EN
Laboratory diagnosis of swine dysentery (SD) and proliferative enteropathy (PE) by standard bacteriological methods is time consuming and bears the risk of false negative results. Limitations concerning the isolation of L. intracellularis and difficulties with conventional bacteriological procedures were the primary reasons for developing a PCR for the diagnosis of PE and SD. The aim of this study was to develop a multiplex PCR for the detection of B. hyodysenteriae and L. intracellularis and to determine the usefulness of this technique in diagnosing the above mentioned diseases. The investigations were evaluated on strains of B. hyodysenteriae B204 and the bacterial filtrate of L. intracellularis. In order to determine the sensitivity of multiplex PCR from bacterial suspension (B. hyodysenteriae 2 × 108 cfu/ml) and (L. intracellularis - 1.1 × 106 cfu/ml) 10-fold dilutions were prepared in a Tris-HCl, pH 8.5 buffer or in supernatant of swine feces in Tris-HCl, pH 8.5 buffer. The elaborated multiplex PCR was able to detect 1.1 × 104 cfu/ml L. intracellularis and 2 × 105 cfu/ml B. hyodysenteriae. In analyzing the sensitivity of multiplex PCR in the presence of the two mentioned species of bacteria in feces it was assumed that the presence of a 2000 times greater number of B. hyodysenteriae cells in fecal sample than L. intracellularis did not decrease the sensitivity of multiplex PCR in the detection of L. intracellularis. At the same time about a two times higher amount of L. intracellularis cells than B. hyodysenteriae decreased the sensitivity of multiplex PCR for the detection of B. hyodysenteriae by 200 times. However the presence of porcine feces which contain inhibitory factors decreased the detection of L. intracellularis. Amplification of extracted DNA from feces suspension gave a 100 times lower sensitivity than amplification of extracted DNA from Tris-HCl, pH 8.5 buffer with the same number of CFU/ml L. intracellularis. On the other hand sensitivity of the method was satisfying even if the number of B. hyodysenteriae cells was 2000 times higher. The results proved that multiplex PCR for the detection of B. hyodysenteriae was not susceptible to inhibitory substances, however twice as high a number of L. intracellularis cells than B. hyodysenteriae in a sample hampered the amplification specific to B. hyodysenteriae. The results of this study demonstrated that multiplex PCR is useful for the detection of L. intracellularis. In case of an intensive infection of pigs by both pathogens multiplex PCR has limitations in the diagnosis of B. hyodysenteriae.