一株宋内志贺菌的分离鉴定及基因组分析

Isolation, identification and genome analysis of Shigella sonnei

目的通过对口岸腹泻样本中分离到的志贺菌鉴定及全基因组的测序和分型研究,对志贺菌从致病性、抗药性及分子分型进行全面分析,建立入境腹泻病原体风险分析流程。方法对细菌的选择性培养基进行初筛后,分离菌株通过全自动微生物鉴定仪及实时荧光PCR的方法进行鉴定。对分离菌株进行全基因组测序、组装、注释、进化分析,通过多位点序列分型(MLST)方法进行分型。结果本次从口岸腹泻样本中成功分离到的志贺菌鉴定为宋内志贺菌,得到全长基因组4 817 693 bp,GC含量51.0%,注释了4 811个编码基因。对基因组分析发现了4种耐药基因及多种志贺毒素基因,进化研究表明该菌株与宋内志贺菌Ss046同源性最高,通过MLST方法分型为ST152克隆群。结论通过对志贺菌分离菌株鉴定及基因组学分析及分型,建立入境志贺菌分型溯源及风险分析流程,为口岸传染病疫情监控提供技术支撑。

Objective Through the identification of Shigella isolated from the diarrhea samples at the port and the sequencing and typing of whole genome,the comprehensive analysis of Shigella from pathogenicity,drug resistance and molecular typing was carried out and also a risk analysis process for entry diarrhea pathogens was established.Methods After initial screening by the selective medium of bacteria,the isolated strain was identified by a fully automated microbial identification instrument and Real-time fluorescent PCR.Whole-genome sequencing,assembly,annotation,and evolution analysis of the isolated strains were performed by the multi-site sequence typing(MLST)method.Results The Shigella strain successfully isolated from the port diarrhea samples was identified as Shigella sonnei,and the full-length genome was 4 817 693 bp,the GC content was51.0%,and 4 811 coding genes were annotated.Four drug resistance genes and various Shiga toxin genes were found in genomic analysis.The evolutionary studies showed that the strain had the highest homology with Shigella sonnei Ss046 and was classified into ST152 clonal group by MLST method.Conclusion Through the identification and genomics analysis and classification of Shigella isolates,the process of typing traceability and risk analysis was established for the in ported Shigella,providing technical support for the surveillance of infectious diseases at the port.