Prebiotics, probiotics, synbiotics in surgery-are they only trendy, truly effective or even dangerous?

Despite advances in surgical technique and intensive care medicine, nosocomial bacterial infections frequently occur in patients after major abdominal surgery and have a negative impact on operative outcome and hospital costs. In parallel, the routine use of antibiotics led to the development of resistance. Some probiotics (living bacteria) and prebiotics (fibers) are able to stabilize the intestinal barrier and prevent bacterial translocation and infections. The aim of this article was to review all available experience with pro- and prebiotics in surgical trials. Medical databases were searched for animal trials and randomized controlled studies with pro- and prebiotics in surgical patients. Primary endpoint of all reported studies was the occurrence of bacterial infections. In addition, type and concentration of the pro- and prebiotics, duration of therapy, adverse events, and other effects were investigated. In three animal trials and in ten of the 15 clinical studies, probiotics or synbiotics led to a significant reduction of bacterial infection rates compared to the control groups. In two studies, there was a positive trend in the groups with synbiotics, but the results were not statistically significant. Two studies showed no effect, and in one study, the mortality rate was even higher in the synbiotic group. Except in the latter study, no severe adverse events were observed. The success of treatment depends on the synbiotic preparation and the length of therapy. Patients after surgery of the liver and pancreas and multiple trauma patients profited most from synbiotic treatment. The existing randomized controlled trials demonstrated a positive effect of synbiotics in patients with high-risk operations; however, synbiotic preparations should be extensively tested before using them in clinical trials.