Hospitals Finds Low Rates of Asymptomatic Toxigenic C difficile Carriage

A new report suggests relatively few people in hospitals are asymptomatic carriers of toxigenic Clostridioides difficile.

The study, based on screening of patients at 11 healthcare centers in France, offers new insights into the risks of C difficile infection (CDI) transmission within healthcare settings. The study was published in the journal Frontiers in Medicine.

Nearly half of all nosocomial gastrointestinal infections in European hospitals can be traced to C difficile, noted corresponding author Sarah Jolivet, MD, of the Saint Antoine Hospital, in Paris, and colleagues. In France, the incidence of CDI among hospitalized patients has been on the rise over the past 2 decades, the authors noted.

One of the reasons CDI can be hard to contain in healthcare settings is that some patients are unknowing carriers of toxigenic strains of C difficile. Just because they have no symptoms, though, does not mean patients are not a danger to others, Jolivet and colleagues said..

“A recent study showed that the environment of asymptomatic C difficile carriers is as contaminated as that of symptomatic CDI patients,” the authors wrote. “A quasi-experimental controlled study revealed that identification and isolation of C difficile carriers was associated with a decreased incidence of CDI.”

Despite such evidence, the investigators said routine screening for asymptomatic carriers is not currently a part of recommended infection control guidelines. To find out if it should be, they decided to screen patients at 11 Paris-area hospitals. The screenings were performed at the hospitals between September 2019 and January 2020. On a given day, all patients who had been hospitalized for more than 24 hours and who did not object to participating were screened for toxigenic C difficile and interviewed. Patients in psychiatric units were excluded.

A total of 2389 patients with a median age of 62 years were included in the final analysis. Of those, 48.3% were male, and 19 patients (0.9%) had previously experienced CDI.

The authors found that 185 patients (7.7%) tested positive for C difficile. Of those, 93 patients were positive for toxigenic strains (3.9% of the total). Most (82.8%) of those patients were asymptomatic (an overall prevalence of 3.2%).

The authors said those rates were lower than previous reports, including a separate multicenter report from France.

“This result may reflect differences in studied populations, or local epidemiology such as hospital outbreaks. It can also be explained by different microbiological techniques used to isolate C difficile,” Jolivet and colleagues wrote. “We used rectal swabbing and direct culture whereas others used stool samples and enriched culture.”

The investigators also found a notable difference when they examined groups by age. Children ages 3 and younger had a C difficile positivity rate of 22.4% and a toxigenic C difficile rate of 7.0%. Those higher rates were in line with previous studies, the authors said.

Among patients older than age 3, previous CDI and co-carriage of multidrug-resistant organisms were associated with an increased risk of asymptomatic toxigenic carriage of C difficile. On the other hand, patients who consumed raw milk products were less likely to be colonized, likely because milk-associated bacteria produce a barrier effect, the authors found.

Jolivet and colleagues said their results cannot necessarily be generalized, since only 55.7% of eligible patients were included and screened. They also noted that rectal swabbing is less sensitive than stool specimens.

Still, they said their study benefited from the inclusion of a large number of patients and a large number of hospitals, and from the fact that they did not limit their analysis to high-risk patients.