Risk factors and intestinal microbiota: Clostridioides difficile infection in patients receiving enteral nutrition at Intensive Care Units.

BACKGROUND: Clostridioides difficile infection (CDI) is a leading cause of nosocomial diarrhea. Patients receiving enteral nutrition (EN) in the intensive care unit (ICU) are potentially at high risk of CDI. In the present study, we assessed the risk factors and intestinal microbiome of patients to better understand the occurrence and development of CDI. METHODS: Patients were screened for C. difficile every week after starting EN, and their clinical records were collected for risk factor identification. Fecal samples were analyzed using 16S rRNA sequencing to evaluate the intestinal microbiota. RESULTS: Overall incidence of CDI was 10.7% (18/168 patients). History of cerebral infarction was significantly associated with CDI occurrence (OR, 9.759; 95% CI, 2.140-44.498), and treatment with metronidazole was identified to be protective (OR, 0.287; 95% CI, 0.091-0.902). Patients with EN had lower bacterial richness and diversity, accompanied by a remarkable decrease in the abundance of Bacteroides, Prevotella_9, Ruminococcaceae, and Lachnospiraceae. Of these patients, acquisition of C. difficile resulted in a transient increase in microbial diversity, along with consistent alterations in the proportion of some bacterial taxa, especially Ruminococcaceae and Lachnospiraceae. Upon initiation of EN, patients who were positive for C. difficile later showed an enhanced load of Bacteroides, which was negatively correlated with the abundance of C. difficile when CDI developed. CONCLUSION: ICU patients receiving EN have a high prevalence of CDI and a fragile intestinal microbial environment. History of cerebral infarction and prior treatment with metronidazole are considered as vital risk and protective factors, respectively. We propose that the emergence of CDI could cause a protective alteration of the intestinal microbiota. Additionally, Bacteroides loads seem to be closely related to the occurrence and development of CDI.