Antibiotics save millions of lives. But their tendency to kill helpful and harmful bacteria alike, coupled with the growing problem of antibiotic resistance, means that they are not without their downside. Probiotics consisting of beneficial microorganisms, meanwhile, have the potential to deliver the benefits of antibiotics minus the pitfalls. Yet, until now, evidence of their efficacy has been largely anecdotal, their mechanisms of action poorly understood. Thanks to a pair of papers recently published in Science (September 23, 2016) and in Science Immunology (September 22, 2016) by researchers at The Rockefeller University, however, that is beginning to change. The studies demonstrate that an enzyme produced by a common intestinal microbe can protect the guts of worms and mammals alike from attack by harmful bacteria, and offer important insights into how it does so. Together, the findings could lead to the development of probiotics for use against such dangerous pathogens as Clostridium difficile, a leading cause of hospital-acquired infections. The Rockefeller researchers set out to investigate the probiotic potential of the microbe Enterococcus faecium in the roundworm Caenorhabditis elegans. Although E. faecium has long been used as a probiotic in livestock, its mode of action has never been clear. And it is far from being an ideal probiotic for use in humans: according to Kavita Rangan, Ph.D., first author of the Science paper (“A Secreted Bacterial Peptidoglycan Hydrolase Enhances Tolerance to Enteric Pathogens” and a member of Howard Hang’s Laboratory of Chemical Biology and Microbial Pathogenesis at The Rockefeller. E. faecium readily acquires antibiotic resistance in hospital settings and can lead to dangerous infections in people with compromised immune systems.Login Or Register To Read Full Story