ObjectiveTo analyze the effects of alcohol consumption on oral flora of middle-aged and elderly men from the core area of southwestern China, and explore the relationship between excessive-alcohol-consumption-related flora and alcohol-related cancer.MethodsFrom March to June 2018, saliva samples of target subjects were collected for 16S ribosomal RNA gene sequencing, and a questionnaire survey which took drinking history of each participant as the target variable was conducted. According to the amount of alcohol consumed, the subjects were divided into non-drinking group, moderate-drinking group, and excessive-drinking group. The microbial analysis of α diversity, analysis of group difference of oral flora abundance, bacterial function prediction, and receiver operating characteristic (ROC) curve model prediction were carried out.ResultsA total of 59 subjects were included. There were 23 cases (39.0%) in the non-drinking group, 23 cases (39.0%) in the moderate-drinking group, and 13 cases (22.0%) in the excessive-drinking group. The average age was (61.90±8.85) years. Excessive drinking increased the abundance of oral flora (P<0.05), and could change the abundance of specific genus such as Peptostreptococcus and TM7［G-6］ (P<0.05) and regulate cancer-related pathways (P<0.05). ROC analysis found that a panel of three genus oral bacteria such as TM7［G-6］ might effectively distinguish the non-drinking group from the excessive-drinking group (area under curve=0.915).ConclusionsGenus of Peptostreptococcus and TM7_［G-6］ are the potential oral flora biomarkers for the excessive-drinking of target subjects. Some excessive drinking-related flora are closely related to oral cancer.
ObjectiveTo systematically evaluate the composition spectrum of oral microbiota diversity in patients with head and neck tumors undergoing radiotherapy. MethodsComputer searches were conducted on CNKI, CBM, WanFang Data, PubMed, Embase, and Web of Science databases to collect cohort and control studies on changes in oral microbiota in patients with head and neck tumors after radiotherapy. The search period was from January 1, 2015 to June 1, 2025. Two researchers screened and evaluated literature, extracted data, and conducted meta-analysis using RevMan 5.4 software. ResultsA total of 25 studies were included, including 731 patients with head and neck tumors and 275 healthy controls. The meta-analysis results indicated that compared with the control group not exposed to radiotherapy, the detection rates of major oral opportunistic pathogens such as Candida albicans and Streptococcus mutans had significantly increased (OR=3.62, 95%CI 2.23 to 5.89, P<0.01). The Shannon index and Chao1 index for oral alpha diversity had decreased after radiotherapy (SMD=?0.78, 95%CI ?1.23 to 0.34, P<0.01; SMD=?0.64, 95%CI ?1.14 to ?0.15, P<0.001), and the differences were statistically significant. Qualitative analysis showed that after radiotherapy, the relative abundance of Firmicutes, Streptococcus, Lactobacillus, etc. in patients increased, while the relative abundance of Clostridium, Neisseria, etc. decreased. ConclusionThere are changes in the oral microbiota of patients with head and neck tumors after radiotherapy, mainly manifested as an increase in the detection rate of opportunistic pathogens, a decrease in alpha diversity, and an imbalance in the relative abundance of some bacterial phyla. This suggests that oral care should be taken seriously for radiotherapy patients.