Genetic diversity ofMycobacterium aviumcomplex strains isolated in Argentina by MIRU-VNTR

Abstract

Mycobacterium avium sp. avium (MAA), M. avium sp. hominissuis (MAH), and M. avium sp. paratuberculosis (MAP) are the main members of the M. avium complex (MAC) causing diseases in several hosts. The aim of this study was to describe the genetic diversity of MAC isolated from different hosts. Twenty-six MAH and 61 MAP isolates were recovered from humans and cattle, respectively. GenoType CM® and IS1311-PCR were used to identify Mycobacterium species. The IS901-PCR was used to differentiate between MAH and MAA, while IS900-PCR was used to identify MAP. Genotyping was performed using a mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) scheme (loci: 292, X3, 25, 47, 3, 7, 10, 32) and patterns (INMV) were assigned according to the MAC-INMV database (http://mac-inmv.tours.inra.fr/). Twenty-two (22/26, 84·6%) MAH isolates were genotyped and 16 were grouped into the following, INMV 92, INMV 121, INMV 97, INMV 103, INMV 50, and INMV 40. The loci X3 and 25 showed the largest diversity (D: 0·5844), and the global discriminatory index (Hunter and Gaston discriminatory index, HGDI) was 0·9300. MAP (100%) isolates were grouped into INMV 1, INMV 2, INMV 11, INMV 8, and INMV 5. The HGDI was 0·6984 and loci 292 and 7 had the largest D (0·6980 and 0·5050). MAH presented a higher D when compared with MAP. The MIRU-VNTR was a useful tool to describe the genetic diversity of both MAH and MAP as well as to identify six new MAH patterns that were conveniently reported to the MAC-INMV database. It was also demonstrated that, in the geographical region studied, human MAC cases were produced by MAH as there was no MAA found among the human clinical samples.

GENETIC DIVERSITY OF MYCOBACTERIUM AVIUM subsp. HOMINISSUIS STRAINS ISOLATED IN ITALY BASED ON VNTR LOCI ANALYSIS

“…The VNTR typing assay employed in the present study showed that 5 VNTR loci of our MAH iso-lates (i.e., loci 32, 292, X3, 25 and 47) were enough polymorphic to yield an acceptable allelic diversity. Indeed, in agreement with previous reports [4,10,12,17,18], locus VNTR X3 turn out to be the most polymorphic, while loci VNTR 3, VNTR 7 and VNTR 10 were the least suitable for VNTR typing of MAH isolates. Our VNTR analysis, that yielded 25 unique VNTR patterns and identified 12 clusters including a total 95 isolates, showed an excellent discriminatory power (HGDI = 0.990), similar to that obtained with VNTR schemes used by other authors [4,5].…”

“…Indeed, in agreement with previous reports [4,10,12,17,18], locus VNTR X3 turn out to be the most polymorphic, while loci VNTR 3, VNTR 7 and VNTR 10 were the least suitable for VNTR typing of MAH isolates. Our VNTR analysis, that yielded 25 unique VNTR patterns and identified 12 clusters including a total 95 isolates, showed an excellent discriminatory power (HGDI = 0.990), similar to that obtained with VNTR schemes used by other authors [4,5]. The results obtained through the VNTR analysis showed that most MAH strains displayed a close genetic relationship, as indicated by the minimum spanning tree analysis; in fact, 21 out of 25 VNTR patterns of the MAH isolates, occurring either as clustered or unique isolates, differed from the nearest one only for one allelic variation.…”

Systemic mycobacteriosis caused by ‘<i>Mycobacterium avium</i> subspecies <i>hominissuis</i>’ in a 14-month-old Japanese black beef steer

“…In cattle, MAC has been mostly isolated at slaughterhouses in Europe [ 3 ], Africa [ 24 ] and South America [ 11 ], serving as an early warning for Asian countries. Previous reports were concerned with the epidemiology and bacteriology of the affected cattle, but descriptions were short and limited.…”

“…Previous reports were concerned with the epidemiology and bacteriology of the affected cattle, but descriptions were short and limited. Furthermore, histopathological examinations were not performed in the previous studies [ 3 , 11 , 24 ]. Therefore, there is limited information on systemic Mah infection in cattle and the expression of clinical symptoms.…”

“…In previous studies on bovine Mah infection, only epidemiological and bacteriological examinations were conducted, and provided limited histopathological information [ 3 , 11 , 24 ]. Moreover, immunohistochemical identification of the Mycobacterium antigen was not performed [ 3 , 11 , 24 ]. Our immunohistochemical and bacteriological findings indicated that the systemic granulomatous lesions were closely associated with Mah .…”