Growth in biofilms prepares Mycobacterium avium susp. hominissuis for the transition to the macrophage microenvironment

Mycobacterium avium subs. hominissuis (MAH) is an opportunistic pathogen, causing pulmonary infections in individuals who are immunocompromised or whose respiratory systems are damaged due to injuries or diseases such as cystic fibrosis, bronchiectasis, or chronic obstructive pulmonary disease. MAH is an environmental microbe commonly found in numerous natural and engineered habitats, including marginal niches where few species are able to survive. MAH is able to persist in these habitats through biofilm formation, a process in which the hydrophobic mycobacterial cells preferentially adhere to a surface or to particles in suspension. The process of biofilm formation as well as the movement of MAH from its environmental niche into a host entails a large shift in conditions and stressors. To mediate these transitions, it is necessary that MAH responds by modulating its gene expression. We used next generation sequencing to define changes in MAH gene expression that occur during biofilm formation and during transition to survival inside host macrophages.