Evidence in the eye of the beholder: about probiotics and VAP prevention

Excerpt

Ventilator-associated pneumonia (VAP) remains an important source of morbidity and therefore avoiding this complication continues to be a priority in terms of patient safety and quality improvement [1]. A variety of VAP prevention measures are available and include strategies targeting bacterial translocation, biofilm formation, micro-aspiration of subglottic secretions, reduction of exposure time, and modulation of colonization [2‐4]. Regarding the last of these, in the past decades, the use of probiotics has come to the front. Probiotics are generally defined as living organisms that—when ingested in adequate amounts—provide health benefits to the host [5]. In the past two decades, probiotics have increasingly been considered as an effective and safe approach to improve gastrointestinal barrier function, modification of the gut flora (i.e., avoiding colonization with potential pathogenic microorganisms, PPMOs), and immunomodulation [6]. Although results appear to be variable according to the index population, various benefits have been described for either critically and non-critically ill patients, including prevention of Clostridium difficile-associated diarrhea, prevention of infectious complications in patients with severe acute pancreatitis, post liver transplantation, and following major abdominal surgery. Also, step by step, the evidence is accumulating for the use of probiotics in the prevention of VAP. In a recent article in Intensive Care Medicine, Zeng et al. report on an open-label randomized multicenter study to assess the efficacy of the administration of a probiotic capsule containing active Bacillus subtilis and Enterococcus faecalis to prevent VAP [7]. The intervention group received the capsule thrice daily for 2 weeks in addition to standard precautions for VAP prevention. The control group received standard measures to prevent VAP. Two hundred and fifty patients were randomized and 235 completed the study, of which 118 were in the intervention arm. In brief, a significant reduction in microbiologically confirmed VAP was demonstrated (36.4 vs. 50.4 %; p = 0.031), but not in clinically suspected VAP (40.7 vs. 53.0 %; p = 0.059). The latter is probably the reason why probiotics neither resulted in a reduction of antimicrobial consumption nor in a shortening of ICU and hospital stay. Acquisition of PPMOs in the stomach was lower in the intervention group (24 vs. 44 %; p = 0.004), but no difference was observed in acquisition of PPMOs in the oropharynx, and no differences were noted in rates of eradication of PPMOs in either the oropharynx or the stomach. …