Analysis Of Conjunctival Sac And Lacrimal Sac Microbiota In Patients With Chronic Dacryocystitis Based On 16SrRNA Sequencing Technology

Objective: By using 16 SrRNA sequencing technology,the microbial status in the conjunctival sac and lacrimal sac of patients with chronic dacryocystitis was investigated and analyzed,and the relationship and microbial community characteristics between the two were compared,providing a reference direction for the study of chronic dacryocystitis microorganisms.Methods: Twenty patients with chronic dacryocystitis who visited our hospital from August 2020 to October 2021 were selected for the study.The conjunctival sac was first rinsed with physiological saline,and then disinfected with iodophor around the collection area.Then,sterile physiological cotton swabs were taken from the conjunctival sac of the patient’s eyes,and secretions in the lacrimal sac were collected using a sterile irrigator and applied to sterile physiological cotton swabs.All swabs were collected and stored in a-80 degree refrigerator,Within one week,it will be stored in dry ice and transported to Nanjing Parsenor Biological Co.,Ltd.for analysis within 8hours.Subsequently,the database will be built using the software Tru Seq Nano DNA LT Library Prep Kit provided by Illumina.For libraries that meet the requirements,the Nova Seq 6000 SP Reagent Kit(500cycles)will be used based on the Illumina Nova Seq device × Perform V3-V4 high variability dual end sequencing on all bacteria in the sample at 250 bp,analyze the diversity of bacterial communities in the secretion swab and conjunctival sac swab of the lacrimal sac,and analyze their microbial diversity.Results: 1.The sequencing results indicate that there is a diverse bacterial community in the secretion of the lacrimal sac and conjunctival sac of patients with dacryocystitis.The analysis of the two groups at the phylum level shows that the top 10 phyla in the lacrimal sac group are: Proteobacteria,Firmicutes,Fusobacteria,Tenericutes,Actinobacteria,Bacteroidetes,Cyanobacteria,TM7,Spirochetes,Thermobacteria.The top 10 phyla in the conjunctival sac group are in order: Proteobacteria,Firmicutes,Fusobacteria,Cyanobacteria,Actinobacteria,Tenericutes,Bacteroidetes,TM7,Thermobacteria and Spirochaetes.Analysis of the microbial abundance composition of each sample at the genus level showed that the bacterial flora of lacrimal sac inflammation group(LN)was more than that of conjunctival sac group(JML),which was mainly divided into: Streptococcus,Haemophilus,Mycoplasma,Fusobacterium,Corynebacterium.The flora composition of dacryocystitis group less than conjunctival sac group was mainly divided into: Pseudomonas,Cupriafidus,Weissella,Corynebacterium,Chelatococcus.2.Alpha diversity analysis showed that the Chao1 index,Shannon,and Simpson index of the conjunctival sac group were relatively higher than those of the lacrimal sac group,indicating that their bacterial richness and diversity were higher than those of the lacrimal sac group.However,the difference between the conjunctival sac group and the lacrimal sac group was not statistically significant(P>0.05).3.Based on 97% similarity analysis of 34 samples,there were 2517 ASV/OUT in the conjunctival sac group,2255 ASV/OUT in the lacrimal sac group,and a total of 1145ASV/OUT.This indicates that there are more species in the conjunctival sac group than in the lacrimal sac group,but similar species also exist.4.There was no significant difference in the bacterial flora between the two groups.Conclusion: 16 srRNA sequencing technology is an efficient,accurate,and fast technique for studying microorganisms.This study analyzed the lacrimal sac secretion and conjunctival sac flora of patients with chronic dacryocystitis through high-throughput sequencing technology,basically achieved the expected experimental goal,preliminarily understood the flora types,analyzed that there was no significant difference in the microbial community between the two,and preliminarily explored the difference between the conjunctival sac flora of patients with chronic dacryocystitis and healthy adults.Due to the small sample size and the presence of certain contamination during sample size collection,which has caused certain errors in the experimental results,it is necessary to expand the sample size and improve the relevant design in order to improve the research.