Morphological and Molecular Characterization of a New Mycobacterium avium Subsp. paratuberculosis S-Type Strain Genotype in Goats

Abstract

Paratuberculosis is a chronic bacterial disease of global importance mainly in domestic and wild ruminants, caused by Mycobacterium avium subsp. paratuberculosis (MAP). In goats, paratuberculosis is mostly caused by the “C-type” (cattle) and in a few cases by the “S-type” (sheep) strain of MAP. In 2017, a caprine S-type III isolate with a new VNTR profile was identified in a Swiss alpine region. In 2018, new caprine isolates with the same novel VNTR profile originating from a farm of a close by neighboring valley were analyzed. Here we report on this MAP S-type III outbreak in a Swiss dairy goat farm in which we investigated the pathological changes, distribution and genotype of MAP tissue homogenates. Full necropsy and histological examination were undertaken on two female adult goats with a history of weight loss and intermitting diarrhea. Routine and special stains were applied to characterize the morphological changes. DNA was extracted from 33 different tissue samples and tested for MAP by qPCR targeting IS 900 and F57. Subtyping was performed, using the variable number tandem repeats (VNTR) and mycobacterial interspersed repetitive units (MIRU) approach. The goats showed moderate to marked emaciation and displayed typical clinical features of paratuberculosis. A moderate granulomatous enteritis and regional lymphadenitis with a small to moderate number of acid-fast bacteria within macrophages was detected. MAP detection was mainly restricted to the gastrointestinal tract, mesenteric and hepatic lymph nodes. Subtyping the S-type isolates using a panel of eight established MIRU-VNTR loci identified a new genotype, INMV 218.

Molecular Diversity of Mycobacterium avium subsp. paratuberculosis in Four Dairy Goat Herds from Thuringia (Germany)

“…The current study focused on C-type strains using solid HEYM medium with Mycobactin J for MAP isolation, which is less sensitive for isolation of S-type strains [67,68]. In studies characterizing MAP isolates or MAP-DNA from goats in Spain, Mexico, Canada, and Switzerland, the detected predominant type was also the C-type; however, S-type strains/genomes (Type I/III) were also identified [41,[69][70][71]. The goat herds tested were infected either by C-type or S-type strain(s) only [41], or both types were identified in one herd [70].…”

Strain diversity in Mycobacterium avium subsp. paratuberculosis-positive bovine fecal samples collected in Switzerland

“…This kind of animal movement favors the transmission of different MAP strains between herds and wildlife. In a previous study, morphological and molecular characterization of a new S-type III MAP strain (INMV 218) was described in goats ( 20 ). In comparison to the herein identified S-type III MAP types INMV 72 and INMV 253, differences could be observed in locus VNTR 7, finding an imperfect repeat of 1.5 for the earlier analyzed caprine samples versus two and one tandem repeats for profiles INMV 253 and INMV 72, respectively.…”

“…Each sample was investigated for the presence of the F57 gene and IS 900 using an in-house quantitative PCR (qPCR) ( 20 ). Samples were considered MAP-positive, if both two target genes F57 and IS 900 were detected.…”

Johne's disease in two Korean black goats (Capra hircus coreanae) with clinical and subclinical infection: A case report

“…This result is in agreement with that of a previous study on JD-infected Korean black goats ( Kim et al., 2015 ). However, S-type infections in goats are not rare and have been reported in recent studies in Spain and Switzerland ( De Juan et al., 2006 ; Scherrer et al., 2019 ). Therefore, continuous monitoring is required to detect emerging S-type MAP infections in Korean black goats, helping to deepen our understanding of the molecular epidemiology of MAP and providing better control strategies for MAP in the future.…”