Characterizing the vaginal microbiome in patients with high grade cervical dysplasia (277)

Abstract

Objectives: The influence of the vaginal microbiome on risk for cervical dysplasia and cancer is unknown. It is hypothesized that the microbiome can impact the infectivity of human papillomavirus, and some bacteria may even have pro-oncogenic effects. The impact of dysplasia and cancer treatment on the microbiome is also unknown. The objective of this study was to characterize the vaginal microbiome of patients with high-grade cervical dysplasia and determine whether microbiome phylotypes changed after the cervical loop electrosurgical excision procedure (LEEP). Methods: Pre-menopausal women undergoing LEEP for high-grade cervical dysplasia were recruited. Vaginal swabs were collected prior to the LEEP procedure and six weeks post-procedure. DNA was extracted, and the hypervariable V4 region of the bacterial and archaeal 16S rRNA gene was amplified and sequenced using Illumina next-generation sequencing. Sequenced reads were processed and quality-filtered using AdapterRemoval and clustered into operational taxonomic units (OTUs) using a closed-reference OTU-picking strategy implemented in QIIME. A 97% identity threshold was used, and taxonomy was assigned using the EZTaxon database. The resulting OTU table was rarefied to 10,000 sequences. Conclusions: Our findings are consistent with existing data demonstrating an association between an L. iners-dominant microbiome and severe cervical dysplasia. Additionally, a more diverse and less Lactobacillus-dominated vaginal microbiome has been shown to be more prevalent amongst HPV-positive women. In contrast to published data, our findings, while based on a small number of cases, did not demonstrate consistent alterations in vaginal microbiota after the LEEP procedure. We plan to collect more longitudinal data on the persistence and progression of dysplasia in association with vaginal microbiomes to better understand the relationship between these two entities. Objectives: The influence of the vaginal microbiome on risk for cervical dysplasia and cancer is unknown. It is hypothesized that the microbiome can impact the infectivity of human papillomavirus, and some bacteria may even have pro-oncogenic effects. The impact of dysplasia and cancer treatment on the microbiome is also unknown. The objective of this study was to characterize the vaginal microbiome of patients with high-grade cervical dysplasia and determine whether microbiome phylotypes changed after the cervical loop electrosurgical excision procedure (LEEP). Methods: Pre-menopausal women undergoing LEEP for high-grade cervical dysplasia were recruited. Vaginal swabs were collected prior to the LEEP procedure and six weeks post-procedure. DNA was extracted, and the hypervariable V4 region of the bacterial and archaeal 16S rRNA gene was amplified and sequenced using Illumina next-generation sequencing. Sequenced reads were processed and quality-filtered using AdapterRemoval and clustered into operational taxonomic units (OTUs) using a closed-reference OTU-picking strategy implemented in QIIME. A 97% identity threshold was used, and taxonomy was assigned using the EZTaxon database. The resulting OTU table was rarefied to 10,000 sequences. Conclusions: Our findings are consistent with existing data demonstrating an association between an L. iners-dominant microbiome and severe cervical dysplasia. Additionally, a more diverse and less Lactobacillus-dominated vaginal microbiome has been shown to be more prevalent amongst HPV-positive women. In contrast to published data, our findings, while based on a small number of cases, did not demonstrate consistent alterations in vaginal microbiota after the LEEP procedure. We plan to collect more longitudinal data on the persistence and progression of dysplasia in association with vaginal microbiomes to better understand the relationship between these two entities.