Complex sentence: The uterus has been found to possess its own characteristic microbiome that differs significantly from the vaginal microbiome, the former more closely resembling the commensal bacteria found in the oral cavity.
Split into simpler sentences: The uterus has been found to possess its own characteristic microbiome that differs significantly from the vaginal microbiome. The microbiome of the uterus more closely resembles the commensal bacteria found in the oral cavity.