Most asymptomatic C. difficile carriers in health care settings did not progress to infection
In a study at three U.S. hospitals and affiliated long-term care facilities, most patients who were found to be carriers of Clostridioides difficile had cleared the bacteria on subsequent testing, and only 13.4% were subsequently diagnosed with infection.
Many patients who acquire asymptomatic Clostridioides difficile (C. diff) at health care facilities do not develop infection, a recent study found.
Researchers in Ohio and South Carolina performed a prospective cohort study in three hospitals and affiliated long-term care facilities between 2016 and 2018 to evaluate the natural history of C. difficile colonization and infection in these settings. Patients without diarrhea at study enrollment had serial perirectal cultures to identify new acquisition, duration, and burden of toxigenic C. difficile carriage. Asymptomatic carriage was defined as transient if only one culture was positive and cultures before and after were negative, and as persistent if two or more cultures were positive. Carriage was considered to be cleared if patients had two consecutive negative cultures. Patients with new detection of colonization had additional swabs collected monthly for up to six months to determine carriage duration, and all patients were followed for C. difficile diagnosis for three months after study enrollment. The study results were published March 11 by Clinical Infectious Diseases.
Overall, among 1,432 patients with negative initial cultures and at least one follow-up culture, 39 (2.7%) developed C. difficile infection without previous detection of carriage and 142 (9.9%) had asymptomatic carriage. In the latter group, 19 (13.4%) were subsequently diagnosed with C. difficile infection. Among 82 patients with enough data available for further analysis, 61.0% had transient carriage and 39.0% had persistent. The estimated median time to clearance of colonization was 77 days (range, 14 to 133 days). Persistent carriers were more likely to have a relatively high carriage burden than transient carriers (56.3% vs. 10.0%; P<0.001) and maintain the same ribotype over time; they were less likely to have a low burden of carriage that was detected only by using broth enrichment cultures (6.3% vs. 58.0%; P<0.001).
The researchers noted that the perirectal swabs were done weekly and that more frequent swabs would be needed to provide definitive information on C. difficile colonization and infection, among other limitations. “In conclusion, acquisition of asymptomatic carriage of toxigenic C. difficile carriage was common among patients in 3 healthcare facilities. However, most patients who acquired C. difficile developed transient rather than persistent carriage and only 13.4% were subsequently diagnosed with CDI,” they wrote. “Persistent carriers had a relatively high burden of carriage and might present a greater risk for transmission.”