Effect of probiotics on the incidence of ventilator-associated pneumonia in critically ill patients: a randomized controlled multicenter trial

Purpose: To evaluate the potential preventive effect of probiotics on ventilator-associated pneumonia (VAP). Methods: This was an open-label, randomized, controlled multicenter trial involving 235 critically ill adult patients who were expected to receive mechanical ventilation for >= 48 h. The patients were randomized to receive (1) a probiotics capsule containing live Bacillus subtilis and Enterococcus faecalis (Medilac-S) 0.5 g three times daily through a nasogastric feeding tube plus standard preventive strategies or (2) standard preventive strategies alone, for a maximum of 14 days. The development of VAP was evaluated daily, and throat swabs and gastric aspirate were cultured at baseline and once or twice weekly thereafter. Results: The incidence of microbiologically confirmed VAP in the probiotics group was significantly lower than that in the control patients (36.4 vs. 50.4 %, respectively; P = 0.031). The mean time to develop VAP was significantly longer in the probiotics group than in the control group (10.4 vs. 7.5 days, respectively; P = 0.022). The proportion of patients with acquisition of gastric colonization of potentially pathogenic microorganisms (PPMOs) was lower in the probiotics group (24 %) than the control group (44 %) (P = 0.004). However, the proportion of patients with eradication PPMO colonization on both sites of the oropharynx and stomach were not significantly different between the two groups. The administration of probiotics did not result in any improvement in the incidence of clinically suspected VAP, antimicrobial consumption, duration of mechanical ventilation, mortality and length of hospital stay. Conclusion: Therapy with the probiotic bacteria B. Subtilis and E. faecalis are an effective and safe means for preventing VAP and the acquisition of PPMO colonization in the stomach.