Differences in Listeria monocytogenes contamination of rural Ohio residences with and without livestock

To determine the contribution of on-site livestock to the environmental contamination of rural households with Listeria monocytogenes, a total of 1779 environmental and food samples were collected from 26 ruminant-farm households and 26 rural households in Ohio. L. monocytogenes isolates were identified and differentiated using sequence comparisons of the intragenic regions of inlB and inlC. L. monocytogenes was isolated from shoes, 9.6% (20/208); utility gloves, 5.4% (6/111); kitchen sinks, 1.5% (3/204); washing machines, 0.96% (2/204); food, 1.11% (7/631); and animal feces, 8.7% (9/104), over the course of four household visits at monthly intervals. Notably, L. monocytogenes-contaminated shoes were identified more frequently from ruminant farmhouses than from rural households that did not raise ruminants on site (odds ratio = 4.8). L. monocytogenes isolated from animal feces was indistinguishable from strains recovered from shoes and gloves stored in several homes. Our results highlight the potential of the rural household environment as source of L. monocytogenes exposure.