Sensitivity of dairy calf serotype Cerro isolates to infection-relevant stressors.

serotype Cerro (. Cerro) is an emerging serotype isolated from cattle, but the association of . Cerro with disease is not well understood. While comparative genomic analyses of bovine . Cerro isolates have indicated mutations in elements associated with virulence, the correlation of . Cerro fecal shedding with clinical disease in cattle varies between epidemiologic studies. The primary objective of this study was to characterize the infection-relevant phenotypes of . Cerro fecal isolates obtained from neonatal calves born on a dairy farm in Wisconsin, USA. The . Cerro isolates varied in biofilm production and sensitivity to the bile salt deoxycholate. All . Cerro isolates were sensitive to sodium hypochlorite, hydrogen peroxide, and acidic shock. However, . Cerro isolates were resistant to nitric oxide stress. Two . Cerro isolates were unable to compete with . Typhimurium during infection of calf ligated intestinal loops, indicating decreased fitness . Together, our data suggest that . Cerro is sensitive to some innate antimicrobial defenses present in the gut, many of which are also used to control in the environment. The observed phenotypic variation in . Cerro isolates from a single farm suggest phenotypic plasticity that could impact infectious potential, transmission, and persistence on a farm.IMPORTANCE is a zoonotic pathogen that threatens both human and animal health. serotype Cerro is being isolated from cattle at increasing frequency over the past two decades; however, its association with clinical disease is unclear. The goal of this study was to characterize infection-relevant phenotypes of . Cerro isolates obtained from dairy calves from a single farm. Our work shows that there can be variation among temporally related . Cerro isolates and that these isolates are sensitive to killing by toxic compounds of the innate immune system and those used for environmental control of . This work contributes to our understanding of the pathogenic potential of the emerging pathogen . Cerro.