Isolation and determination of lysate spectrum of plague bacteriophages in new rodent plague foci Heqing,China
WANG Bo1,2, ZHONG You-Hong2, DING Yi-Bo2, GUO Ying2, DUAN Cun-Juan2, ZHANG Hai-peng2, ZHAO Dan-ni2, TAN Hong-Li2, LI Wei3, WANG Peng2
1. Kunming Medical University, Kunming, Yunnan, 650106; 2. Yunnan provincial Key Laboratory for zoonosis control and prevention, Yunnan Institute for Endemic Disease Control and Prevention, Dali, Yunnan 671000; 3. National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Abstract:To make clear whether there are Yersinia pestis phages in the new plague focus of Heqing County, and to perform morphological identification and lysate spectrum. When natural villages within 5 km were determined as sampling points, rats were caught by rattan method. The small intestine of mice was taken from the laboratory and put in the modified PBS. The samples were screened and purified by the double-layer plate method. Phage plaques were observed with naked eyes, and the morphology of bacteriophage was examined by electronic microscopy. Pyrolysis characteristics of 21 strains of Yersinia pestis and 115 strains of non-Yersinia pestis at four temperatures of 22 ℃, 24 ℃, 28 ℃ and 37 ℃ respectively. 1. A total of 354 specimens were collected and two strains of plague phages were isolated. 2. 2 strains of bacteriophages could lyse Yersinia pestis at temperatures higher than 24℃, but could not lyse Yersinia pestis at temperatures lower than 24℃, while all of non-Yersinia pestis did not lyse at four temperatures. 3. Electron microscopic examination showed that two phage strains belonged to the family of Myoviridae. There are plague bacteriophages in the new plague focus of Heqing, and the plague bacteriophages can lyse the Yersinia pestis only above 24℃, which is related to their long-term existence in Heqing County. At the same time, the two bacteriophages are of narrow lysis spectrum and well specificity, which can be used for the screening of alternative diagnostic bacteriophages.