Evaluation of Inhaled Antibiotics on Bacterial Diversity and Richness in the Cystic Fibrosis Lung

Comparative Evaluation of Bacterial Diversity and Richness in CF Lung in Patients Who Use Cycled Every Other Month Tobramycin Inhalation Powder (TOBI™ Podhaler™) Or Continuous Alternating Therapy With Tobramycin Inhalation Powder (TOBI™ Podhaler™) and Inhaled Colistimethate

The purpose of this study is to characterize bacterial diversity and richness in the sputum of cystic fibrosis patients treated with every-other-month TOBI™ Podhaler™ and continuous alternating therapy with TOBI™ Podhaler and colistimethate (Colistin).

Inclusion Criteria:

• Diagnosis of cystic fibrosis confirmed by mutation analysis of the cystic fibrosis transmembrane conductance regulator gene
• Sputum or throat swab culture positive for Pseudomonas aeruginosa at or within 6 months of enrollment
• Age ≥12 years
• Forced expiratory volume in one second (FEV1) 25-90 percent-predicted

Exclusion Criteria:

• Age <18 years
• Inability to routinely expectorate sputum without induction by hypertonic saline
• Inability to provide or withdrawal of written informed consent
• History of aminoglycoside sensitivity or adverse reaction to inhaled antibiotics
• Serum creatinine ≥ 2.0 mg/dl
• Serum blood urea nitrogen (BUN) ≥40 mg/dl
• Pregnancy or lactating at screening
• History of systemic intravenous anti-Pseudomonal antibiotics within 28 days of enrollment