C. difficile carriage rates increase with proximity to livestock farms

Last Updated: 2020-01-20

By Will Boggs MD

NEW YORK (Reuters Health) - Residence near a livestock farm is associated with an increased carriage rate of toxigenic Clostridioides difficile, a retrospective study suggests.

"Where your patients live matters," Dr. L. Silvia Munoz-Price from Medical College of Wisconsin, Milwaukee, Wisconsin told Reuters Health by email. "We live in an interconnected world with animals, farms, patients, pollution, etc. The epidemiology of C. difficile in the geographical area where your practice is located should be taken into consideration when assessing patients at risk for C. difficile."

Previous studies have investigated factors associated with C. difficile colonization at the time of hospitalization, but environmental exposures to potential sources of transmission have received little attention.

Dr. Munoz-Price's team evaluated the association of environmental factors with the likelihood of being colonized with C. difficile at hospital admission in their retrospective study of 3043 patients admitted to a teaching-affiliated hospital in Milwaukee.

Overall, 318 patients (10.4%) were colonized with C. difficile. More patients colonized with C. difficile (33.3%) than those not colonized (22.6%) had been hospitalized in the preceding six months, and there was a significant association between the number of comorbidities and C. difficile colonization at admission.

In multivariable analysis, among non-hematology-oncology patients, a history of hospitalization within the preceding six months was independently associated with 66% higher odds of being colonized at admission, female sex was independently associated with 60% higher odds of being colonized at admission, and increased distance between patient residence and the nearest livestock farm was independently associated with 32% lower odds of being colonized at admission, according to the online report in JAMA Network Open.

In contrast, among hematology-oncology patients, the only factor significantly associated with colonization at the time of admission was black race.

Residential distance to meat processing plants, farm raw materials, or sewage treatment was not significantly associated with the odds of being colonized with C. difficile.

"People are being exposed to C. difficile outside the hospital," Dr. Munoz-Price said. "Thus, C. difficile infections in the hospital might have their origins outside the hospital. It is not all hospital-acquired."

"This environmental association might be owing not only to higher exposure to C. difficile, but also to exposure to microbiome disruptors, such as antibiotics and pesticides in water runoff," the authors note. "Future studies should examine the association between C. difficile and livestock farms in other geographic areas and, if an association exists, identify the underlying mechanisms for this association."

SOURCE: http://bit.ly/38uVyBb JAMA Network Open, online January 10, 2020.