Characterization of pelvic and cervical microbiotas from patients with pelvic inflammatory disease

Purpose. The aims of this work were: (i) to profile and compare pelvic and cervical microbiota from patients with pelvic inflammatory disease (PID); (ii) to test the ascending infection hypothesis that the microbes in the vagina or cervix spread to the upper genital tract and cause PID. Methodology. Thirty-eight PID patients and 19 control patients were enrolled in this study and received salpingectomy or salpingo-oophorectomy. Both pelvic and cervical samples were collected during surgery, which were subject to culture diagnosis and next-generation sequencing (NGS)-based 16S rRNA profiling. Results. For the PID group, the NGS-based method revealed that half of the pelvic samples were dominated by a single organism while the other half exhibited a polymicrobial infection. The pelvic and cervical microbiota were similar in terms of both taxonomic richness and evenness. Pelvic microbiota was dominated by Acinetobacter, Escherichia, Sneathia and Streptococcus whereas cervical microbiota was dominated by Lactobacillus and Gardnerella. Only six pelvic samples were positive by culture diagnosis, three of which matched the NGS-based results. The PID group was further divided into 23 hydrosalpinx and 15 pyosalpinx samples according to the pelvic mass collected during surgery, the former showing a richer bacterial composition than the latter. Conclusion. The NGS-based method provides a more informative profile of pelvic microbiota than the culture method. The pelvic and cervical microbiota from the same patient were inconsistent with each other, and thus therapeutic decisions based on cervical microbiota may lead to antimicrobial misuse.