title: Examination ofMycobacterium aviumsubspeciesparatuberculosismixed genotype infections in dairy animals using a whole genome sequencing approach.
abstract: Many pathogenic mycobacteria are known to cause severe disease in humans and animals.M. aviumsubspeciesparatuberculosis(Map) is the causative agent of Johne's disease-a chronic wasting disease affecting ruminants such as cattle and sheep, responsible for significant economic losses in the dairy and beef industries. Due to the lack of treatment options or effective vaccines, mitigating losses can be difficult. In addition, the early stages ofMapinfection may occur in asymptomatic hosts that continue to shed viable bacteria in their faeces, leading to the infection of other healthy animals. Using multi-locus short sequence repeat (ML-SSR) analysis we previously reported that individual Johne's positive dairy cattle from farms across the island of Newfoundland were infected byMapwith multiple SSR-types simultaneously. The occurrence of multiple mixed genotype infections has the potential to change pathogen and disease dynamics as well as reduce the efficacy of treatments and vaccines. Therefore, we conducted whole genome sequencing (WGS) and single nucleotide polymorphism (SNP) analysis on a subset of these isolates for a more in-depth examination. We also implemented a PCR assay using two discriminatory SNPs and demonstrated the incidence of a mixed infection by three genotypically diverseMapisolates in a single animal. In addition, results show that WGS and SNP analysis can provide a better understanding of the relationship betweenMapisolates from individual and different animals. In the future such studies on the occurrence of mixed genotype infections could potentially lead to the identification of variable pathogenicity of different genotypes and allow for better tracking ofMapisolates for epidemiological studies.
authors.affiliation: Department of Biology, Memorial University of Newfoundland , St. John's , NL , Canada.
authors.forename: Fraser W
authors.initials: FW
authors.lastname: Davidson
authors.affiliation: Faculty of Veterinary Medicine, University of Calgary , Calgary , AB , Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Ahlstrom
authors.affiliation: Faculty of Veterinary Medicine, University of Calgary , Calgary , AB , Canada.
authors.forename: Jeroen
authors.initials: J
authors.lastname: De Buck
authors.affiliation: Department of Biology, Memorial University of Newfoundland , St. John's , NL , Canada.
authors.forename: Hugh G
authors.initials: HG
authors.lastname: Whitney
authors.affiliation: Department of Biology, Memorial University of Newfoundland , St. John's , NL , Canada.
authors.forename: Kapil
authors.initials: K
authors.lastname: Tahlan
keywords: Genome sequencing; M. avium subsp. paratuberculosis; Mixed genotype infection