Characterization of the cervicovaginal microbiota of female beef cattle harboring Campylobacter fetus subsp. venerealis using 16S rDNA gene sequencing.

Bovine Genital Campylobacteriosis (BGC) is a leading cause of return to estrus in cows. The etiologic agent, Campylobacter fetus subsp. venerealis (Cfv) is transmitted by venereal route. Hence, the surrounding reproductive tract microenvironment could play a role in return to estrus in cows. The presence of Cfv in cervicovaginal mucus of Angus breed females provide three experimental groups, which were subject to bacteriome analyses: 10 Cfv-positive cows (CVP), 10 Cfv-negative cows (CVN), and 10 non-sexually active heifers (NSA). Cows with return to estrus showed higher bacterial richness than non-sexually active heifers. Beta diversity analysis showed a significant difference (p = 0.006) in bacterial composition among the three groups analyzed (CVP, CVN, and NSA). However, no significant difference was found when comparing the CVP versus CVN groups. Ureaplasma and Pseudomonas were the genera most frequently observed in non-sexually active heifers, being Ureaplasma the predictor genus to that group, whereas Alistipes, Bacteroides, Rikenellaceae_RC9_gut_group, UCG-005, and UCG-10 were both, significantly more abundant and predictors genera, in cows with return to estrus. Our results provide an overview of the cervicovaginal bacterial microbiota in cows harboring Cfv and improve the knowledge of the pathogenesis of BGC.