[Isolation and biological characteristics on Yersinia pestis phage YP060].

OBJECTIVE

To isolate and identify the characteristics of Yersinia pestis phage YP060 from mice nests in Yunnan plague focus.

METHODS

Phage YP060 was isolated from Yunnan plague focus by double-layer agar plate method with attenuated vaccine Yersinia pestis strain EV76 as the host bacterium. Phage particle was observed under the electron microscope while biological properties of phage YP060 including lytic capacity, host spectrum, optimal multiplicity of infection (MOI), one-step growth curve, sensitivity to temperature, pH, ultraviolet ray and chloroform etc. were identified.

RESULTS

The particles of phage YP060 presented tadpoles-like features, with optimal multiplicity of infection as 0.1. Latent period and burst period appeared as 50 min and 80 min, respectively. The phage endured the temperature between 30-50 ℃, and it contained a stronger lysis activities in a range of pH 5 to 10. Phage YP060 was sensitive to ultraviolet rays but insensitive to chloroform while presented special lysic ability to Yersinia pestis.

CONCLUSION

Yersinia pestis phage YP060 was isolated for the first time from mice nests in plague natural focus in China. Our findings related to narrow host spectrum and stronger lysis activities.