Comparing the vaginal and endometrial microbiome in six subfertile women applying culturomics

Background
Culturomics is a high-throughput culturing approach that uses multiple culture conditions and matrix-assisted laser desorption/ionization-time of flight mass spectrophotometry (MALDI-TOF MS). We investigated to what extent the endometrial microbiome corresponds to that of the vagina with culturomics.
Materials and methods
Paired samples of endometrial biopsy and vaginal swab were simultaneously obtained from six subfertile women. For pre-incubation of these samples, an aerobic and anaerobic blood culture bottle with additives were used. After pre-incubation, seven different agar plates were on different days: 1, 5, 10 and 30. A WASPLab®-system was used to process the samples.
Results
A total of 3218 colonies were identified using the MALDI Biotyper® system enabling us to identify 79 different species. In five patients we found 14, 11, 18, 17 and 27 different species of which six (42.86%), four (36.36%), eight (44.44%), eight (47.71%) and seven (25.00%) were present in both vaginal and endometrial samples. These patients were colonized with Lactobacillus crispatus, Lactobacillus jensenii, Lactobacillus gasseri, Lactobacillus salivarius and/or Lactobacillus vaginalis. In the sixth patient, we found 49 different species, of which two (4.08%) were present in both vaginal and endometrial samples. This patient’s vagina was colonized with Lactobacillus iners and 43 other species like Gardneralla vaginalis and Candida albicans.
Conclusion
Our results suggest the existence of different endometrial and vaginal culturomics-microbiome profiles. In five patients, we observed eubiosis-related vaginal microbiome profiles, while a dysbiotic vaginal microbiome was observed in one patient. These findings seem associated with microbial diversity and presence of certain Lactobacillus species both at vaginal and endometrial level.