Establishment of a Host-to-Host Transmission Model for subsp. Using and Identification of Colonization-Associated Genes.

subsp. () is a member of the non-tuberculous mycobacteria (NTM), and is a common cause of lung infection in patients with chronic NTM lung conditions. is an environmental bacterium believed to be transmitted from environmental sources. In this work we used a recently developed model in to ask whether can be transmitted from host-to-host, and the bacterial genes associated with host colonization. Infection of was carried out by placing the nematode in cultured with . Bacteria eliminated from the intestines of infected were used to infect naïve nematodes. In parallel experiments, to identify colonization associated genes, a transposon library of was screened for the ability to bind to HEp-2 mucosal cells. Thirty clones were identified and five selected clones with impaired adherence to HEp-2 epithelial cells were used to infect to determine the degree of colonization. It was determined that eliminated from infected were able to colonize a naïve with high efficiency. Thirty of the most adherence-deficient clones obtained from the HEp-2 cell screening were sequenced to identify the location of the transposon. Many of the genes associated with the bacterial cell wall synthesis were shown to be inactivated in the selected mutants. Five out of the 30 bacterial clones were then used to infect . All five mutants had impaired ability to colonize compared with the wild type bacteria (decrease of 1.5-2.0 logs, < 0.05). The limitation of this work is that the model can be used for initial screening, but other more complex systems should be used to confirm the findings. can be used as a model to test for adherence/colonization-associated virulence determinants. All the tested adherence-deficient clones that were examined had impaired ability to colonize the host , and some can be potentially used to prevent colonization.