Abstract: Objective　To investigate the bacterial community diversity in human Demodex mites, so as to provide insights into unraveling the role of human Demodex mites in them caused infectious diseases. Methods　From June to July 2023, Demodex mites were collected from the faces of college students in a university in Wuhu City using the adhesive tape method, and the V4 region of 16S ribosomal RNA (16S rRNA) gene and the internal transcribed spacer (ITS) gene of nuclear ribosomal DNA were amplified on an Illumina PE250 high⁃throughput sequencing platform. Sequencing data were spliced according to the overlapping relations and filtered to yield effective sequences, and operational taxonomic units (OTUs) clustering was. The diversity index of obtained OUTs was analyzed, and the structure of the bacterial community was analyzed at various taxonomic levels. Results　A total of 57 483 valid sequences were obtained using 16S rRNA gene sequencing, and 159 OUTs were classified according to similarity. Then, OUTs at a 97% similarity were included for taxonomic analyses, and the bacteria in Demodex mites belonged to 14 phyla, 20 classes, 51 orders, 72 families, and 94 genera. Proteobacteria was the dominant phylum, and Vibrio, Bradyrhizobium and Variovorax were dominant genera. A total of 56 362 valid sequences were obtained using ITS gene sequencing, and 147 OTUs were obtained, which belonged to 5 phyla, 17 classes, 34 orders, 68 families, and 93 genera and were annotated to Ascomycota, Basidiomycota and Chytridiomycota, with Ascomycota as the dominant phylum, and Alternaria alternata, Epicoccum, Penicillium, and Sarocladium as dominant genera. Conclusions　There is a high diversity in the composition of bacterial communities in human Demodex mites, with multiple types of microorganisms and high species abundance.

Key words: Human Demodex mite, Bacterial community, Community diversity, 16S ribosomal RNA, Internal transcribed spacer

摘要： 目的　分析人体蠕形螨体内细菌群落多样性，为探究蠕形螨在其所致传染病中的作用提供参考依据。方法 　 2023年6—7月通过透明胶纸法采集芜湖市某高校大学生面部蠕形螨，通过Illumina PE250高通量测序平台扩增16S核糖体RNA（16S ribosomal RNA，16S rRNA）基因V4区以及核糖体DNA内转录间隔区（internal transcribed spacer，ITS）基因，将测序结果根据重叠关系进行拼接、过滤得到有效序列，再进行操作分离单元（operational taxonomic units，OTU）聚类。对得到的OTU进行多样性指数分析，并在不同分类水平对细菌菌落结构进行统计分析。结果　16S rRNA测序获得57 483条有效序列，根据不同相似度水平对其进行OTU分类，得到159个OTUs；对其中97%相似水平的OTU进行分类学水平分析，发现人体蠕形螨体内细菌分属于14个门、20个纲、51个目、72个科、94个属。在门分类水平，变形菌门为优势菌门；在属分类水平上，弧菌属、慢生根瘤菌和贪噬菌属为优势菌属。ITS测序共获得56 362条有效序列及147个OTUs，分属于5个门、17个纲、34个目、68个科、93个属；注释到子囊菌门、担子菌门、壶菌属门和毛囊菌门等，子囊菌门为优势菌门，链格孢菌属、附球菌属、青霉菌属和帚枝霉属为优势菌属。结论　蠕形螨体内细菌群落组成具有较高多样性，同时微生物种类较多、物种丰度较高。

关键词: 人体蠕形螨, 细菌群落, 群落多样性, 16S核糖体RNA, 内转录间隔区