TDK conference 2020

Pasteurellosis of sheep and goats, caused by various bacterium species has great economic impact in Hungary. Serotype determination of the strains of Mannheima haemolytica and Bibersteinia trehalosi is very important, beyond epidemiological investigation, as the available vaccines are serotype specific. The aim of our study was to survey the frequency of serotypes currently occurring in Hungary, as well as their distribution in each animal species, and to compare the results with previous studies.

We used active and passive sampling, and collected strains from slaughterhouses (Csapod, Hetes, Hajdúnás, Kardoskút, Dömsöd) and from diagnostic laboratories (Veterinary Diagnostic Directorate Budapest and Debrecen, Veterinary Laboratory Diagnostic Services Ltd., Békéscsaba, University of Veterinary Medicine, Budapest, Department of Pathology, and Department of Epidemiology and Microbiology). A total of 196 M. haemolytica, 15 B. trehalosi and 7 M. glucosida strains were collected from 64 settlements. Altogether 176 strains originated from sheep and 42 goats. From the collected strains 115 originated from lungs, 55 from nasal swabs, 25 from bronchi, 7 from pharynges, 7 from eyes, 4 from parenchymal organs (spleen, liver), 3 from milk samples, 1 from brain, and 1 from an abscess. The serotypes of the isolated strains were determined by passive haemagglutination method, for which hyperimmune sera were produced in domestic rabbits.

In sheep, all serotypes except A14 have been found, while only serotypes A2, A6, T3, T4 and T15 have been isolated from goats. The most frequent serotype of M. haemolytica was A2 (37%), followed by A1 (10%), A6 and A12 (7-7%), A7, A8, A9 (6-6-6%), A5 (4%), A16 (2%), A13, A17 (1-1%). From B. trehalosi samples, the most frequent were serotypes were T4 (47%), T3 and T15 (20-20%), and the rarest was T10 (13%). M. glucosida has been shown in 7 cases. A total of 12% of the M haemolytica strains could not to be serotyped. In these cases the species were confirmed by MALDI-TOF MS.

In the case of M. haemolytica, the frequency of serotype A2, A12, A13, A16, A17 increased, while serotype A1, A5 and A8 decreased, compared to previous data. For B. trehalosi, the frequency of serotype T3 and T4 increased, while T10 and T15 decreased. All serotypes except A13 occurred in pneumonia cases. Serotypes A2, A12, A17, T4 and T15 were also isolated from septicaemic cases, and strains A2, A5 and A7 were found in mastitis samples.