Bacterial diversity of Escherichia coli in the gut : a reason to re-evaluate probiotic formulations?

Humans and animals are increasingly being subjected to various probiotic formulations with the claim of providing a number of health benefits to the consumer. These formulations usually incorporate bacterial consortia comprising of mostly lactic acid bacteria (LAB). Recent studies have shown that strains found in different regions of the gut are genetically different from each other and may therefore have different abilities to interact with bacteria that they come into contact with. Even LAB show differences in their ability to interact, and further, inhibit growth of pathogenic bacteria in vitro due to individual strain differences. If these results are repeatedly shown to be true in future assessments, an evaluation of bacterial consortia used in probiotic formulations may now be necessary. This may have an impact in the way future probiotic formulations are prepared.