Molecular Characterization of Mycobacterium avium subsp. hominissuis of Two Groups of Lymph Nodes, Being Intradermal Tuberculin or Interferon-Gamma Test Positive and Negative, Isolated from Swiss Cattle at Slaughter

Abstract

Mycobacterium avium subsp. hominissuis (MAH) is an important zoonotic pathogen with raising global health concerns. In humans, MAH is one of the most widespread non-tuberculous mycobacterial species responsible for lung disease. In animals, MAH is frequently isolated from pigs; however, it is also an opportunistic pathogen for other mammals including cattle. To elucidate the genetic diversity of MAH in cattle, a molecular characterization of isolates (n = 26) derived from lymph nodes was performed. Fourteen isolates originated from slaughtered cattle with visible altered lymph nodes at meat inspection, whereas 12 isolates were from lymph nodes without any gross pathological changes of healthy slaughtered cattle. Variable number of tandem repeat (VNTR) analysis was performed at 20 loci to examine genetic differences of isolates and to compare to previously reported VNTR data of human isolates from different countries. Genetic elements IS901, IS1245, IS1311, LSPA17, ITS1 sequevar, and hsp65 code were determined. Interestingly, two bovine MAH isolates harbored ISMav6 and hsp65 code 15, which so far has only been observed in human isolates. We supposed that VNTR data of Swiss samples would show clustering with European samples. Minimum spanning tree and unweighted pair group method using arithmetic averages analyses based on the VNTR data indicated a specific cluster of MAH isolates obtained from lymph nodes without any gross pathological changes of healthy slaughtered cattle. Comparing Swiss isolates with isolates from different other countries, no geographical clustering was observed; however, four Swiss isolates had an identical VNTR profile as human isolates from the Netherlands, the United States, and Japan. These findings indicate a possible public health issue.

Comparative Evaluation of Band-Based Genotyping Methods for Mycobacterium intracellulare and Its Application for Epidemiological Analysis

“…In the previous study of the relationship between the M. avium subsp. hominissuis (MAH) genotype and geographic origin, MAH from Japan seemed to be more closely related to the Korean lineage than Europe or the United States [ 23 , 29 ]. However, for M. intracellulare , there is still no reported relationship between geographic origin and genetic characteristics [ 12 , 23 ].…”

Differential Genotyping of Mycobacterium avium Complex and Its Implications in Clinical and Environmental Epidemiology

“…The association between animal and human isolates was also investigated. In the VNTR genotyping analysis using MATR and MIRU loci, some MAH Swiss isolates from bovine lymph nodes were similar to the pulmonary patient isolates from Netherlands, United States, and Japan [87]. The ISMav6 gene, which is distributed predominantly among isolates obtained from a patient in East Asian regions, was first found in isolates obtained from animals, indicating a close genetic association between the human and animal strains [87].…”

“…In the VNTR genotyping analysis using MATR and MIRU loci, some MAH Swiss isolates from bovine lymph nodes were similar to the pulmonary patient isolates from Netherlands, United States, and Japan [87]. The ISMav6 gene, which is distributed predominantly among isolates obtained from a patient in East Asian regions, was first found in isolates obtained from animals, indicating a close genetic association between the human and animal strains [87]. Additionally, a comparison of VNTR types analyzed using MIRU and MATR loci in previous studies of MANT BVLA01 strains isolated from cattle showed a close relationship between isolates obtained from Japanese patients and from the bathtub [88].…”

The Mycobacterium avium complex – an underestimated threat to humans and animals

“…The tissue changes caused by MAC bacteria in cattle are indistinguishable from those caused by MTC bacteria, which may make diagnosis difficult. Granulomatous lesions are mainly located in the lymph nodes of the gastrointestinal and respiratory systems, although there have been cases of systemic disease [57,70,71]. Ruminants are most often infected by MAP, resulting in chronic inflammation of the intestines, called Johne's disease or paratuberculosis.…”