Objective To analyze the biological characteristics of Yersinia pestis strains in Haixi Prefecture,Qinghai Province,in order to provide a scientific basis for plague prevention and control in future.Methods Totally 18...Objective To analyze the biological characteristics of Yersinia pestis strains in Haixi Prefecture,Qinghai Province,in order to provide a scientific basis for plague prevention and control in future.Methods Totally 181 strains were separated from variety kinds of host in Haixi Prefecture,Qinghai Province from 1957 to 2011,and these strains were conducted biochemical test,virulence factor evaluation,plasmid analysis,different region(DFR)genotyping,drug and disinfectant resistant genes detection;79 of the 181 strains were examined by toxicity test and classified according to the criteria(minimum lethal dose:MLD≤10000 was velogenic strain,10000<MLD<100000 was moderate virulence strain,MLD≥100000 was hypovirulent strain).Results According to six biochemical typing about gelatin candy,rhamnose,maltose,melibiose,glycerin and denitrification,the 181 strains of Yersinia pestis were antique biovar and Qing-Tibet Plateau ecotype.A proportion of 81.22%(147/181)of Yersinia pestis strains contained all the four virulence factors(F1,PstⅠ,VW,Pgm).Totally 63.54%(115/181)of the strains contained 3 kinds of plasmid-6×106,45×106,and 52×106;31.49%(57/181)of the strains contained 3 kinds of plasmid-6×106,45×106,and 65×106.The strains had 8 genomovars,and were given priority to genomovar 8(109 strains),secondly,genomovar 32(33 strains),genomovar 5(20 strains),genomovar 1b(14 strains),genomovar 44(2 strains),genomovar 7(1 strain),genomovar 37(1 strain),and genomovar 49(1 strain).Among the 181 Yersinia pestis strains,strains with genes related to streptomycin resistance,sulfanilamide resistance,beta lactam resistance and disinfectant resistance were not found;and 75 of 79 strains were velogenic strains by toxicity test(MLD≤10000),accounting for 94.94%(75/79).Conclusion The strains separated in Haixi Prefecture,Qinghai Province have the characteristics of Qinghai-Tibet Plateau plague's pathogen and have strong toxicity;all strains are not drug-and disinfectant-resistance genes.展开更多
文摘Objective To analyze the biological characteristics of Yersinia pestis strains in Haixi Prefecture,Qinghai Province,in order to provide a scientific basis for plague prevention and control in future.Methods Totally 181 strains were separated from variety kinds of host in Haixi Prefecture,Qinghai Province from 1957 to 2011,and these strains were conducted biochemical test,virulence factor evaluation,plasmid analysis,different region(DFR)genotyping,drug and disinfectant resistant genes detection;79 of the 181 strains were examined by toxicity test and classified according to the criteria(minimum lethal dose:MLD≤10000 was velogenic strain,10000<MLD<100000 was moderate virulence strain,MLD≥100000 was hypovirulent strain).Results According to six biochemical typing about gelatin candy,rhamnose,maltose,melibiose,glycerin and denitrification,the 181 strains of Yersinia pestis were antique biovar and Qing-Tibet Plateau ecotype.A proportion of 81.22%(147/181)of Yersinia pestis strains contained all the four virulence factors(F1,PstⅠ,VW,Pgm).Totally 63.54%(115/181)of the strains contained 3 kinds of plasmid-6×106,45×106,and 52×106;31.49%(57/181)of the strains contained 3 kinds of plasmid-6×106,45×106,and 65×106.The strains had 8 genomovars,and were given priority to genomovar 8(109 strains),secondly,genomovar 32(33 strains),genomovar 5(20 strains),genomovar 1b(14 strains),genomovar 44(2 strains),genomovar 7(1 strain),genomovar 37(1 strain),and genomovar 49(1 strain).Among the 181 Yersinia pestis strains,strains with genes related to streptomycin resistance,sulfanilamide resistance,beta lactam resistance and disinfectant resistance were not found;and 75 of 79 strains were velogenic strains by toxicity test(MLD≤10000),accounting for 94.94%(75/79).Conclusion The strains separated in Haixi Prefecture,Qinghai Province have the characteristics of Qinghai-Tibet Plateau plague's pathogen and have strong toxicity;all strains are not drug-and disinfectant-resistance genes.