A Proof of Concept Study to Detect Urease Producing Bacteria in Lungs Using Aerosolized ¹³C-Urea.

Area of Science:

• Medical Diagnostics
• Respiratory Medicine
• Microbiology

Background:

• Cystic Fibrosis (CF) patients often harbor urease-producing bacteria like Pseudomonas aeruginosa.
• Current diagnostic methods for airway bacteria in CF can be invasive or difficult, especially in young children.

Purpose of the Study:

• To evaluate the safety and feasibility of inhaled 13C-urea for detecting urease-producing bacteria in CF patients.
• To assess the diagnostic potential of measuring 13CO2 in breath after 13C-urea inhalation.

Main Methods:

• A prospective, dose-escalation trial involving healthy adults and adult CF patients colonized with P. aeruginosa.
• Inhaled 13C-urea (20mg and 50mg doses) administered via nebulizer.
• Safety assessed by spirometry and physical exams; breath 13CO2/12CO2 ratios measured serially post-inhalation.

Main Results:

• Inhaled 13C-urea was safe, with no significant changes in spirometry in healthy participants or CF patients.
• Elevated 13CO2/12CO2 delta over baseline (DOB) values observed in CF patients post-inhalation, particularly at 5-10 minutes with the 50mg dose.
• Preliminary data suggest higher DOB values correlate with P. aeruginosa presence.

Conclusions:

• Inhaled 13C-urea is a safe investigational tool for detecting urease-producing bacteria in CF airways.
• Breath 13CO2 monitoring shows potential for non-invasive diagnosis of P. aeruginosa infection in CF.
• Future research should explore this method in pediatric CF populations.