Probiotics for disease prevention: a focus on ventilator-associated pneumonia

To summarize published data regarding the safety and efficacy of probiotics in the prevention of ventilator-associated pneumonia (VAP).

PubMed databases (January 2000-August 2011) were searched and a bibliographic review of published articles was performed to identify original reports of probiotic administration for the prevention of VAP using the search terms probiotics, synbiotics, and ventilator-associated pneumonia.

Two pilot studies, 2 randomized controlled trials (RCTs), and 1 meta-analysis have addressed probiotic use for VAP prevention and were included in the review.

VAP frequently occurs in mechanically ventilated patients. Given the lack of new antimicrobial agents, probiotics have been studied for their ability to modify human microflora colonization. Two studies examining pathogen colonization rates favored probiotics, with reduced incidence and increased duration until the emergence of new species. One prospective RCT found significant reduction in the incidence of VAP and colonization rates, but no significant difference in patient disposition outcomes. Another RCT examining 28-day mortality found no overall benefit with probiotic use and no reduction in colonization rates.

Clinical trials have failed to demonstrate a consistent beneficial effect of probiotics in mechanically ventilated patients; thus, they are not recommended for routine clinical use. However, heterogeneity among study designs may hinder this assessment and the designs should be unified in future research.