Association Between Environmental Factors and Toxigenic Clostridioides difficile Carriage at Hospital Admission

IMPORTANCE: Clostridioides difficile infection is the most frequent health care–associated infection in the United States. However, exposure to this organism might occur outside the health care setting. OBJECTIVE: To examine whether exposure to environmental factors, such as livestock farms, is associated with a higher probability of being colonized with C difficile at hospital admission. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study was conducted from May 1, 2017, to June 30, 2018, at a teaching-affiliated hospital in Milwaukee, Wisconsin. All consecutive patients underwent C difficile screening using a nucleic acid amplification test at hospital admission. Data analyses were performed from July 2018 to October 2019. EXPOSURES: The distances from patient residence to the nearest livestock farms, meat processing plants, raw materials services, and sewage facilities were measured in addition to risk factors previously evaluated in other studies. MAIN OUTCOMES AND MEASURES: The main outcome was a positive result on C difficile screening tests performed within 72 hours of hospital admission. RESULTS: A total of 3043 patients admitted to the hospital were included in the final analysis. Of those, 1564 (51.4%) were women and 2074 (68.9%) were white, with a mean (SD) age of 62.0 (15.9) years; 978 patients (32.1%) were admitted to hematology-oncology units. At first admission, 318 patients (10.4%) were detected through testing as C difficile carriers. Multivariable logistic regression analyses were performed on a stratified sample of patients based on hematology-oncology admission status. These analyses indicated that although patients admitted to hematology-oncology units were 35% more likely to be colonized with C difficile, no significant association existed between their sociodemographic and economic characteristics or health care and environmental exposures and the likelihood of a positive C difficile test result. In contrast, among patients admitted to non–hematology-oncology units, comorbidities increased the likelihood for colonization by more than 4 times; women had 60% greater colonization than men, and a history of recent hospitalization (ie, within the preceding 6 months) increased the likelihood of colonization by 70%. Residential proximity to livestock farms were all significantly associated with a higher likelihood of a positive C difficile test result. Residential proximity to livestock farms more than doubled the probability of C difficile colonization in patients admitted to non–hematology-oncology units. CONCLUSIONS AND RELEVANCE: A shorter distance between residence and livestock farms was associated with C difficile colonization. Knowledge of the epidemiology of C difficile in the community surrounding the hospital is important, as it has potential implications for the incidence of hospital-onset C difficile infection.