Distribution of Mycobacterium avium subsp. avium and M. a. hominissuis in artificially infected pigs studied by culture and IS901 and IS1245 quantitative real time PCR

Mycobacterium avium subsp. avium (MAA) and M. a. hominissuis (MAH) belong to the Mycobacterium avium complex (MAC) and are frequently associated with diseases in animals and humans. The aim of this study was to develop a system for rapid and accurate real time quantitative PCR (qPCR) identification and quantification of MAA and MAH. This study included 22 per os infected pigs, of which 10 were infected with MAA, 10 with MAH and 2 were present as a negative control group. From each animal, 21 different tissue samples as well as blood were tested by microscopy, culture and triplex qPCR. The developed triplex qPCR reaction was based on the simultaneous detection of specific insertion sequences, IS901 and IS1245, and also contained an internal amplification control. In both groups of experimentally infected animals, the newly developed triplex qPCR assay proved to be more specific and sensitive in comparison with the other methods used. Contrary to culture examination, triplex qPCR confirmed the infection in all animals infected with MAA, and in eight animals infected with MAH. In conclusion, we developed a quick and sufficiently sensitive triplex qPCR for MAA and MAH detection in tissue and blood samples. From the food safety point of view the presence of MAH in muscles should be considered as a possible threat to human health.