Comparison of Variable-Number Tandem-Repeat Markers typing and IS1245 Restriction Fragment Length Polymorphism fingerprinting of Mycobacterium avium subsp. hominissuis from human and porcine origins

Abstract

BackgroundAnimal mycobacterioses are regarded as a potential zoonotic risk and cause economical losses world wide. M. avium subsp. hominissuis 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 M. avium subsp. hominissuis from human and porcine origins using two different typing methods have not been studied earlier. The objective of this study was to compare the IS1245 RFLP pattern and MIRU-VNTR typing to study the genetic relatedness of M. avium strains isolated from slaughter pigs and humans in Finland with regard to public health aspects.MethodsA 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 Mycobacterium avium subsp. hominissuis strains isolated from pigs (n = 16) and humans (n = 13) and the results were compared with those obtained by the conventional IS1245 RFLP method.ResultsThe MIRU-VNTR results showed a discriminatory index (DI) of 0,92 and the IS1245 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 M. avium strains.ConclusionsBoth 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 M. avium subsp. hominissuis infection for pigs and humans or alternatively one species may be the infective source to the other.

Mycobacterium aviumsubsp.hominissuisInfection in Swine Associated with Peat Used for Bedding

“…The discriminatory power experienced in the present study is slightly reduced compared to what has been described by others [27, 32, 34]. This could be explained by the epidemiologic link between the isolates, as multiple isolates were retrieved from the same farms and production sites and also from the same pigs.…”

“…Of these, three have showed a low allelic diversity for isolates of M. avium subsp. hominissuis in other studies, while TR3 has been demonstrated as monomorphic also in other studies [17, 26, 32, 35]. The employment of these markers in this MLVA analysis is, therefore, not adding as much information as the more diverse loci, and the tandem repeats could be excluded or replaced with other targets, such as one or more of the tandem repeats used in the MATR-VNTR described by Inagaki et al [26].…”

Tuberculosis in swine co-infected withMycobacterium aviumsubsp.hominissuisandMycobacterium bovisin a cluster from Argentina

“…Loci 47, 292, 10, and 7 were monomorphic, whereas locus X3 was the most polymorphic, as previously suggested [20][21][22]35]. The discriminatory power of the combined MIRU-VNTR was 0·68, lower than those obtained by other researchers 0·80 [22], 0·88 [20], 0·90 [35], and 0·92 [21]. This finding may be explained by the presence of clones in the concentrated production region of Argentina.…”

“…Nowadays, MIRU-VNTR analysis is increasingly used for typing M. avium isolates [18][19][20][21][22]. A panel of eight MIRU-VNTR markers has been identified as a suitable tool to discriminate isolates and to study the genetic variability of the strains within the MAC.…”

Correlation between variable-number tandem-repeat-based genotypes and drug susceptibility in Mycobacterium avium isolates

“…A number of reports have described the genotyping of MAC using various methods, including insertion sequence (IS) 1245 and IS1311 restriction fragment length polymorphism (RFLP)-, pulsed field gel electrophoresis (PFGE)-, and variable-number tandemrepeat (VNTR)-based typing [2,3]. It has recently been demonstrated that VNTR typing is useful to distinguish and classify MAC isolates from clinical specimens and environmental sources [4,5]. Moreover, for VNTR typing of MAC, M. avium tandem repeat (MATR)-VNTR and mycobacterial interspersed repetitive units (MIRU)-VNTR typing methods using variation in the combination of targeted tandem repeat loci have been reported [4,6].…”