Medical staff invest substantial time and effort into safeguarding patients against hospital-acquired infections. Their arsenal includes measures like strict hand hygiene, isolation protocols, and thorough environmental disinfection. Yet, despite these rigorous practices, hospital-onset infections persist, with Clostridioides difficile (C. diff) being the most prevalent culprit, causing close to half a million infections annually in the United States.
A surprising revelation from a recent study published in Nature Medicine suggests that the burden of C. diff infections may not primarily stem from in-hospital transmission but rather from patient-related factors.
This study, led by Evan Snitkin, Ph.D., and Vincent Young, M.D., Ph.D., both affiliated with the University of Michigan Medical School’s Departments of Microbiology & Immunology and Internal Medicine/Infectious Diseases, alongside Mary Hayden, M.D. from Rush University Medical Center, capitalized on ongoing epidemiological research focused on hospital-acquired infections. This allowed them to scrutinize daily fecal samples from all intensive care unit patients at Rush University Medical Center over a nine-month period.
Arianna Miles-Jay, a postdoctoral fellow in Dr. Snitkin’s lab, meticulously analyzed over 1,100 patients included in the study, discovering that slightly more than 9% of them were colonized with C. diff. Using whole genome sequencing at the University of Michigan, they assessed 425 C. diff strains isolated from almost 4,000 fecal specimens, scrutinizing their genetic makeup to trace any potential transmission.
Remarkably, the genomic analysis unveiled minimal evidence of transmission between patients, indicating infrequent in-hospital acquisition. Surprisingly, only six genomically supported transmissions occurred throughout the study. Instead, individuals who were already colonized with C. diff were at a higher risk of transitioning to a full-fledged infection.
Snitkin pointed out, “Something occurred with these patients that we still don’t fully comprehend, triggering the transition from C. diff residing in the gut to the organism causing diarrhea and other complications associated with infection.”
However, this doesn’t undermine the significance of hospital infection prevention measures. The practices in place at the Rush ICU during the study period, which included high compliance with hand hygiene, routine disinfection protocols targeting C. diff, and single-patient rooms, likely contributed to the low transmission rate. The study underscores the importance of additional steps to identify colonized patients and implement preventive strategies.
But where does C. diff originate? Vincent Young elucidates, “They are quite ubiquitous.” C. diff produces highly resilient spores that can withstand environmental stresses, including exposure to oxygen and dehydration, rendering them impervious even to alcohol-based hand sanitizers. Interestingly, only about 5% of the general population outside healthcare settings harbors C. diff in their gut, where it typically remains dormant and asymptomatic.
The researchers stress the need to find ways to prevent patients from developing infections when exposed to factors such as tube feedings, antibiotics, and proton pump inhibitors, which render individuals more susceptible to severe C. diff infections causing intestinal damage or worse.
In their future endeavors, the team aims to further explore the use of AI models to predict patients at risk of C. diff infections and to identify those likely to be colonized, enabling more precise intervention strategies.
Snitkin concludes, “A substantial amount of resources are dedicated to further enhancing infection control and prevention measures. Nevertheless, there’s a growing consensus to reallocate some of these resources toward optimizing antibiotic use and identifying other triggers that lead patients carrying C. diff and other healthcare-related pathogens to develop severe infections.”
Other contributors to the study include Arianna Miles-Jay, Michael Y. Lin, Teppei Shimasaki, Michael Schoeny, Christine Fukuda, Thelma Dangana, Nicholas Moore, Sarah E. Sansom, Rachel D. Yelin, Pamela Bell, Krishna Rao, Micah Keidan, Alexandra Standke, and Christine Bassis.