| Summary: | <p>Abstract</p> <p>Background</p> <p>Animal mycobacterioses are regarded as a potential zoonotic risk and cause economical losses world wide. <it>M. avium </it>subsp. <it>hominissuis </it>is a slow-growing subspecies found in mycobacterial infected humans and pigs and therefore rapid and discriminatory typing methods are needed for epidemiological studies. The genetic similarity of <it>M. avium </it>subsp. <it>hominissuis </it>from human and porcine origins using two different typing methods have not been studied earlier. The objective of this study was to compare the IS<it>1245 </it>RFLP pattern and MIRU-VNTR typing to study the genetic relatedness of <it>M. avium </it>strains isolated from slaughter pigs and humans in Finland with regard to public health aspects.</p> <p>Methods</p> <p>A novel PCR-based genotyping method, variable number tandem repeat (VNTR) typing of eight mycobacterial interspersed repetitive units (MIRUs), was evaluated for its ability to characterize Finnish <it>Mycobacterium avium </it>subsp. <it>hominissuis </it>strains isolated from pigs (n = 16) and humans (n = 13) and the results were compared with those obtained by the conventional IS<it>1245 </it>RFLP method.</p> <p>Results</p> <p>The MIRU-VNTR results showed a discriminatory index (DI) of 0,92 and the IS<it>1245 </it>RFLP resulted in DI 0,98. The combined DI for both methods was 0,98. The MIRU-VNTR test has the advantages of being simple, reproducible, non-subjective, which makes it suitable for large-scale screening of <it>M. avium </it>strains.</p> <p>Conclusions</p> <p>Both typing methods demonstrated a high degree of similarity between the strains of human and porcine origin. The parallel application of the methods adds epidemiological value to the comparison of the strains and their origins. The present approach and results support the hypothesis that there is a common source of <it>M. avium </it>subsp. <it>hominissuis </it>infection for pigs and humans or alternatively one species may be the infective source to the other.</p>
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