"Mycobacteroides abscessus (MAB) is a rapidly growing bacterium typically found in the environment. In the past two decades, infections caused by MAB have increased globally and recently infections in immunocompetent people has been reported.  Additionally, more than 50% of patients incur treatment failure. Several in vitro models are available for MAB research however, experimental outcomes depend heavily on the medium used. The protocols used for clinical antibiotic susceptibility testing use nutrient-rich mediums and fail to identify which antibiotics will be effective for a pulmonary infection. We hypothesize that transcriptomic profiling of MAB in human sputum samples can be used to evaluate several in vitro models for accuracy and to further delineate the physiological state of MAB within the host. To further our understanding of MAB physiology, we will also employ transposon insertion sequencing (Tn-seq) to evaluate genes and pathways essential for the bacterium’s survival in different environments. "