Study On The Phenotype And Genotype Of Newly Isolated Yersinia Pestis In Yunnan Province In 2017

[Objective]To understand the phenotype and genotypic characteristics of the newly isolated Yersinia pestis in Heqing County,the source of the new plague foci in Yunnan Province,and to trace the source to analyze the nature and source of the plague bacteria of Heqing,in order to develop the source of the disease.The scientific and scientific prevention and control strategy provides a scientific basis.[Methods]1.Phenotypic determination: fermentation experiments of arabinose,sucrose,rhamnose,maltose and glycerol,denitrification test,VW virulence factor test,pigmentation factor detection and nutritional requirements to determine the table of Yersinia pestis type feature.2.Using the methods of DFR、CRISPR and MLVA(12+14 strategy)to determine the Genotypes of Yersinia pestis in Heqing County,and to use the BN6.6 software for traceability analysis.[Results]1.Both Lijiang County strains,Jianchuan strains,and Heqing strains ferment arabinose,maltose,glycerol and the nitrogen-positive,biotype belongs to the classical variant of Yersinia pestis;All the strains are VW+ strains,the plague pigmentation factor are positive,the nutrient requirement type is phenylalanine-dependent and glutamate-independent.2.All the 10 strains of Yersinia pestis strains in Heqing had the same DFR type of Genomovar 05(deficient in DFR 01,02,13,and 23,and the remaining sites were not deleted),which was the same as that of Lijiang strain.3.In the CRISPR classification of all strains in Heqing,YPa is sorted as“a1-a2-a3-a4-a5-a6-a7”,YPb is “b1-b2-b3-b4”,and YPc is “c1-c2-c3”.The same type as the Lijiang strain S is the gene cluster Ca7.4.The strains of Yersinia pestis in Heqing were located in the plague cluster of Lijiang wild rat,and there is only one difference between HQ1 in site M22.and homologous with Lijiang strain 2006-7 which located at the core of the entire Lijiang wild rat plague cluster.[Conclusions]1.The strains of Yersinia pestis in Heqing,Yulong and Jianchuan belong to the same biological type,all of which are classical variants of Yersinia pestis,and the virulence factors and nutritional requirements are consistent.The strains of Yersinia pestis isolated from Heqing,Yunnanin province was consistent with the same strain of Lijiang wild mice plague in the classification of CRISPRs,MLVA(14+12)and DFR classification.Indicating that this occurred in Heqing,Yulong and Jianchuan County,Yunnan Province,belonged to the same epidemic.As a result of the further spread of the source to the south,in view of the high pathogenicity of this type of plague,the continuous monitoring of the source should be strengthened,and the epidemic situation should be handled to reduce the risk of transmission to humans.