The sponsor decided to stop the study prematurely because of financial issues

The purpose of this study is to assess the clinical efficacy of azithromycin, used as a quorum-sensing blocker, when compared to placebo for preventing or delaying the occurrence of pneumonia in ventilated patients colonized with Pseudomonas aeruginosa.

Inclusion Criteria:

• Male and non pregnant female aged 18 to 75 years
• Patients hospitalized in ICU, under mechanically assisted ventilation expected to be mandatory for 3 days or more
• Reasonable survival chance within next few days with an Apache score 10-25
• Tracheal aspirate found positive for P. aeruginosa
• The subject (or a close family member in case of incompetence) understands the procedure, agrees to participate, and is willing to give written informed consent
• Informed consent must be obtained for all subjects before enrollment in the study, by patient or by a close family member

Exclusion Criteria:

• Poor prognosis as judged by Apache score II score >25
• Pregnant female
• Grossly under-or overweight (BMI<18or >29)
• Ongoing therapy with a macrolide
• Known allergy to any macrolide
• Proven P. aeruginosa pneumonia
• Ongoing anti-pseudomonal therapy with a proven susceptible colonizing strain
• Anticipated short duration of mechanical ventilation (<3 days)
• Known drug interaction that could either decrease efficacy or raise safety concerns
• Severe hepatic failure (type C, score >10 on Child Pugh scale)
• Sick sinus syndrome or long QT syndrome
• Recent donation of blood or participation in another clinical trial within 3 months
• Any situation exposing the patient to higher risk or possibly confounding results