Impact of the administration of probiotics on the incidence of ventilator-associated pneumonia: A meta-analysis of randomized controlled trials*

BACKGROUND: Previous reviews showed no benefit for the administration of probiotics in critically ill patients, but they did not focus on ventilator-associated pneumonia. DESIGN: Meta-analysis of randomized controlled trials comparing probiotics and control in patients undergoing mechanical ventilation and reporting on incidence of ventilator-associated pneumonia. METHODS: PubMed, Scopus, Current Contents, Cochrane Central Register of Controlled Trials, and reference lists were searched. Weighted mean differences, pooled odds ratios, and 95% confidence intervals were calculated, implementing both the Mantel-Haenszel fixed effect and the DerSimonian-Laird random effects model. RESULTS: Five randomized controlled trials were included. Administration of probiotics, compared with control, was beneficial in terms of incidence of ventilator-associated pneumonia (689 patients; fixed effect model: odds ratio, 0.61; 95% confidence interval, 0.41-0.91; random effects model: odds ratio, 0.55, 95% confidence interval, 0.31-0.98), length of intensive care unit stay (fixed effect model: weighted mean difference, -0.99 days; 95% confidence interval, -1.37--0.61), and colonization of the respiratory tract with Pseudomonas aeruginosa (odds ratio, 0.35; 95% confidence interval, 0.13-0.93). However, no difference was revealed between comparators regarding intensive care unit mortality (odds ratio, 0.75; 95% confidence interval, 0.47-1.21), in-hospital mortality (odds ratio, 0.75; 95% confidence interval, 0.46-1.24), duration of mechanical ventilation (weighted mean difference, -0.01 days; 95% confidence interval, -0.31--0.29), and diarrhea (odds ratio, 0.61; 95% confidence interval, 0.28-1.34). CONCLUSION: Administration of probiotics is associated with lower incidence of ventilator-associated pneumonia than control. Given the increasing antimicrobial resistance, this promising strategy deserves consideration in future studies, which should have active surveillance for probiotic-induced diseases.