Pulmonary exacerbations (PEx) are key events that lead to a decline in health status among CF patients, with many never recovering to baseline health. With the advancement of new CFTR modulators and other therapies increasing the lifespan of those living with CF, it will become increasingly important to have better strategies to manage PEx in order to have better outcomes following treatment. PEx treatment decisions will need to take into consideration the increasing frequency of antimicrobial resistance bacteria and the need to treat multiple types of bacteria at once. The purpose of this study is to analyze sputum samples from CF subjects at the time of PEx in order to identify markers of antimicrobial resistant bacteria and see how those relate to treatment responses. CF patients will be recruited from patients followed by the Adult CF Program at National Jewish Health. Within 48 hours of admission to the hospital for treatment of a PEx, subjects will be enrolled and sputum will be collected. The sputum will be processed and analyzed for the presence of antimicrobial resistant bacteria. These results will be compared to clinical data, such as spirometry and frequency of hospitalizations.

Inclusion Criteria:

• CF patients 18 years or older who are hospitalized for IV treatment of an acute PEx
• Chronically infected with Pseudomonas aeruginosa and/or Staphylococcus aureus
• Can produce sputum
• Can provide written consent
• Willing to comply with study procedure

Exclusion Criteria:

• Subjects who are not colonized with Pseudomonas aeruginosa and/or Staphylococcus aureus
• The presence of a condition or abnormality that, in the opinion of the Principal Investigator, would compromise the safety of the patient or the quality of the data

An eligible subject will be a current patient of the Colorado Adult CF Clinic who is being hospitalized at the onset of IV treatment for a pulmonary exacerbation, as diagnosed by a clinic physician, and who is chronically infected with Pseudomonas aeruginosa and/or Staphylococcus aureus.