Few antimicrobials are available to treat ventilated associated pneumonia (VAP) caused by Gram negative multi-resistant (MDR) bacteria. Colimycin often remains the only active antibiotic. The aim of the study is to demonstrate the superiority of nebulized colimycin over intravenous colimycin to treat VAP caused by Gramnegative MDR bacteria.
VAP is the most frequent nosocomial infection in critically ill patients and affects length of stay and cost in Intensive Care Unit. The increased incidence of nosocomial infections caused by MDR bacteria becomes a major health problem worldwide. Nowadays, few antimicrobials are available to treat Gram negative MDR VAP. Colimycin often remains the only active antibiotic. Treating VAP by intravenous (IV) colimycin has two main limitations: risk of renal toxicity and low tissue penetration. Nebulization of colimycin offers the possibility of generating high lung tissue concentrations, rapid bactericidal effects and low systemic accumulation in experimental models. To date however, there is no study comparing clinical effectiveness of nebulized and intravenous colimycin. We make the hypothesis that nebulized colimycin increases the clinical cure rate of VAP caused by Gram negative MDR bacteria compared to IV colimycin. Primary Objective: To demonstrate the superiority of nebulized colimycin over intravenous colimycin for treating VAP caused by Gram-negative MDR bacteria. Secondary Objectives: 1. To compare the microbiological cure rate at end of treatment 2. To compare the VAP recurrence rate after end of treatment 3. To compare the lung superinfection rate after end of treatment 4. To compare 28 day- and 90 day-mortality 5. To compare duration of mechanical ventilation 6. To compare length of ICU stay 7. To compare renal function during colimycin administration 8. To compare side effects resulting from colimycin nebulization and intravenous administration Ancillary study: In some centers, blood samples will be performed to measure colistin peak and trough plasma concentrations Study design: This is a randomized, multicenter, double-blind and phase III study 1. Randomization: Patients are randomly assigned to experimental group or control group: Control group: patients receive simultaneously intravenous colimycin and nebulized placebo. Experimental group: patients receive simultaneously nebulized colimycin and intravenous infusion of placebo. Dosing adjustment is according to renal function for intravenous infusion of colimycin or placebo. 2. Aerosol generation: Nebulization is performed with a vibrating plate nebulizer (Aeroneb® Solo) with following ventilator settings: * Constant flow and volume-controlled mode * Inspiratory/expiratory ratio of 1 * Tidal volume of 6-8 ml/kg * Respiratory frequency of 12-18/min * End-inspiratory pause of 20% To standardize nebulization procedure, a checklist form is completed by the nurse in charge of the patient. 3. Duration of treatment: * 10 days in each group * In intubated patients, weaning test is authorized after 4 days of treatment. If patient is extubated, aerosols are discontinued whereas intravenous infusions are continued (placebo or antibiotic) until day 10 * In tracheostomized patients: 10-day treatment for nebulized and intravenous therapy 4. Combined intravenous administration of other antimicrobials are authorized 5. Serum and microbiological samples * Serum creatinine measured daily from baseline to day 11 * Lower respiratory tract specimens at day 5 and day 11 in intubated patients 6. Survival follow-up at day 28 and 90 days Study population: Adult mechanical ventilated patients with VAP caused by Gram-negative MDR bacteria. Sample size and Power consideration: Data will be analyzed with triangular test. Assuming a clinical cure rate at day 11 of 65% in the group treated with nebulized colimycin and of 45% in the group treated with intravenous colimycin, a mean sample size of 134 patients is required to provide 80% power, with a two-sided type I error rate of 5%. The 90th percentile of the number of patients to include is 196.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
7
administration once, twice or 3 times per day according to renal function
administration once, twice or 3 times per day according to renal function
Nebulization is performed with a vibrating plate nebulizer (Aeroneb® Solo) every 8h
Hôpital Pitié-Salpêtriere
Paris, France
Clinical cure of VAP caused by Gram-negative multidrug resistant bacteria
Clinical cure is defined as: * resolution of clinical and biological signs of infection and improved radiological signs * and modified clinical pulmonary infection score (CPIS) less than 6 * and negative culture of lower respiratory tract specimen or, successful weaning from invasive mechanical ventilation between day 5 and day 11 * patient colonized with the same pathogen in the respiratory tract is considered as cured, if clinical and biological signs of infection resolved, radiological signs improved, CPIS \< 6 and/or successful weaning from invasive mechanical ventilation has been obtained.
Time frame: At end of therapy visit (day11) or before day11 if treatment is considered as failed.
Microbiological cure rate
Time frame: At end of therapy visit (day11) or before day11 if treatment is considered as failed.
VAP recurrence rate
VAP recurrence rate, defined as initial clinical cure of VAP with colimycin at day 11 followed by reappearance of clinical and biological signs of infection, CPIS greater than 6, and significant concentrations of Gram-negative MDR bacteria in lower respiratory tract specimen
Time frame: day 28
Lung superinfection rate
Lung superinfection rate defined as reappearance of VAP caused by pathogens other than Gram-negative MDR bacteria isolated from lower respi¬ratory tract specimens from day 11 to day 28
Time frame: day 11, day 28
Mortality
Time frame: day 28 and day 90
Duration of mechanical ventilation
Time frame: Participants will be followed for the duration of ICU stay, an expected average of 3 weeks
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Nebulization is performed with a vibrating plate nebulizer (Aeroneb® Solo) every 8h
Length of ICU stay
Time frame: Participants will be followed for the duration of ICU stay, an expected average of 2 months
Renal function during colimycin administration
Renal function is assessed by measuring daily serum creatinine during treatment period. Colimycin-induced renal function impairment is defined as an increase in serum creatinine level more than 1.5 times the pretreatment value
Time frame: from Day 1 to Day 11
Side effects resulting from colimycin nebulization
Time frame: from Day 1 to Day 11
Side effects resulting from colimycin intravenous administration
Time frame: from Day 1 to day 28