Characterization of Bacillus pumilus Strains Isolated from Bovine Uteri

SIMPLE SUMMARY: Bound with proper productivity, reproductive performance in dairy cows is of utmost importance. One of the most important conditions hampering the reproductive performance of a dairy cow is bovine endometritis. In this paper, we aim to report the effect of B. pumilus strains, isolated from cows with or without endometritis, with regard to their pathogenicity to the bovine uterus by using a cell-culture-based approach. Our study revealed that B. pumilus strains possess specific genes related to enzyme production and harm the endometrial bovine cells in a dose-dependent pattern. ABSTRACT: Uterine infections are a major source of economic losses to dairy farmers. The uterine microbiota as well as opportunistic uterine contaminants can contribute to the development of endometritis in dairy cows during the postpartum period. Therefore, it is important to characterize potential pathogens and to further elucidate their role in the disease. In this study, we aimed to characterize Bacillus pumilus field isolates to obtain more details regarding their effect on uterine cells by using an in vitro endometrial epithelial primary cells model. We found that B. pumilus isolates possessed the keratinase genes ker1 and ker2 and therefore may produce keratinases. When primary endometrial epithelial cells were infected with 4 different B. pumilus strains, an effect on cellular viability was observed over the course of 72 h. The effect was dose-dependent and time-dependent. Nevertheless, significant differences between the strains were not observed. All tested strains reduced the viability of the primary cells after 72 h of incubation, indicating that B. pumilus potentially has a pathogenic effect on endometrial epithelial cells.