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Home » Archive » 2013

TDK conference 2013

Serotypes of Mannheimia haemolytica and Bibersteinia trehalosi strains isolated from ruminants
Szalay Dóra - year 5
SzIU, Faculty of Veterinary Science, Department of Microbiology and Infectious Diseases
Supervisor: Fodor László DVM

Abstract:

Background:

Bacterial infection from the Mannheimia haemolytica (M. haemolytica) and Bibersteinia trehalosi (B. trehalosi) strains lead to severe clinical outcome in rudiments. M. haemolytica infection happens in young calves specifically after various viral, or Mycoplasma infection, and often manifests as pneumonia. M. haemolytica pneumonia in cattle is an important part of bovine respiratory disease complex (BRDC). M. haemolytica infection manifests as pneumonia in sheep and in goats, but causes bacteremia and sepsis in lambs and yeanlings. On the other hand, infection from B. trehalosi bacterium strains leads severe pasteurellosis in lambs and yeanlings. M. haemolytica and B. trehalosi strains share a common antigen system. Earlier both strains were thought to be variants of Pasteurella haemolytica strain. According to the polysaccharide antigens, 17 different serotypes were known. Now the M. haemolytica strain consists of 12, the B. trehalosi strain consists of 4 different serotypes. The serotype A11 is considered a different strain: Mannheimia varigena. The aim of this study is to investigate the occurrence of the different M. haemolytica and B. trehalosi serotypes in Hungary.

Materials and method:

Experimental samples were taken from living infected animals, or aquired through forensic examinations. The samples were taken from 27 sheep, 23 cattle and 2 goats. Bacterium strains were isolated mainly from nasal phlegm, or lung tissue samples. After morphologic and biochemical identification, isolated bacteria were stored under -80 °C, until further analysis. Anti-polysaccharide antibodies were produced in rabbit, and were used for the identification of the strains. Serotypes were identified by passive hemagglutination. We aimed to find the most frequent M. haemolytica and B. trehalosi serotypes iní Hungary.

Results:

Total 52 samples of Mannheimia haemolytica, or Bibersteinia trehalosi the tissue samples were identified after morphological and biochemical examintaions. 12 serotypes were identified trough hemagglutination. In 10 cases the serotype identifocation wasn’t successful. The serotypes occurred in cattle lung tissue samples: A1: 3 times, A2: 5 times, T15: 1 time. Only one strain, A5 was identified from an uterus sample. From cattle nasal wad the following serotypes were identified: A2: 6 times, A7: 1 time. In three cases we couldn’t identify the bacterial serotype. The serotypes in sheep lung tissue samples: A1, A2, A5, A6, A7, A8, A13 occuredred 1 time each, from nasal wad: A6 and A8: 5 times each, A11: 2 times, A2, A9, A13, A17 in 1 time each, 4 strains weren’t identified. Both goat lung tissue samples were contaminated by bacteria from the A2 serotype.

Conclusions:

Further sample analysis is needed to validate our results, for vaccine creation, and to determine the role and impact of the less frequent serotypes.



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