“Hospital infections are sort of all around us!” But where did Clostridioides difficile come from – and are we overdoing infection prevention?
Hospital staff spend a significant amount of time working to protect patients from acquiring infections. They employ various methods from hand hygiene to isolation rooms to rigorous environmental sanitation. Despite these efforts, hospital-onset infections still occur – the most common of which is caused by the bacterium Clostridioides difficile, or C. diff, the culprit of almost half a million infections in the U.S. each year.
A recent study published in Nature Medicine suggests that the burden of C. diff infection may be less a matter of hospital transmission and more a result of characteristics associated with the patients themselves. The study team, led by Evan Snitkin, Ph.D. and Vincent Young, M.D., Ph.D., leveraged ongoing epidemiological studies focused on hospital-acquired infections that enabled them to analyze daily fecal samples from every patient within the intensive care unit at Rush University Medical Center over a nine-month period.
Arianna Miles-Jay, analyzed the over 1,100 patients in the study, and found that a little over 9 % were colonized with C. difficile. She used whole genome sequencing at U-M of 425 C. diff strains isolated from nearly 4,000 fecal specimens and compared the strains to each other to analyze spread.
“By systematically culturing every patient, we thought we could understand how transmission was happening. The surprise was that, based on the genomics, there was very little transmission.” Essentially, there was very little evidence that the strains of C. diff from one patient to the next were the same, which would imply in-hospital acquisition. In fact, there were only six genomically supported transmissions over the study period. Instead, people who were already colonized were at greater risk of transitioning to infection.
“Something happened to these patients that we still don’t understand to trigger the transition from C. diff hanging out in the gut to the organism causing diarrhea and the other complications resulting from infection,” said Snitkin.
Hayden notes that this doesn’t mean hospital infection prevention measures are not needed. In fact, the measures in place in the Rush ICU at the time of the study – high rates of compliance with hand hygiene among healthcare personnel, routine environmental disinfection with an agent active against C. diff, and single patient rooms – were likely responsible for the low transmission rate. The current study highlights that more steps are needed to identify patients who are colonized and try to prevent infection in them.
“They are sort of all around us,” said Young. “C. diff creates spores, which are quite resistant to environmental stresses including exposure to oxygen and dehydration. For example, they are impervious to alcohol-based hand sanitizer.” However, only about 5 % of the population outside of a healthcare setting has C. diff in their gut – where it typically causes no issues.
“We need to figure out ways to prevent patients from developing an infection when we give them tube feedings, antibiotics, proton pump inhibitors – all things which predispose people to getting an actual infection with C. diff that causes damage to the intestines or worse,” said Young.
This article is based on a press release by the University of Michigan. You can find the original publication here.
Image source: krakenimages, Unsplash
