Page 23 - 南京医科大学学报自然科学版

第42卷第8期 南京医科大学学报（自然科学版）
2022年8月 Journal of Nanjing Medical University（Natural Sciences） ·1065 ·

·基础研究·

大肠杆菌J2_5的全基因组测序及比较基因组分析

支娅茹，张 莹，于鑫焱 ，刘晓秋 *
*
南京医科大学病原生物学系，江苏省现代病原生物学重点实验室，江苏 南京 211166

［摘 要］ 目的：分析多耐药大肠杆菌J2_5的进化分群、耐药基因及毒力基因，为临床诊断及用药提供理论依据。方法：采用
高通量测序法对J2_5进行全基因组测序，并使用多种生物信息学工具和数据库进行数据比对分析。结果：该菌的全基因组总
长度为4.7 Mb，GC含量为50.78%。多位点序列分型（MLST）分析发现其ST型为ST2491，和大肠杆菌野生株 MG1655分型ST10
不同。系统发育树进一步分析表明J2_5与MG1655的亲缘关系较近。抗生素耐药性综合数据库（CARD）分析发现该菌有65
个耐药基因，主要通过4类耐药机制（抗生素外排泵、抗生素失活、抗生素靶点改变、降低对抗生素的渗透性）产生耐药性。毒
力因子数据库（VFDB）分析发现该菌有7类40个毒力基因，编码黏附素、侵袭、自主转运蛋白等毒素蛋白。使用Prophage Hunt⁃
er网上工具发现J2_5基因组存在3个前噬菌体，并且前噬菌体上带有1个毒力基因。结论：全基因组测序结果表明J2_5携带
更多的毒力基因及耐药基因，是其致病性强和具有多种抗生素耐药性的原因。
［关键词］ 大肠杆菌；全基因组；MLST；系统发育；耐药基因；毒力基因；原噬菌体
［中图分类号］ R378.21 ［文献标志码］ A ［文章编号］ 1007⁃4368（2022）08⁃1065⁃09
doi：10.7655/NYDXBNS20220803

Whole genome sequencing and comparative genomics analysis of Escherichia coli J2_5
*
ZHI Yaru，ZHANG Ying，YU xinyan ，LIU Xiaoqiu *
Jiangsu Key Laboratory of Pathogenic Biology，Nanjing Medical University，Nanjing 211166，China

［Abstract］ Objective：A novel multidrug resistant（MDR）Escherichia coli（E.coli）strain J2_5 was isolated from a patient’s mid⁃
stream urine sample. According to the genome sequence of J2_5，we analyzed its evolutionary classification，drug resistance genes and
virulence genes，providing theoretical basis for clinical diagnosis and drug selection for drug resistant bacterial infection. Methods：
Genome DNA of J2_5 was isolated and sequenced by high ⁃ throughput sequencing technology，after analyzed the high ⁃ throughput
sequencing data and compared it with known databases by a variety of bioinformatics tools，a high integrity genome of J2_5 was obtained.
Results：The total length of the whole genome of J2_5 was 4.7Mb and GC content was 50.78%. Phylogenetic tree analysis showed that J2_
5’genome was closely related to that of wild type E. coli strain MG1655. But Multilocus sequence typing（MLST）analysis revealed ST
type of J2_5 was ST2491，which was different from that of MG1655（ST10）. Furthermore，CARD database analysis showed that the
genome of J2_5 encodes 65 drug resistance genes，which make the strain obtain drug⁃resistant ability through four different mechanisms
（antibiotic efflux pump，antibiotic inactivation，antibiotic target change，reduced permeability to antibiotics）. VFDB database analysis
showed that there were 40 virulence genes in 7 categories，encoding adhesive proteins，invasion proteins，autonomic transporters and other
toxin proteins. After analyzing the whole genome of J2_5 through the Prophage Hunter online tool，we found that there were three
prophages in the genome of J2_5，and a virulence gene was carried by one of the prophages. Conclusion：The whole genome sequencing
results showed that J2_5 carries some virulence genes and drug resistance genes，which makes the strain obtain strong pathogenicity and
resistance ability to a variety of antibiotics.
［Key words］ Escherichia coli；whole genome；MLST；phylogeny；drug resistance gene；virulence gene；prophage
［J Nanjing Med Univ，2022，42（08）：1065⁃1072，1079］

［基金项目］ 国家自然科学基金（81501797，31800156）
∗
通信作者（Corresponding author），E⁃mail：xiaoqiulliu@njmu.edu.cn；xyyu@njmu.edu.cn