Revealing oral microbiota composition and functionality associated with heavy cigarette smoking.

Abstract

Background: Heavy tobacco smoking, a hallmark feature of lung cancer, is drastically predominant in Middle Eastern populations. The precise links between nicotine dependence and the functional contribution of the oral microbiota remain unknown in these populations.Methods: We evaluated the composition and functional capabilities of oral microbiota with relation to cigarette smoking in 105 adults through shotgun metagenomics using buccal swabs. Results: The oral microbiota composition in our study subjects was dominated by the phyla Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes, in addition to the genera Prevotella and Veillonella, similar to previously described westernized cohorts. Furthermore, the smoker's oral microbiota represented a significant abundance of Veillonella dispar, Leptotrichia spp., and Prevotella pleuritidis when compared to non-smokers. Within the smoking groups, differential relative abundance testing unveiled relative abundance of Streptobacillus hongkongensis, Fusobacterium massiliense, Prevotella bivia in high nicotine dependent compared to low nicotine dependent profiles based on Fagerström Test for Nicotine Dependence. Functional profiling showed marked differences between smokers and non-smokers. Smokers exhibited an enrichment of Tricarballylate utilization and Lactate racemization when compared to the non-smokers. According to their nicotine dependence, enrichment of Xanthosine utilization, p-Aminobenzoyl-Glutamate utilization, and multidrug efflux pump in Campylobacter jejuni biosynthesis modules were detected in the high nicotine dependent group. Conclusions: These compositional and functional differences may provide critical insight on how variations in the oral microbiota could predispose to respiratory illnesses and smoke cessation relapse in cigarette smokers. In particular, the observed enrichment of Fusobacterium and Prevotella in the oral microbiota possibly suggests an intriguing linkage to gut and lung cancers.

Changes in the Oropharyngeal Microbiome in Moderate-to-Severe Tobacco Dependence Before and After 30 Days of Smoking Cessation

“…In a previous study, the bacterial composition of seven different surface samples in the oral cavity was evaluated; similar microbial communities were observed in the buccal mucosa, gingiva, and hard palate; however, different microbial communities were observed in the saliva, tongue, tonsils, throat, and above and below the gingiva [22] . Mohammad et al [10] conducted 16S rRNA sequencing using oropharyngeal swab samples and reported that the oral microbiota composition is primarily represented by the phyla Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria in smokers. Furthermore, they identi ed the genera Prevotella and Veillonella [10] .…”

“…Mohammad et al [10] conducted 16S rRNA sequencing using oropharyngeal swab samples and reported that the oral microbiota composition is primarily represented by the phyla Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria in smokers. Furthermore, they identi ed the genera Prevotella and Veillonella [10] . These ndings are highly consistent with those of the present study; however, because the primary focus of the study was on the population in the Middle East, which exhibits obvious differences in ethnicity and dietary habits compared with our population, and different microbial gene sequencing methods were utilized, we observed variations in the classi cation at the microbial species level.…”

“…Imbalance in the oral micro ora can lead to various oral diseases, including dental caries, periodontitis, pulpitis, alveolar osteitis, and tonsillitis [3] ; this phenomenon is also associated with other systemic diseases, including infectious pulmonary diseases, infective endocarditis, stroke, preterm birth, diabetes, head and neck tumors, and gastrointestinal tumors [4][5][6][7][8][9] . Smoking, dietary habits, alcohol drinking, and oral hygiene encompass some of the factors that affect the structure of the oral microbiota [10] . Among them, smoking is considered an important factor affecting oral microbiota composition.…”