Objectives: This study aimed to assess the relative abundances of Methylobacterium species in oral fibro epithelial polyp (FEP) tissues of a cohort of male patients and evaluate associations with their life style risk habits.

Materials and Methods: The sample comprised 25 histologically confirmed oral FEP tissues of male patients attended selected Oral & Maxillofacial Units (OMF) units across Sri Lanka. Amplification of nucle­otides of extracted DNA from frozen tissues was performed using degenerate primers for the V1 to V3 region of the 16S r RNA gene and sequencing of the amplicon with Illumina’s 2X 300–bp chemistry. Standard methodologies were used for sequencing, data processing and taxonomy assignment upto species level. Comparisons were made on percent average relative abundances of given Methylobacterium species by betel quid chewing, smoking and alcohol consumption habits using Fisher’s exact test.

Results: The percent average relative abundances of Methylobacterium sp. Oral Taxon C7, Methylobacterium sp. Oral Taxon B84 and Methylobacterium hispanicum of oral FEP tissues were 0.06%, 0.03% and 0.01% respectively. Significant differences were not evident in occurrence of given Methylobacterium species by betel quid chewing, smoking, and alcohol consumption habits categorized as never, past and current (p>0.05).

Conclusions:  Our preliminary findings established and quantified Methylobacterium sp. Oral Taxon C7, Methylobacterium sp. Oral Taxon B84 and Methylobacterium hispanicum in oral FEP tissues of male patients. Despite less than 0.1% of relative abundances of given species which is common to many taxa of the oral microbiome, those findings provide novel insights into molecular detection and diversity of oral Methylobacterium. Nevertheless, given the limitations of the present study, further research is warranted with large sample sizes to generate more conclusive evidence on implications of Methylobacterium species for oral health and possible associations with life-style risk habits.