›› 2019, Vol. 46 ›› Issue (2): 548-556.doi: 10.16431/j.cnki.1671-7236.2019.02.026

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Isolation,Identification and Partial Biological Characteristics of Mannheimia haemolytica in Shipping Fever of Beef Cattle

HAN Xiaoli, REN Jingjing, YANG Mingwei, ZHU Ling, ZHANG Rui, YAN Genqiang   

  1. College of Animal Science and Technology, Shihizi University, Shihezi 832000, China
  • Received:2018-06-12 Online:2019-02-20 Published:2019-02-20

Abstract:

In order to identify the pathogens and biological characteristics of shipping fever of beef cattle.The bacteria of blood (heart),lung,liver and spleen were collected and isolated,biochemical tested,and PCR identified,the virulence gene detection and pathogenicity of the isolates were studied.The results showed that 7 isolates were Gram-negative brevibacterium with weak β-hemolysis,Wright's staining result showed that there was two-pole dense staining and obvious capsule.The biochemical test results showed that the isolated bacteria could ferment carbohydrates such as glucose,maltose,arabinose,mannitol,mannose,xylose etc.and do not ferment urease, MR-VP and indole.It could utilize carbohydrates such as glucose to produce a small amount of acid without gas production,and the results were consistent with the biochemical characteristics of Mannheimia haemolytica.The isolates were capsular serum A2 type by PCR,which contained three virulence genes of the type Ⅳ fimbriae-related gene ptfA,the copy-related gene dnaN,and the interleukin related gene LktC.The LD50 values of the bacteria in mice ranged from 107.83 to 108.50CFU/mL,there were some difference of LD50 values in different strains.The results showed that the pathogen which caused the shipping fever in the batch of beef cattle was Mannheimia haemolytica with capsular serum A2 type,which provided a reference for further study of the pathogenic mechanism of Mannheimia haemolytica.

Key words: beef; Mannheimia haemolytica; identification; biological characteristics

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