胃源性柠檬双面神菌的耐药和毒力全基因组分析
Whole Genome Sequencing of Janibacter melonis from the Stomach and Virulence and Antibiotic-Resistant Gene Analysis

【目的】从基因组水平上探讨胃源性柠檬双面神菌PA32株的耐药性和致病机制。【方法】采用耐酸实验测定PA32菌株的耐酸能力，采用纸片扩散法测定PA32菌株对4种抗菌药物的敏感性，利用三代测序平台对其进行全基因组测序和组装，利用glimmer进行基因预测，利用VFDB数据库、CARD数据库进行毒力和耐药基因功能注释。【结果】耐酸实验表明，PA32菌株能够耐受pH 2的酸性环境。药敏实验表明，PA32菌株对甲硝唑耐药，对克拉霉素、四环素、左氧氟沙星均敏感。该菌株的基因组包括一条完整的环状染色体序列，染色体长度为3,459,946 bp，鸟嘌呤–胞嘧啶(GC)含量为73.1%，编码3296个基因。PA32菌株含有黏附和(或)侵袭、分泌系统和无氧呼吸相关毒力基因，以及对氟喹诺酮类、氨基糖苷类、四环素类、大环内酯类、β-内酰胺类等多种抗生素的耐药基因。【结论】胃源性柠檬双面神菌耐酸能力强，从基因组学水平分析具备致病潜力，这与其携带的多种毒力基因和耐药基因相关。
[Objective] To investigate the drug resistance and pathogenic mechanism of a Janibacter melonis strain PA32 at the genome-wide level. [Method] The acid resistance capacity of strain PA32 was de-termined by acid resistance assay. The susceptibility of PA32 strain to 4 antimicrobial agents was determined by disk diffusion method. Whole genome sequencing and assembly of PA32 were con-ducted by the three-generation sequencing platform, and gene prediction was conducted using glimmer, and functional annotation of virulence and drug resistance genes was conducted using VFDB database and CARD database. [Result] The PA32 strain could withstand the acidic environ-ment at pH 2. The PA32 strain was resistant to metronidazole, and susceptible to clarithromycin, tetracycline and levofloxacin. The complete genome sequence of PA32 comprises a 3,459,946 bp circular chromosome containing 3296 genes with the guanine-cytosine (GC) content of 73.1%. PA32 strain contained virulence genes related to adhesion, secretion system and anaerobic respiration, as well as drug resistance genes to fluoroquinolones, aminoglycosides, tetracycline, macrolides, β-lactam and other antibiotics. [Conclusion] Isolated from the stomach, J. melonis displays a strong ability of acid resistance. Comparative genomics indicate that J. melonis has pathogenic potential, which is associated with its multidrug resistance genes and virulence genes.