Genome-Wide Analysis of the Emerging Infection with Mycobacterium avium Subspecies paratuberculosis in the Arabian Camels (Camelus dromedarius)

Abstract

Mycobacterium avium subspecies paratuberculosis ( M. ap ) is the causative agent of paratuberculosis or Johne's disease (JD) in herbivores with potential involvement in cases of Crohn's disease in humans. JD is spread worldwide and is economically important for both beef and dairy industries. Generally, pathogenic ovine strains ( M. ap -S) are mainly found in sheep while bovine strains ( M. ap -C) infect other ruminants (e.g. cattle, goat, deer), as well as sheep. In an effort to characterize this emerging infection in dromedary/Arabian camels, we successfully cultured M. ap from several samples collected from infected camels suffering from chronic, intermittent diarrhea suggestive of JD. Gene-based typing of isolates indicated that all isolates belong to sheep lineage of strains of M. ap ( M. ap -S), suggesting a putative transmission from infected sheep herds. Screening sheep and goat herds associated with camels identified the circulation of this type in sheep but not goats. The current genome-wide analysis recognizes these camel isolates as a sub-lineage of the sheep strain with a significant number of single nucleotide polymorphisms (SNPs) between sheep and camel isolates (∼1000 SNPs). Such polymorphism could represent geographical differences among isolates or host adaptation of M. ap during camel infection. To our knowledge, this is the first attempt to examine the genomic basis of this emerging infection in camels with implications on the evolution of this important pathogen. The sequenced genomes of M. ap isolates from camels will further assist our efforts to understand JD pathogenesis and the dynamic of disease transmission across animal species.

Superior Protection from Live-Attenuated Vaccines Directed against Johne's Disease

“…The live-attenuated vaccine candidates, the pgsH and pgsN vaccine constructs, were created by homologous recombination, as previously described (16,17). The experimental vaccines were grown in 7H9 liquid medium supplemented with 0.5% glycerol, 2 g/ml mycobactin J (Allied Monitor, Fayette, MO), and 10% ADC (2% glucose, 5% bovine serum albumin fraction V, and 0.85% NaCl) (30). All bacterial cultures were freshly cultivated for 8 to 12 weeks and never refrigerated or frozen prior to use.…”

“…Environmental and individual fecal samples collected from goats were processed using a previously described sedimentation method with minor variations in an attempt to optimize M. paratuberculosis recovery (30). Briefly, 3 g of each fecal sample was weighed and homogenized with 30 ml of 0.75% hexadecyl pyridinium chloride (HPC) (Sigma-Aldrich, St. Louis, MO) overnight to reduce nonmycobacterial contaminants.…”

“…Each specimen was trimmed and weighed to 2 g, placed in Whirl-Pak bags with 10 ml of PBS, and homogenized in a Seward stomacher for 10 min on high. For plating, a 0.1-ml aliquot of the fecal supernatants and tissue homogenates (as well as a 1:10 dilution of the homogenates) was plated on Middlebrook 7H10 agar supplemented with 0.5% glycerol, 2 g/ml mycobactin J (Allied Monitor), and 10% ADC (30). Additional antibiotic supplementation with amphotericin B (50 g/ml), vancomycin (100 g/ml), and nalidixic acid (100 g/ml) was used to prevent nonmycobacterial contamination.…”

Key Role for the Alternative Sigma Factor, SigH, in the Intracellular Life of Mycobacterium avium subsp. paratuberculosis during Macrophage Stress

“…paratuberculosis is the etiological agent of Johne's disease (JD), a chronic enteritis of domestic and wild animals, especially ruminants. JD has been reported on every continent (1)(2)(3) and is considered one of the greatest causes of economic hardship to the dairy herd operations (4). More than two thirds of the U.S. dairy herds are infected with JD (5), and this wide distribution of the disease, reduced milk production, and premature culling of infected animals together cause severe economic losses estimated to be over $200 million a year for the dairy industry (6).…”

Viable Mycobacterium avium ssp. paratuberculosis isolated from calf milk replacer

“…The consensus sequence of each sample was then extracted from CLCBio software and used to build a phylogenetic tree using HarvestTools (Treangen et al, 2014). Finally, to distinguish MAP genotypes (type I vs. II or III), hsp65, gyrA, and gyrB PCR followed by enzyme digestion were performed as detailed previously by Castellanos et al (2007) and Ghosh et al (2012).…”