ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2015, Vol. 46 ›› Issue (9): 1593-1599.doi: 10.11843/j.issn.0366-6964.2015.09.014

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Isolation and Identification of Citrobacter freundii from the Diseased Small Tail Han Sheep

LIU Hui-sheng1,ZHAO Zhan-qin1* ,XUE Yun2,XUE Qiao1,WANG Yang1,CHANG Shi-kai1,LIU Yuan1   

  1. (1.Lab of Veterinary Microbiology,College of Animal Science and Technology,Henan University of Science and Technology,Luoyang 471003,China;2.Lab of Medical Engineering,College of Medical Technology and Engineering,Henan University of Science and Technology,Luoyang 471003,China)
  • Received:2015-01-09 Online:2015-09-23 Published:2015-09-23

Abstract:

To determine the pathogenic bacterium infecting the small tail Han Sheep,three strains,named LK-1,LK-2 and LK-3,were isolated from the heart,liver,spleen,lungs,kidney and intestines of three dead cases on a sheep farm in Henan province.Identification by the Biolog Microbial Identification System,and further 16S rRNA sequence and phylogenetic analysis demonstrated that the three isolates were Citrobacter freundii.Infection with the bacterial suspension to the healthy small tail Han Sheep could reproduce the diseased symptoms as occurred naturally and the same bacterium could be recovered from these infected sheep.Three isolates also have certain pathogenicity to the BALB/c mice,with the lethal doses of 5.0×107,6.0×107,5.8×107 CFU,respectively.The susceptibility test to antibiotics demonstrated that three isolates LK-1,LK-2 and LK-3 were susceptible to 14 drugs,including cefotaxime,gentamicin,tetracycline,chloramphenicol,enrofloxacin,etc.Three isolates have similar antimicrobial resistance profiles to 17 of 21 drugs in this study.But they have different profiles to 4 drugs,including amoxicillin,cefaclor,streptomycin and azithromycin.In this study,we reported the pathogenicity on Small Tail Han sheep of Citrobacter freundii at home and abroadfor the first time.Citrobacter freundii is the pathogen of the dead small tail Han Sheep cases.

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