The vaginal microbiota, high-risk human papillomavirus infection, and cervical cytology: results from a population-based study

BACKGROUND: The relationship between the vaginal microbiota, high-risk human papillomavirus infection, and abnormal cervical cytology has not been well characterized. Our objective was to characterize the vaginal microbiota in a stratified random sample of women from a population-based study in Appalachia. METHODS: We analyzed a random sample of 308 women in the Community Access, Resources and Education: Project 3 study across 16 clinics in Ohio and West Virginia. Using Illumina MiSeq sequencing of 16S rRNA gene amplicons, we characterized the vaginal microbiota among (I) 109 women randomly chosen with abnormal cervical cytology (i.e., the majority were atypical squamous cells of undetermined significance (n=55) and low-grade squamous intraepithelial lesions (n=45) while n=6 were high-grade squamous intraepithelial lesions and n=3 were atypical glandular cells); (II) 110 high-risk human papillomavirus infection only without cytologic abnormality; and (III) 89 women from a stratified random sample without cytologic abnormalities (negative for intraepithelial lesion or malignancy or any human papillomavirus infection). Among the women with abnormal cervical cytology (n=109), 80 had human papillomavirus infection, the majority of which were positive for a high-risk type (n=61). RESULTS: Nearly all of the women were non-Hispanic White (94.5%), and the mean age was 26 (IQR=21–39) years. Women with abnormal cervical cytology or who were HPV+ were more likely to have a diverse vaginal microbiota characterized by higher Gardnerella vaginalis relative abundance, compared to women without cytologic abnormalities whose communities were more likely to be Lactobacillus spp. dominant (P<0.04). Women without cytologic abnormalities had a higher prevalence of L. iners dominated communities than women with abnormal cervical cytology and HR HPV+ respectively (P<0.04), and L. gasseri relative abundance was differentially greater among these women compared to women with abnormal cervical cytology or who were high-risk HPV+ (Linear discriminant analysis effect size =4.17; P=0.0009). After adjustment for age, white race, current smoking, and ≥2 male partners in the last year, however, we did not detect differences in the vaginal microbiota community states across the three outcome groups. CONCLUSIONS: Compared to women without cytologic abnormalities, the vaginal microbiota of women with abnormal cervical cytology or who were high-risk HPV+ were characterized by a diverse community with increased relative abundance of G. vaginalis and reduced relative abundance of L. gasseri. However, these differences were attenuated after adjustment for other factors. Further study and validation of these differences for prognostic use is warranted.