Jánosi - Állatorvostudományi Doktori Iskola - Szent István Egyetem ...

2. Summary
The author carried out the comparative examination of H. somni strains isolated from farm animals.
She collected 652 swab samples in 9 cattle- and 10 goat flocks of Hungary then isolated 56 bacterial
strains identified as H. somni on the basis of cultural, morphological and biochemical
characteristics. H. somni was found to be present in 10-40% on the genital mucous membranes of
cattle, the isolation rate increased from 40% to 90% during a four-time, monthly sampling of 20
heifers. She reported the first isolation of H. somni from goats.
One hundred H. somni strains from fresh clinical isolates and from the culture collection of
Department of Microbiology and Infectious Diseases (Szent István University, Faculty of
Veterinary Science, Budapest, Hungary) were included in the examinations.
Using the BIOLOG MICROSTATION ID SYSTEM she identified the H. somni strains on the basis of
the utilisation 95 single carbon sources. The system identified 83% of the examined bacterial strains
as H. somni. Compared to the results of 15 H. somni identified by partial amplification of 16S
rDNA, false negative but no false positive ones could be found.
Analysing the metabolic fingerprints of H. somni strains there were two carbon sources – dextrin
and α-D-glucose – that could be utilised by all of the strains. In the case of bovine vaginal isolates
the 100% utilisation ability of D, L-lactic acid was a typical characteristic of the group as well as D-
mannose and turanose were in the case of H. somni strains isolated from sheep.
Studying the relationships of 100 H. somni strains on the dendrogram based on their carbon source
utilisation, she found several highly similar strains as well as different ones in certain cattle and
sheep flocks. She proved the presence of two persistent respiratory isolates in a cattle stock.
Analysing the cumulative results of pulsed field gel electrophoresis (PFGE) she also confirmed the
presence of similar, different and persistent H. somni strains in certain cattle and sheep flocks.
Comparing the results of metabolic fingerprinting and PFGE, the methods completed well each
other. She adopted the first time the examination of carbon source utilisation for epidemiological
characterisation of H. somni strains.
For studying the clinical and pathological effect of H. somni in calves an aerosol infection method
closely resembling the natural way of infection was developed. She applied the method successfully
in infecting calves. Pathological examination of infected and control groups showed catarrhal
bronchopneumonia in all animals, thus histopathological examination to complete pathological
results and evaluate the efficacy of the trial was recommended. In the control group no H. somni
was isolated in contrast the 100% detection rate in infected groups. She characterised the first time
in Hungary the pathological and histological findings of H. somni infected calf lungs.
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