Analysis Of Saliva Microbial Community In Patients With Halitosis And Periodontitis

ObjectiveBad breath or bad breath refers to malodorous gas exhaled from the mouth.Bad breath can be caused by many sources,including sinuses,gastrointestinal tract,food ingested,lungs,and most commonly the oral cavity.Approximately 90%of oral odors are believed to come from malodorous gases produced by oral bacteria,such as volatile sulfur compounds(VSCs).The main components of VSCs in bad breath are hydrogen sulfide(H2S),methyl mercaptan(CH3SH)and dimethyl sulfide(CH3SCH3).Periodontitis is a chronic inflammatory disease and one of the most common oral diseases.The number of flora in the saliva of patients with periodontitis increases,the structure of the flora is complicated,and the formation of periodontal pockets and attachment loss provides more VSCs production site.In this study,by collecting the saliva of patients with periodontitis with or without bad breath,the difference in the composition of the microbial community was studied,and the relationship between bad breath and periodontitis was found.MethodsFrom September 2020 to January 2021,6 patients with moderate to severe chronic periodontitis with or without halitosis were randomly selected,and 3 healthy people were selected as controls,and they were divided into 3 groups:Group 1:3 patients with chronic periodontitis with halitosis;Group 2:3 people with chronic periodontitis without halitosis;Group 3:3 healthy people(control group),collected their saliva samples,and performed periodontal clinical index inspection records.The 16SrRNA coding genes were amplified by universal primers after the total DNA of microorganisms was extracted from the samples.The amplified products were sequenced and the obtained sequences were classified.Bioinformatics analysis was used to describe the composition characteristics of the salivary microbial community from the overall structure to the taxonomic level.Result1.After the analysis of saliva samples,770 kinds of OTOs were obtained,and the bacteria with high abundance were found to be Prevotella,Veronella,Bacteroidetes,Neisseria,Actinomycetes,Haemophilus,Streptococcus,Fusobacteria,etc.2.Through a diversity analysis,it was found that the microbial community diversity of group H,P and N was different.The microbial community diversity of group H was greater than that of group P and that of group N.3.The 3-diversity analysis showed that there was a significant difference between the groups.The differences between group H and P were significant,and the dominant bacteria in each group were also different.The dominant bacteria in group H were Fusobacteriota and Fusobacterium,while the dominant bacteria in group N was Haemophilus.Conclusion1.The diversity and structure of the salivary microbial community in the saliva samples with or without chronic periodontitis were different from those in the healthy people,and the dominant bacteria were also different.2.Halitosis will not cause significant changes in the diversity of the salivary microbial community,but it will lead to significant changes in the community structure.In this study,patients with periodontitis and halitosis detected a higher abundance of bacteria such as Fusobacterium,Neisseria,Porphyromonas,Tannerella,etc.The more abundant flora in the periodontitis without halitosis group includes Bacteroides,Actinomyces,Streptococcus,etc.The presence or absence of halitosis has a significant impact on the composition of the saliva microbial community in patients with periodontitis.;3.Periodontitis is closely related to halitosis,and periodontitis is a risk factor for halitosis.