Determining the expected microbial flora of a body site is an initial step toward determining whether unexpected microbial presence or community composition is associated with disease. Unfortunately, culture methods have failed to reveal the bulk of microbial communities and the analyses previously performed using culture must be revisited with molecular methods.
We enrolled 10 women into our pilot study. Eligible participants undergoing total hysterectomy with bilateral salpingo-oophorectomy had vaginal swabs and segments of the resected cervix, uterus, fallopian tubes, and ovaries sent for characterization of the microbiome community with exploratory quantitative polymerase chain reaction and DNA amplicon sequencing (using 454 platform).
The majority of samples exhibited significant bacterial colonization and approximately 50% had detectable fungal colonization as well (median 3,764 reads, minimum 852 reads in each positive sample). Bacteria were detected in 90% of samples. The remaining 10% were not from any particular anatomical location and resisted attempts at bacterial DNA sequencing. The upper reproductive tract flora was distinct from the lower with the vaginal flora colonized at high relative abundance by Lactobacilli, Prevotella, and Streptococci. In the upper reproductive tract, Chlamydiales and Nostocales were nearly ubiquitous and abundant while hardly present in the vaginal swabs.
Our study is the first evaluation of the microbiota of the female reproductive tract in its entirety. We demonstrated recovery of microbiota from sites that were previously considered normally sterile. The results of this trial will serve as the basis for future work correlating the colonization of the female reproductive tract with both obstetric and gynecologic conditions.