Abstract 2831: Detection of methane-producing archaea in the cervix of Hispanics using shotgun metagenomics

Abstract

The human cervix is colonized by microbial communities that have traditionally been regarded as a protective barrier against infections. Dysbioses disrupting the balance of the normal microbiota, leads to the appearance of anaerobic taxa that have been related to sexual transmitted infections and cancer. The complexity of the diversity and composition of cervicovaginal communities has been recently highlighted by 16S rDNA surveys, although these have limitations to either select mostly bacteria and the lack of strong lower taxonomic resolution such as being species-specific. Metagenomic shotgun sequencing overcomes these limitations, and gives us access to the extent of diversity beyond bacterial communities. This is the first project to characterize the bacterial and archaeal communities of the cervix of Puerto Ricans using shotgun metagenomics. Women coming for gynecology and colposcopy evaluation at the UPR and San Juan City clinics (San Juan Metropolitan area), and who did not meet several excluding criteria including having taken antibiotics for the last month, were recruited for the study. Samples were acquired by inserting a speculum for access and visualization of the cervix and a sterile swab was rotated along the lumen with a circular motion and frozen immediately for posterior genomic DNA extractions and sequencing. Library construction and shotgun sequencing of 10 cervical patient samples was done with the Illumina HiSeq platform An average of 1,690,000 good quality reads per sample were analyzed. Approximately 90% of the contigs had more than 1,000bp and 10% had sizes ranging from 1,000-5,000bp. Microbial communities were dominated by Lactobacillus, including L. iners, Gardnerella vaginallis, Nocardia and Atapobium vaginae. Archaeal diversity was dominated by Methanosarcina (namely, M. barkeri) with other less dominant taxa such as Methanolobus, Methanococcus, Natrococcus and Methanobrevibacter. The dominance of Lactobacillus was expected, and as Archaea are environmental organisms that have been associated with the mucosa in mammals, including protecting the human gut, they must have an important role in the cervix. As methanogenic archaea are known to remove fermentation end products, such as methanol and ethanol, as end-products of other fermentative bacteria, methanogenesis maybe important in preventing the accumulation of gases and other reaction end products that could damage the cervical mucosa. Citation Format: Filipa Godoy-Vitorino, Frances Vazquez-Sanchez, Anelisse Dominicci-Maura, Josefina Romaguera. Detection of methane-producing archaea in the cervix of Hispanics using shotgun metagenomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2831.