Correlation between changes of oral bacterial flora and radiation-induced oral mucositis during radiotherapy for head and neck / 中华放射肿瘤学杂志

Objective:To investigate the correlation between the changes of oral bacterial flora during head and neck radiotherapy and radiation-induced oral mucositis (ROM).Methods:The oral bacterial samples of patients with nasopharyngeal carcinoma and accompanying family members were obtained before and at the end of radiotherapy and subjected to high-throughput sequencing. C57BL/6 mice were used to establish the ROM models. On the 9 th day after radiotherapy, oral bacterial samples were collected in the radiotherapy group and the negative control group. On the 3 rd, 5 th, 7 th, and 9 th days post-radiotherapy, the tongue tissues were obtained from another batch of mice in the negative control and radiotherapy groups. Inflammatory factors were detected with PCR and HE staining was performed. Results:The oral bacterial diversity of patients after radiotherapy significantly differed from that of patients before radiotherapy and their accompanying family members before and after radiotherapy in Observed species, Chao1, Simpson index (all P<0.05). There was a significant difference in Shannon index between the severe and mild ROM patients ( P=0.036). LEfSe analysis showed that patients with severe ROM had higher levels of g_ Streptococcus and f_ Streptococcus, and lower levels of f_ Familyxl, g_ Gemini and o_ Bacillus. The Simpson index and PCoA results in the oral bacterial samples significantly differed between the negative control and radiotherapy groups (all P<0.05). Conclusions:Radiotherapy can disrupt the balance of bacterial flora. The dysregulated oral bacterial flora is closely associated with the aggravation of ROM.

Analysis in saliva microbiome composition in patients with NAFLD and normal subjects / 实用医学杂志

Objective To analyze the diversity of salivary bacteria in patients with nonalcoholic fatty liv-er disease(NAFLD group)and healthy control group(HC group). Methods Saliva samples were collected from 24 patients with nonalcoholic fatty liver disease and 22 healthy control.Genomic DNA of the samples was extracted and extended to 16S rRNA V4-V5 hypervariable region after PCR with Illumina high-throughput sequencing tech-nology.All the data,including operational taxonomic units,diversity indexes and species annotation,etc.was ana-lyzed. Results 39118 optimized sequences in the saliva of each group were obtained,including nonalcoholic fatty liver group clustering OTUs about 308 ± 48 and healthy control group clustering OTUs about 305 ± 53.The diversi-ty analysis of NAFLD group and HC group showed that there was little difference in diversity of the whole salivary bacteria.The data of the species analysis of the saliva bacteria in two group indicate that the composition was simi-lar and the relative abundance was different in phylum and genus.In NAFLD group,the ratio of the abundance of firmicutes(20.42%)increased and the proportion of bacteroides(36.75%)decreased in phylum. Genus of the NAFLD group,the ratio of fusobacterium,porphyromonas and veillonella increased significantly,and the ratio of prevotella and[Prevotella]decreased.Conclusion In the NAFLD group,the abundance of firmicutes increased, and the abundance of the bacteria decreased.It was speculated that the imbalance of the salivary bacteria is associ-ated with nonalcoholic fatty liver disease.

Genome Analysis Of Streptococcus Gordonii SK12

The gram-positive, mesophilic and non-motile coccus Streptococcus gordonii is an important causativeagent of infective endocarditis (IE). This pioneer species of dental plaque also causes bacteraemiain immune-supressed patients. In this study, we analysed the genome of a representative strain,Streptococcus gordonii SK12 that was originally isolated from the oral cavity. To gain a better understandingof the biology, virulence and phylogeny, of this potentially pathogenic organism, high-throughput IlluminaHiSeq technology and different bioinformatics approaches were performed. Genome assembly of SK12was performed using CLC Genomic Workbench 5.1.5 while RAST annotation revealed the key genomicfeatures. The assembled draft genome of Streptococcus gordonii SK12 consists of 27 contigs, with agenome size of 2,145,851 bp and a G+C content of 40.63%. Phylogenetic inferences have confirmedthat SK12 is closely related to the widely studied strain Streptococcus gordonii Challis. Interestingly, wepredicted 118 potential virulence genes in SK12 genome which may contribute to bacterial pathogenicityin infective endocarditis. We also discovered an intact prophage which might be recently integratedinto the SK12 genome. Examination of genes present in genomic islands revealed that this oral strainmight has potential to acquire new phenotypes/traits including strong defence system, bacitracinresistance and collateral detergent sensitivity. This detailed analysis of S. gordonii SK12 further improvesour understanding of the genetic make-up of S. gordonii as a whole and may help to elucidate howthis species is able to transition between living as an oral commensal and potentially causing the lifethreateningcondition infective endocarditis.

The effect of ceramometal bridge on the local oral flora / 实用口腔医学杂志

Objective:To investigate the effect of the ceramometal b ridge on the local gingival groove flora.Methods: Classi cal bacterial incubation and identification were used to study the changes of th e local gingival groove flora in 6 patients wearing ceramometal bridge for 1 wee k to 3 months. Results: 3 months after the prosthetic procedure the CFU o f P.melaninogenica, Gram-positive bacilli cmainly Actinomyces and the t otal bacteria were significantly increased (P