Abstract
This article is based on a review of published literature, mainly from 2005 to 2008. Several reports demonstrate statistically significant beneficial health effects of probiotic supplementation, especially for the treatment of rotavirus-associated diarrhoea. The following main topics have been reviewed: bacterial translocation from the gut and infectious disease; virulence factors including toxicity; metabolic functions including host storage, platelet aggregation, deconjugation of bile acids, and degradation of mucin. Furthermore, resistance to antimicrobials, with emphasis on the location of the genes involved, has been reviewed. Studies concerning probiotic supplementation in hospital patients suffering from acute pancreatitis, antibiotic-associated diarrhoea, including Clostridium difficile infection, and non-alcoholic fatty liver disease are reviewed. Supplementation with probiotic bacteria in critically ill children, e.g. in intensive care, is also discussed. The use of probiotics for patients with diarrhoea, Helicobacter pylori infection and inflammatory bowel disease is mentioned, as well as for patients with AIDS, urogenital infections, and small intestinal bacterial overgrowth. Particular attention has been paid to a large Dutch study (PROPATRIA), which showed increased mortality in patients with acute pancreatitis who were given enteral nutrition to which probiotics had been added, compared with enteral nutrition alone. Similarities in some acquired resistance genes between probiotic microorganisms and other bacteria of human origin suggest the transfer of resistance genes between commensal microorganisms in the complex gastrointestinal tract ecosystem. Intake of probiotic microorganisms that carry transferable antimicrobial resistance genes may increase the risk of the transfer of such genes to the resident microbiota in patients. Although some beneficial effects have been reported in some patient groups, we conclude that the adverse effects that have been observed are well documented, thus indicating that caution should be observed in administering probiotic bacteria to critically ill patients.
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Acknowledgements
We would like to thank the Norwegian Scientific Committee for Food Safety where this risk assessment was performed.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.