Abstract: Provided are methods for determining resistance or tolerance of a subject to Mycobacterium avium subspecies paratuberculosis (Map) infection, comprising determining, a presence or absence of a mutation, or the genotype of a single nucleotide polymorphism (SNP) within Map infection linkage disequilibrium region SEQ ID NO:46 that segregates with resistance or tolerance to Map infection, or determining a presence or absence of a mutation or a genotype of a SNP within a Map infection linkage disequilibrium region (SEQ ID NO:1) that is in linkage disequilibrium therewith, and determining, based thereon, susceptibility, resistance or tolerance of the subject to Map infection. In particular aspects, a presence or absence of a mutation, or the genotype of a single nucleotide polymorphism (SNP) within at least one gene selected from the group consisting of HIVEP3; EDN2; and LOC521287 that segregates with resistance or tolerance to Map tissue infection is determined.

Abstract: Provided is a method for culturing Mycobacteria in the presence of a class A lantibiotic, thereby inhibiting or reducing bacterial contamination in the culture, without significantly disadvantageously affecting or retarding mycobacterial growth. Further provided are the Mycobacteria culture produced thereby, methods for detecting Mycobacteria in a biological sample under conditions that reduce bacterial contamination, and for diagnosing a mycobacterial infection in a biological sample from a subject suspected of having such an infection, as well as, kits useful in practicing such methods.