Genetic diversity of Mycobacterium avium subspecies paratuberculosis and the influence of strain type on infection and pathogenesis: a review

Abstract

Mycobacterium avium subspecies paratuberculosis (Map) is an important pathogen that causes a chronic, progressive granulomatous enteritis known as Johne’s disease or paratuberculosis. The disease is endemic in many parts of the world and responsible for considerable losses to the livestock and associated industries. Diagnosis and control are problematic, due mostly to the long incubation period of the disease when infected animals show no clinical signs and are difficult to detect, and the ability of the organism to survive and persist in the environment. The existence of phenotypically distinct strains of Map has been known since the 1930s but the genetic differentiation of Map strain types has been challenging and only recent technologies have proven sufficiently discriminative for strain comparisons, tracing the sources of infection and epidemiological studies. It is important to understand the differences that exist between Map strains and how they influence both development and transmission of disease. This information is required to develop improved diagnostics and effective vaccines for controlling Johne’s disease. Here I review the current classification of Map strain types, the sources of the genetic variability within strains, growth characteristics and epidemiological traits associated with strain type and the influence of strain type on infection and pathogenicity.

Exploring MALDI-TOF MS approach for a rapid identification ofMycobacterium aviumssp.paratuberculosisfield isolates

“…All procedures described above were performed under biosafety level-3 (BSL-3) conditions. Although we did not analyse any type S field isolates in this study, liquid medium 7H9 was chosen because this medium supports the growth of both type S and C isolates well, while other solid media, such as Herrold's Egg Yolk Medium supplemented with mycobactin, support the growth of type S isolates poorly (Stevenson 2015).…”

Novel Single Nucleotide Polymorphism-Based Assay for Genotyping Mycobacterium avium subsp. paratuberculosis

“…This panel was chosen to maximize genetic diversity and reduce phylogenetic discovery bias (2), since it comprised isolates with different genotypes (determined by multiplex PFGE and MIRU-VNTR), which were selected from 17 different countries and isolated from 8 different host species. The panel also included isolates representing the major strain types that have been described previously (reviewed by 20,21). The sequence reference numbers are given in Fig.…”

Molecular typing of Mycobacterium avium subsp. paratuberculosis (MAP) isolated from dairy goats in Brazil

“…Type C has a wide range of hosts, is commonly isolated from domestic and wild animals, including non-ruminants (Stevenson, 2015) and is the predominant type in cattle (Dimareli-Malli et al, 2013). In patients affected by Crohn's disease, MAP isolates have also been classified as type C (Stevenson, 2015).…”