Probiotics take a knock in the gut?

Probiotic therapies involve the use of living microorganisms to treat or prevent disease.  A number of creative applications are being developed for treatment of colitis, prevention of dental caries, and control of infectious disease.  Some of these applications are likely to involve genetically modified strains of bacteria. Look for more of these in the next decade.

Yet as with gene transfer, active (that is, living) pharmaceuticals might pack surprises.  A news item from the Feb 1, 2008 issue of Science provides one possible example.  In a placebo-controlled trial testing a cocktail of different bacteria for the prevention of infection in patients with acute pancreatitis, death rates were significantly elevated in the probiotic group.  One explanation, of course, is that the results are a statistical fluke.  A less comforting possibility, however, is that the bacteria mixture prompted an unexpected immune reaction. Stay tuned as scientists and investigators scope out what happened.  (photo credit: Rowett Research Institute scanning electron microscope image of Lactobacillus bacteria)