TDK conference 2014

Actinobacillus pleuropneumoniae is the causative agent of hemorrhagic-necrotic pneumonia and fibrinous pleuritis of swine throughout the world. The bacterium is a Gram negative, facultative anaerobic, fastidious and facultative pathogenic one, it is present on the mucous membrane of the respiratory tract of swine and can cause disease in case of different predisposing factors in growing pigs. The disease can be peracut, acute and chronic and the typical clinical signs and pathological lesions help the diagnosis.

On the basis of NAD requirement for growth A. pleuropneumoniae biotype 1 (NAD-dependent) and biotype 2 (NAD-independent) can be distinguished. After combining the previous typing systems 15 serotypes can be differentiated.

The aim of the study was serotyping recently isolated A. pleuropneumoniae strains and the previously non typable strains from the culture collection of the Department of Microbiology and Infectious Diseases. According to the biochemical and cultural properties all strains were classified as NAD-dependent biotype 1 ones. In order to compare the results, serotyping was carried out by indirect haemagglutination test and molecular biological (PCR) methods.

None of our strains showed positive reaction with antisera produced against type strains, they were regarded non typable, but they showed positive reactions with the antisera raised against them. According to the PCR test based on detection of toxin genes, the strains belong to the 5a/5b serotypes. These two serotypes cannot be differentiated on the basis of the toxin profile, since only four groups of serotypes can be differentiated in this method, due to cross-reactions.

According to the results of isolates seem to represent a new serotype.