Figure 1.

Flowchart of patient selection. A logging system containing the medical record numbers of all patients between 1996 and 2017 at the University of Iowa Hospitals and Clinics with cultures positive for Mycobacterium tuberculous or nontuberculous mycobacteria (NTM) was reviewed. Medical record review was performed on all patients with cultures positive for NTM or Mycobacterium bovis. Infection was defined using the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) NTM lung disease guidelines. Contaminant was defined as a single positive culture without clinical or radiographic evidence of disease. Colonization was defined as ≥2 positive cultures without clinical or radiographic evidence of disease. Cases were excluded if medical records lacked sufficient information to diagnose infection according to ATS/IDSA guidelines. Cases of chronic NTM infection with multiple positive cultures were included only once in data analysis.