Probiotic prophylaxis of ventilator-associated pneumonia: a blinded, randomized, controlled trial

Enteral administration of probiotics may modify the gastrointestinal environment in a manner that preferentially favors the growth of minimally virulent species. It is unknown whether probiotic modification of the upper aerodigestive flora can reduce nosocomial infections.

To determine whether oropharyngeal and gastric administration of Lactobacillus rhamnosus GG can reduce the incidence of ventilator-associated pneumonia (VAP).

We performed a prospective, randomized, double-blind, placebo-controlled trial of 146 mechanically ventilated patients at high risk of developing VAP. Patients were randomly assigned to receive enteral probiotics (n = 68) or an inert inulin-based placebo (n = 70) twice a day in addition to routine care.

Patients treated with Lactobacillus were significantly less likely to develop microbiologically confirmed VAP compared with patients treated with placebo (40.0 vs. 19.1%; P = 0.007). Although patients treated with probiotics had significantly less Clostridium difficile-associated diarrhea than patients treated with placebo (18.6 vs. 5.8%; P = 0.02), the duration of diarrhea per episode was not different between groups (13.2 ± 7.4 vs. 9.8 ± 4.9 d; P = 0.39). Patients treated with probiotics had fewer days of antibiotics prescribed for VAP (8.6 ± 10.3 vs. 5.6 ± 7.8 d; P = 0.05) and for C. difficile-associated diarrhea (2.1 ± 4.8 SD d vs. 0.5 ± 2.3 d; P = 0.02). No adverse events related to probiotic administration were identified.

These pilot data suggest that L. rhamnosus GG is safe and efficacious in preventing VAP in a select, high-risk ICU population. Clinical trial registered with www.clinicaltrials.gov (NCT00613795).