The pathogenesis of ventilator-associated pneumonia (VAP) involves a shift from the host's native, non-pathogenic resident flora, to an opportunistic, ICU-acquired colonizing flora rich in pathogens. This study was undertaken to determine whether restoration of the normal host flora using a commercially available probiotic agent could successfully prevent VAP.
After obtaining informed consent, adult patients expected to require prolonged mechanical ventilation were stratified by APACHE II score and randomized to double-blinded administration of 10(9) CFU of Lactobacillus GG or placebo suspended in vehicle and applied to the oropharynx and stomach every 12 hours. When clinically diagnosed with VAP using ACCP criteria, quantitative cultures using non-bronchoscopic bronchoalveolar lavage were collected to microbiologically confirm infection.
Key baseline characteristics were not different between the two groups. Compared to placebo (n=70), Lactobacillus (n=68) administration was associated with significantly lower rates of clinically-diagnosed VAP (25.0% vs. 47.1%, p=0.03) and microbiologically-confirmed VAP (19.1% vs. 40.0%, p=0.03). There was no significant difference in mortality (12% vs. 17%, p=0.47). Patients given Lactobacillus had significantly less ICU-associated diarrhea (3.1 days vs. 6.2 days, p=0.001), and Clostridium difficile disease (6% vs. 19%, p=0.02). Trends were seen towards reduced rates of bacteremia (38% vs. 73%, p=0.08) and urinary tract infections (21% vs. 33%, p=0.14) with Lactobacillus administration. Although total antibiotic consumption was not different between the two study arms (13.3 days vs. 16.3 days, p=0.16), patients given Lactobacillus had less antibiotics prescribed for pneumonia (8.6 days vs. 5.6 days, p=0.05) or Clostridium difficile (2.1 days vs. 0.5 days, p=0.02). No adverse events attributable to Lactobacillus administration were encountered.
Administration of the probiotic agent Lactobacillus GG to critically ill patients is safe and reduces the frequency of clinically-diagnosed and microbiologically-confirmed VAP. This probiotic agent also holds promise for the prevention of other nosocomial infections.
Probiotic therapy may provide a novel, inexpensive, non-antibiotic opportunity for the prevention of VAP.
Lee Morrow, No Financial Disclosure Information; No Product/Research Disclosure Information