Deadly Hospital-Acquired C. difficile Infections Originate from Unexpected Source

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Deadly Hospital-Acquired C. difficile Infections Originate from Unexpected Source

Deadly Hospital-Acquired C. difficile Infections Originate from Unexpected Source: Patients Themselves

Clostridium difficile, a deadly bacterium often causing hospital-acquired infections, may not necessarily stem from external transmission but could be linked to the patients themselves.

Hospital staff go to great lengths to protect patients from infections during their hospital stays, implementing practices such as hand hygiene, isolation rooms, and stringent cleaning procedures.

Nevertheless, despite these measures, hospital-acquired infections, most commonly caused by Clostridium difficile (C. diff), continue to occur, responsible for nearly half a million infections in the United States each year.

Deadly Hospital-Acquired C. difficile Infections Originate from Unexpected Source

A surprising new study in *Nature Medicine* suggests that the burden of C. difficile infections may not be a result of nosocomial transmission but rather a consequence of patient-specific characteristics.

The research team, led by Dr. Evan Snitkin of the University of Michigan Medical School’s Department of Microbiology and Immunology and the Department of Internal Medicine/Infectious Diseases, along with Dr. Vincent Young and Dr. Mary Hayden of Rush University Medical Center, leveraged ongoing epidemiological research, focusing on hospital-acquired infections to analyze daily stool samples from every patient in the Rush University Medical Center intensive care unit over a nine-month period.

Dr. Arianna Miles-Jay, a postdoctoral researcher in Dr. Snitkin’s lab, analyzed data from over 1,100 patients in the study and found that slightly over 9% of patients were colonized with C. difficile. Using whole-genome sequencing of 425 strains of C. difficile isolated from nearly 4,000 stool samples at the University of Michigan, she compared these strains to analyze transmission patterns.

“By systematically culturing samples from each patient, we believed we could understand how transmission occurred. Surprisingly, based on genomics, the transmission rate was very low.”

Essentially, there was scant evidence to suggest that C. difficile strains in one patient were the same as those in another, indicating that transmission within the hospital was minimal. Instead, those who were already colonized had a higher risk of infection.

Dr. Snitkin explained, “Something we still don’t fully understand is happening in these patients that causes the C. difficile in their intestines to transition into a microbe that causes diarrhea and other infection complications.”

Dr. Hayden emphasized that this does not negate the need for hospital infection prevention measures. In fact, the measures implemented in the Rush ICU during the study, including high compliance with hand hygiene among healthcare workers, routine environmental disinfection with anti-C. difficile agents, and single-patient rooms, likely contributed to this situation. The current research underscores the necessity of identifying colonized patients and attempting to prevent their infections through additional measures.

Where does C. difficile come from? “It’s all around us. C. difficile produces spores that are highly resistant to environmental stress, including exposure to oxygen and dehydration… they are not affected by alcohol-based hand sanitizers.”

However, only about 5% of the non-healthcare population carries C. difficile in their intestines, and it typically doesn’t cause any problems.

“When we’re feeding patients through tubes, giving antibiotics, and proton pump inhibitors, we need to figure out ways to prevent infections in patients— all of these make people susceptible to C. difficile, leading to intestinal damage or worse,” said Dr. Young.

The team’s next steps involve continuing their work with artificial intelligence models to predict patients at risk of C. difficile infection, identify potential colonized patients, and benefit from more targeted interventions.

Dr. Snitkin concluded, “While a lot of resources have been invested in further improving the prevention of infection transmission, there is growing support for allocating some of these resources to optimize antibiotic use and identify other triggering factors that lead patients to carry C. difficile and other bacteria.”