Exposure to industrial hog and poultry operations and urinary tractinfections in North Carolina, USA

An increasing share of urinary tract infections (UTIs) are caused by extraintestinal pathogenicEscherichia coli(ExPEC)lineages that have also been identified in poultry and hogs with high genetic similarity to human clinical isolates. Weinvestigated industrial food animal production as a source of uropathogen transmission by examining relationships ofhog and poultry density with emergency department (ED) visits for UTIs in North Carolina (NC). ED visits for UTI in2016-2019 were identified by ICD-10 code from NC's ZIP code-level syndromic surveillance system and livestockcounts were obtained from permit data and aerial imagery. We calculated separate hog and poultry spatial densities(animals/km2) by Census block with a 5 km buffer on the block perimeter and weighted by block population to esti-mate mean ZIP code densities. Associations between livestock density and UTI incidence were estimated using areparameterized Besag-York-Mollie (BYM2) model with ZIP code population offsets to account for spatial autocorrela-tion. We excluded metropolitan and offshore ZIP codes and assessed effect measure modification by calendar year, ZIPcode rurality, and patient sex, age, race/ethnicity, and health insurance status. In single-animal models, hog exposurewas associated with increased UTI incidence (rate ratio [RR]: 1.21, 95 % CI: 1.07-1.37 in the highest hog-densitytertile), but poultry exposure was associated with reduced UTI rates (RR: 0.86, 95 % CI: 0.81-0.91). However, the ref-erence group for single-animal poultry models included ZIP codes with only hogs, which had some of the highest UTIrates; when compared with ZIP codes without any hogs or poultry, there was no association between poultry exposureand UTI incidence. Hog exposure was associated with increased UTI incidence in areas that also had medium to highpoultry density, but not in areas with low poultry density, suggesting that intense hog production may contribute toincreased UTI incidence in neighboring communities.

Automated summary

Industrial food animal production may contribute to the transmission of urinary tract infections (UTIs). Exposure to hogs is associated with increased UTI incidence, while exposure to poultry is associated with reduced UTI rates.