Development of the Urogenital Microbiota in Healthy Beagle Puppies: A Longitudinal Comparison with the Dam.

Characterizing the microbiota is essential to improve the understanding and management of urogenital disorders. Using 16S rDNA sequencing, this study investigated the urogenital microbiota, including urine, vaginal, and prostatic communities, in a litter of 10 healthy beagle puppies from 4 months of age until the completion of the first estrous cycle in females and 18 months in males. A further objective was to compare these microbial profiles with those of their dam. Significant differences were observed between urinary and genital microbiota in both sexes, evolving over time. Notably, in females, puberty and the first estrous cycle were associated with marked changes in the vaginal microbiota, outweighing individual variability. In contrast, urinary microbiota remained stable during female growth. In males, microbiota showed time-dependent and individual-specific progression, with distinct microbial communities identified in the urinary bladder and prostate. Shared genera between the dam and her offspring were observed, but inter-individual variability suggested a limited maternal influence. Further investigation is needed to clarify vertical transmission patterns. In conclusion, the urogenital microbiota of healthy dogs undergoes dynamic and distinct site-specific changes during early life.