Analysis of a phage with unique phenotypic characteristics of plague isolated from Gengma County,Yunnan
Objective To analyze the characteristics of the temperature-dependent Yersinia pestis bacteriophage(GMS190),to provide further evidence for exploring the microecology of the plague in its endemic areas.Methods Using the plague vaccine strain EV76 as the host bacterium,plague bacteriophages were isolated and purified from mouse cecum samples.Their morphology under electron microscopy was observed,and their biological characteristics such as plaque formation efficiency,adsorption rate,host range at different temperatures,as well as genomic features were analyzed.Results The bacteriophage belongs to the Myoviridae family.GMS190 optimally lysed Yersinia pestis strain EV76 at 28 ℃,but could not lyse EV76 at 37 ℃.Adsorption experiments and ECOI experiments showed that phage adsorption was not inhibited at 37 ℃,nor did abortive infection occur.The host range determination revealed that GMS190 could lyse some Shigella species.When infecting a strain of Escherichia coli(E-e),its temperature-dependent characteristics were opposite to those when infecting Yersinia pestis EV76,it could not lyse at 21 ℃ but could lyse at 37 ℃.Whole-genome comparison analysis showed that GMS190 had a high similarity to the Yersinia pestis bacte-riophage HQ103(coverage rate was 87％,similarity rate was 97.95％),yet their temperature-dependent lysis characteristics were opposite.Conclusion This study elucidates the biological and genomic characteristics of the newly isolated temperature-dependent lysing bacteriophage of plague,and preliminarily discusses its biological significance.
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