Non-tuberculous Mycobacterial (NTM) infections are an increasing source of patient morbidity and health care cost. Recent estimates of Mycobacterium avium complex (MAC) disease burden report an annual prevalence increase by 36% in the last 10 years. NTM pulmonary disease is associated with high rates of morbidity and mortality, yet available treatment regimens are reported to result in no clinical or microbiological response in an estimated 8-41% of patients with MAC, and is much higher for patients with Mycobacterium abscessus where the rate is as high as 72%. Currently a limited number of patient and bacterial factors predict the poor response to therapy but include cavitary lung disease, high disease burden as indicated by positive AFB smears at baseline, isolates resistant or with inducible resistance to macrolides, a history of previous treatment among a few others. Due to the limited efficacy of medical therapy and the significant associated morbidity and mortality for some patients with pulmonary NTM disease, surgical resection of affected lung has been suggested as an adjunct to medical therapy. However data on the timing and the actual magnitude of benefit offered by surgery is limited. Most studies have been small case series that reported on outcomes of surgery without comparing these outcomes with outcomes of medical therapy alone. Macrolide resistant NTM carries a significantly worse prognosis than NTM that is sensitive to the drug as determined by in vitro drug susceptibility testing. To date it is not known how the rates of macrolide resistance for NTM are evolving over time. It is likely that with the more prevalent use of these antibiotics for treatment of other respiratory infections, and for the prophylaxis of chronic obstructive pulmonary disease and bronchiectasis exacerbations, that the rates will increase and this may pose an increasing public health threat. Here, the student will carry out a retrospective cohort study of MAC patients through the electronic review of medical records in the Partners HealthCare system. The mentor will apply for and secure IRB approval for the work before the student starts. The student will learn about NTM disease natural history, treatment and outcomes, retrospective study design and elements of how to think about and control for confounding. She will also learn how to search medical records, collect data using an abstraction form, develop an organize a database, and basics or more advanced training on biostatistical data analysis depending on the student's comfort level. The student will also gain experience in the scientific writing of the results.