Article Azithromycin to prevent Pseudomonas aeruginosa ventilator-associated pneumonia by inhibition of quorum sensing: a randomized controlled trial VAN DELDEN, Christian, et al. Abstract Anti-virulence strategies have not been evaluated for the prevention of bacterial infections. Prolonged colonization of intubated patients with Pseudomonas aeruginosa isolates producing high-levels of the quorum sensing (QS)-regulated virulence factor rhamnolipids has been associated with ventilator-associated pneumonia (VAP). In this pathogen, azithromycin reduces QS-regulated virulence. We aimed to assess whether azithromycin could prevent VAP in patients colonized by rhamnolipids producing isolates. Reference VAN DELDEN, Christian, et al. Azithromycin to prevent Pseudomonas aeruginosa ventilator-associated pneumonia by inhibition of quorum sensing: a randomized controlled trial. Intensive Care Medicine, 2012, vol. 38, no. 7, p. 1118-25 DOI : 10.1007/s00134-012-2559-3 PMID : 22527075 Available at: http://archive-ouverte.unige.ch/unige:32040 Disclaimer: layout of this document may differ from the published version. 1 / 1 Intensive Care Med (2012) 38:1118–1125 DOI 10.1007/s00134-012-2559-3 ORIGINAL Christian van Delden Azithromycin to prevent Pseudomonas Thilo Ko¨hler Franc¸oise Brunner-Ferber aeruginosa ventilator-associated pneumonia Bruno Franc¸ois Jean Carlet by inhibition of quorum sensing: a randomized Jean-Claude Peche`re controlled trial F. Brunner-Ferber at the highest risk to develop VAP Received: 8 June 2011 Brunner Naga, Pfaeffikon-ZH, Accepted: 29 February 2012 linked to this QS-dependent virulence Switzerland Published online: 20 April 2012 factor. Results: Ninety-two patients Ó Copyright jointly held by Springer and were enrolled; 43 azithromycin-trea- ESICM 2012 B. Franc¸ois Intensive Care Unit, CIC-P 0801 Inserm, ted and 42 placebo patients were Presented in part at the ICAAC meeting Dupuytren Hospital Limoges, eligible for the per-protocol analysis. 2010 Boston. Limoges, France In the per-protocol population, the occurrence of P. aeruginosa VAP This article is discussed in the editorial J. Carlet was reduced in the azithromycin available at: Groupe Hospitalier Saint Joseph, doi:10.1007/s00134-012-2561-9. group but without reaching statistical Paris, France significance (4.7 vs. 14.3 % VAP, J.-C. Peche`re: Deceased 29th November 2008. p = 0.156). QS-dependent virulence Abstract Purpose: Anti-virulence of colonizing isolates was similarly Electronic supplementary material strategies have not been evaluated for low in both study groups, and only The online version of this article the prevention of bacterial infections. five patients in each arm were per- (doi:10.1007/s00134-012-2559-3) contains supplementary material, which is available Prolonged colonization of intubated sistently colonized by high-level to authorized users. patients with Pseudomonas aerugin- rhamnolipids producing isolates. In osa isolates producing high-levels of this high-risk subgroup, the incidence the quorum sensing (QS)-regulated of VAP was reduced fivefold in virulence factor rhamnolipids has azithromycin versus placebo patients been associated with ventilator-asso- (1/5 vs. 5/5 VAP, p = 0.048). Con- ciated pneumonia (VAP). In this clusions: There was a trend towards pathogen, azithromycin reduces QS- reduced incidence of VAP in colo- regulated virulence. We aimed to nized azithromycin-treated patients. C. van Delden ()) Á T. Ko¨hler assess whether azithromycin could In addition, azithromycin signifi- Service of Infectious Diseases, prevent VAP in patients colonized by cantly prevented VAP in those University Hospital Geneva, 4 Rue Gabrielle-Perret-Gentil, rhamnolipids producing isolates. patients at high risk of rhamnolipid- 1211 Geneva, Switzerland Methods: In a randomized, double- dependent VAP, suggesting that vir- e-mail: [email protected] blind, multicenter trial, intubated ulence inhibition is a promising anti- Tel.: ?41-22-3723207 colonized patients received either microbial strategy. Fax: ?41-22-3727863 300 mg/day azithromycin or placebo. Primary endpoint was the occurrence Keywords Pseudomonas C. van Delden Á T. Ko¨hler Á J.-C. Peche`re of P. aeruginosa VAP. We further aeruginosa Á Ventilator-associated Department of Microbiology and Molecular Medicine, identified those patients persistently pneumonia Á Virulence Á Quorum University of Geneva, colonized by isolates producing high- sensing Á Rhamnolipids Geneva, Switzerland levels of rhamnolipids and therefore 1119 Introduction documented colonization in bronchial aspirates at study entry. We obtained approval for this multicenter European Multi-drug-resistant bacteria represent a major medical study by the respective local ethics committees and national threat, contributing to the deaths of increasing numbers of agencies. Written consent from all patients or their legal patients worldwide. To face this serious challenge, alter- representatives was obtained according to legal and ethical native strategies aiming at the inhibition of bacterial considerations. The study took place between November virulence have been proposed [1]. Due to the absence of 2002 and November 2005. Twenty-one European centers selective pressure, such strategies are believed to mini- participated in this trial; eight in France, four in Spain, two in mize the risk of emergence of resistant clones [2, 3]. To Belgium, three in Poland, two in Serbia, and two in Swit- our knowledge, however, no clinical study has demon- zerland. We screened mechanically ventilated patients for strated the feasibility of such an approach. respiratory tract colonization by P. aeruginosa on alternate Pseudomonas aeruginosa is a leading cause of venti- days. Eligible patients were adults between 18 and 75 years lator-associated pneumonia (VAP) [4–6]. This pathogen of age, hospitalized in the ICU under mechanical ventilation frequently develops resistance to available antimicrobial expected to be required for at least 3 days, with a reasonable agents [7–9]. Improved treatments and/or preventive surviving chance (Apache score between 10 and 25), and measures are urgently required since attributable mortal- proven to be colonized by P. aeruginosa. Neutropenic ity of this condition remains high [6]. Whereas almost all patients and patients treated with immunosuppressive drugs cases of P. aeruginosa-associated VAP are preceded by were not eligible. Patients with ongoing P. aeruginosa colonization of the respiratory tract, only 10–20 % of infection, having received macrolides or antibiotics active colonized patients eventually evolve to VAP [4]. Quorum against the colonizing P. aeruginosa isolate during the last sensing (QS) is a complex signaling network that allows 14 days were excluded. Patients with proven colonization coordinated gene expression according to cell density [1] by P. aeruginosa were randomized (D-1) and received and regulates many major virulence factors in P. aeru- either placebo or 300 mg per day iv azithromycin in a ginosa [10]. As a consequence, QS is an ideal target for double-blind fashion for a maximum of 20 days (D1 to Dx). anti-virulence strategies. Macrolides, like azithromycin, The 300-mg dose was selected taking into account a bio- are neither bactericidal nor bacteriostatic for P. aerugin- availability of 37 % of the usual 500-mg oral dose, the need osa at clinically achievable concentrations and are for reaching steady state at lung level within 3 days, and therefore unlikely to select resistant clones. However, at safety considerations. these concentrations, azithromycin inhibits QS in vitro During the study, the administration of antibiotics [11–14]. Furthermore, we have shown that azithromycin proven to be inactive against the isolated P. aeruginosa reduces the expression of QS-circuit and target genes in strains was allowed without restrictions. The adminis- patient [15]. Azithromycin has a favorable profile in tration of antibiotics with intrinsic activity against terms of pharmacokinetics and of metabolism. Lung tis- P. aeruginosa strains was only allowed if considered as sue distribution is high, enabling to reach QS-inhibitory mandatory. The prophylaxis study period was restricted to concentrations (2–4 lg/ml) in bronchial mucosa, epithe- a maximum of 20 days, and reasons for early discontin- lial lining fluid, and sputum after a single 500-mg dose uation included extubation, death, serious adverse events, [16]. No clinical trial has previously investigated a viru- or suspected P. aeruginosa VAP. The diagnosis of lence inhibition strategy for the prevention of bacterial P. aeruginosa VAP was based on the clinical picture, infections. Thus, we decided to conduct a proof-of-con- X-ray scan, a pulmonary infection score (CPIS) C6, as cept study, designed as a multicenter, randomized, well as a quantitative culture of a bronchoalveolar lavage double-blind, placebo-controlled trial to evaluate azith- fluid (BAL) yielding [104 CFU/ml P. aeruginosa, in the romycin for the prevention of P. aeruginosa VAP in absence of other pathogenic bacterial species [17, 18]. An colonized mechanically ventilated patients. independent panel of three experts blinded to treatment confirmed the P. aeruginosa VAP cases. Methods Clinical sample collection Study population Starting the first day of proven colonization (D-1), daily tracheal aspirates (usually 0.3–5 ml) and P. aeruginosa This pilot, randomized, placebo-controlled, double-blind strains were collected during the entire study period. study (ANB 006#2001, ClinicalTrials.gov