Investigation of the relationship of ectocervical microbiota with cervical preinvasive lesions and HPV infection

Cervical cancer is a significant global health issue that is predominantly caused by infection with the human papillomavirus (HPV). While there is evidence linking the cervico-vaginal microbiota to persistent HPV infection, research on women with pre-invasive cervical epithelial lesions is limited. The objective of this study was to analyze and compare the composition of cervical microbiota in patients who tested positive for HPV and had low- grade squamous intraepithelial lesions (LSIL) or high-grade squamous intraepithelial lesions (HSIL), with patients who tested negative for HPV and had negative results for both current smear tests with atypical squamous cells (ASCUS) and LSIL. The investigation was conducted on a sample of 42 female patients, who were examined for cervical microbiota. Metagenomic analysis was used to assess the composition of the microbiota in a group of 21 patients who tested positive for HPV and another group of 21 patients who tested negative for HPV. The Firmicutes phylum was the most commonly observed at the phylum level in both the HPV negative and HPV positive groups. The abundance of Firmicutes decreased while the abundance of Actinobacteria increased in the group of individuals who tested positive for HPV. Lactobacillus and Lactobacillus iners (CST III) was the predominant genus and species in both the HPV negative and HPV positive groups. Distinct variations were seen in at genus and species level between HPV positive and negative groıp. In HPV positive cases, at species level Prevotella copri and Atopobium vaginae in the HSIL group, Gemmiger formicilis, Veillonella dispar, Prevotella copri, and Faecalibacterium prausnitzii in the LSIL group, and Prevotella melaninogenica in the NSIL group, have been observed. We also observed differences at species level among the ASCUS, LSIL, and NSIL groups in HPV negative group. Based on the SIN status, the predominant species was Lactobacillus iners, 87.9% in the microbiota composition of LSIL patients. Parabacteroides at the genus level and Blautia obeum, Parabacteroides_s, and Peptostreptococcus_s at the species level were more abundant in HPV positive NSIL group. Paracoccus marcusii was more abundant in HPV negative NSIL group. The presence of Blautia obeum in HPV positive NSIL cases and Paracoccus marcusii in HPV negative cases in NSIL cases indicates that the microbiota composition differs based on HPV status in the same pathological condition. Displaying the prevalence of Blautia obeum, particularly in HPV positive patients, in larger groups would be beneficial.