Inclusion Criteria:

• Aged 18 years or older at the time of consent to participate in the study.
• Clinical confirmed diagnosis of CF or NCFB per clinical records and guidelines of the CF Foundation or European Respiratory Society (ERS), respectively, for at least 12 months.
• Positive sputum culture for PA or SA (not both) at screening.
• Forced expiratory volume in 1 second (FEV1) ≥ 50% at screening.

For participants with NCFB:

• Not taking chronic inhaled and/or oral antibiotics at screening.

For participants with CF:

• Taking no or only one chronic inhaled antibiotic on alternating months at screening.
• CF patients taking CFTR channel modulators are permitted in the study.

Exclusion Criteria:

• Currently participating in vaccine studies or interventional studies for respiratory infections/diseases.
• Has been taking systemic antibiotics within 30 days prior to screening.
• Clinically significant and unstable cardiovascular, respiratory, renal, gastrointestinal, hematologic, neurologic, endocrinologic, oncologic, ophthalmologic, musculoskeletal, psychiatric or any other uncontrolled medical illness at screening.
• Underwent lung transplantation.
• Positive sputum culture for PA or SA and for other pathogens (e.g., Burkholderia spp., H. influenzae, S. pneumoniae, etc.) at screening. Participants who are co-colonized with PA and SA or with PA or SA and with other bacteria are also excluded.
• History of positive sputum culture for non-tuberculous mycobacterium within the previous 6 months.
• Any condition for which, in the opinion of the investigator, participation would not be in the best  interest of the participant (e.g., compromise the well-being) or that could prevent, limit, or confound the protocol-specified assessments.
• Any physical abnormality which limits the ability to collect regular sputum specimens.