antibiotics can increase susceptibility to CDI, which causes an estimated 500,000 illnesses and 27,000 deaths a year in the United States. It's already well established that treating patients with antibiotics increases risk for CDI by eliminating the good bacteria that keep C difficile in check or increasing bacteria that facilitate it. Previous studies have shown that antibiotic prescribing in individual hospital wards and in hospitals in general can also be associated with increased C difficile risk.
This study, though it only demonstrates a correlation, shows how antibiotics given to other patients may affect the local microenvironment and add to colonization pressure.
"In patients colonized by C difficile, antibiotics may promote C difficile proliferation and the number of C difficile spores that are shed into the local environment," the authors write. "In turn, this may result in a higher environmental burden of C difficile and greater risk for acquisition and infection in future patients who share the same environment."
Promoting C difficile proliferation and shedding is significant, the authors add, because C difficile spores can persist in hospital room surfaces for months and are easily transferred from patient to patient.
Because C difficile can spread so quickly and stronger strains are emerging, the Centers for Disease Control and Prevention have labeled the bacteria an urgent public health threat. The White House National Action Plan for Combating Antibiotic-Resistant Bacteria has set a goal of reducing CDI by 50% by the year 2020.
See also:
Oct 10 JAMA Intern Med study
