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目的对1株可疑菌株进行系列验证实验,以确定其是否为鼠疫耶尔森氏菌(以下简称鼠疫菌)。方法用鼠疫细菌学常规方法和分子生物学手段确定其生物学表型特征、特异性基因及基因组特征。结果该菌株具备鼠疫菌的典型形态特征;能被鼠疫噬菌体完全裂解;主要生化特性为阿胶糖(+)、鼠李糖(-)、麦芽糖(+)、蜜二糖(-)、甘油(+)、脱氮(+),与典型鼠疫菌一致。毒力因子检查结果为均为阴性;对实验动物小白鼠完全无致死能力。全基因组芯片杂交实验和PCR扩增表明55023菌株没有鼠疫菌的三个质粒;也不具鼠疫标识基因;pgm位点代表性基因YPO1954扩增阳性,YPO1908扩增阴性,表明其pgm位点不完整;差异片段(DFR)分型结果表明该菌株缺失了14个DFR,不符合鼠疫菌的特征;多位点序列分型(MLST)分析结果表明该菌株与鼠疫存在16个碱基的差异,而与血清Ⅲ型假结核耶尔森氏菌仅相差两个碱基。结论尽管55023菌株具备鼠疫菌的一些表型特征,但基因组特征表明其不是鼠疫菌,而可能是血清III型的假结核耶尔森氏菌;噬菌体裂解结果等表型不能作为鼠疫菌鉴定的最终标准。
Objective To carry out a series of validation experiments on one suspicious strain to determine if it is Yersinia pestis (hereinafter referred to as Yersinia pestis). Methods The biological phenotypic characteristics, specific genes and genomic characteristics were determined by plague bacteriology and molecular biology methods. Results The strain had the typical morphological characteristics of Y. pestis and was completely lysed by phage plague. The main biochemical characteristics of the strain were as follows: gelatin (+), rhamnose (+), maltose (+), melibiose (-), glycerol ), Denitrification (+), consistent with the typical Yersinia pestis. Virulence factor test results were negative; experimental animals without lethal ability of mice. Whole genome chip hybridization experiments and PCR amplification showed that the 55023 strain did not have three plague bacterium plasmids nor the plague marker gene; the pgm locus representative gene YPO1954 amplified positive, YPO1908 negative, indicating that the pgm site is incomplete; The results of DFR typing showed that the strain lacked 14 DFRs and was not consistent with the characteristics of Y. pestis. MLST analysis showed that there was a 16-base difference between this strain and the plague, Yersinia pseudotuberculosis serotype III differs only by two bases. CONCLUSION Although the 55023 strain possesses some phenotypic characteristics of Y. pestis, the genomic characteristics indicate that it is not Yersinia pestis and may be serotype III Yersinia pseudotuberculosis; the phenotype such as the result of phage lysis can not ultimately be identified as Yersinia pestis standard.