Cystic fibrosis pulmonary exacerbations (CF PEx) vary greatly in their severity, their pathogens, and their treatment responses. A failure to return to baseline lung function after treatment may be due to persistent infection or chronic inflammation or both. This constant infection and inflammation are believed to be tightly connected, making it difficult to know the exact reason why some patients fail to respond to treatment. The purpose of this study is to evaluate both infection and inflammation during CF PEx to allow for more personalized approaches to improve lung function responses and better CF PEx outcomes. Subjects will be asked to be in the study if they have CF, are 18 years of age or older, and are starting on IV antibiotics due to worsening lung infection. Subjects will stay in the study for up to 5 years, with visits occurring once a year if hospitalized for a CF PEx. Each visit will have blood, sputum, and urine collected and analyzed for changes in expression of certain genes and proteins. These changes may relate to improvements felt by people living with CF and determine what treatments are most helpful.

Inclusion Criteria:

• CF patients 18 years or older
• hospitalized for IV treatment of an acute pulmonary exacerbation
• not on investigational drugs
• who can provide written consent and are willing to comply with study procedure

Exclusion Criteria:

• 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.

Patients followed by the Colorado Adult CF Center will be eligible. A subject will have a diagnosis of cystic fibrosis, be 18 years or older, and been diagnosed by clinical faculty with a pulmonary exacerbation (PEx) and need to be hospitalized to start on IV antibiotic treatment.