Microbiology, effects, and safety of probiotics

Probiotics are being used with some success in pediatrics. Lactobacilli, bifidobacteria, and, with some limitations, some other probiotic microorganisms are considered nontoxic and nonpathogenic. They contain no virulence factors, do not release putrefactive metabolites or tumor-promoting enzymes, and do not cause mucus decomposition. Lactobacilli that have been found during opportunistic infections in rare cases almost always originated from the indigenous intestinal flora. The best proof of their sanitary harmlessness is that they have, in part, been used for a long time already without evidence of health risk. A recent study from the Netherlands, however, found that a complex mixture of probiotic bacteria increased mortality in patients with severe acute pancreatitis. This shows that the use of insufficiently examined probiotic preparations can be a considerable risk in immunocompromised critically ill patients.