Newly identified nutrient helps gut remember previous infections and kill invasive bacteria

Scientists studying the body’s natural defenses against bacterial infections have identified a nutrient – taurine – that helps the intestine to remember previous infections and kill invasive bacteria, such as Klebsiella pneumoniae (Kpn) The discovery, published in the newspaper Cell by scientists from five institutes at the National Institutes of Health, it could assist in efforts to find alternatives to antibiotics.

Scientists know that the microbiota – the trillions of beneficial microbes that live harmoniously in our gut – can protect people from bacterial infections, but little is known about how they provide protection. Scientists are studying the microbiota to find or improve natural treatments to replace antibiotics, which damage the microbiota and become less effective as bacteria develop resistance to drugs.

Scientists noted that the microbiota that experienced a previous infection and transferred to germ-free mice helped prevent infection Kpn. They identified a class of bacteria –Deltaproteobacteria– became involved in combating these infections, and further analysis led them to identify taurine as the trigger for Deltaproteobacteria activity.

Taurine helps the body digest fats and oils and is found naturally in bile acids in the intestine. The poisonous hydrogen sulfide gas is a by-product of taurine. Scientists believe that low levels of taurine allow pathogens to colonize the intestine, but high levels produce enough hydrogen sulfide to prevent colonization. During the study, the researchers realized that a single mild infection is sufficient to prepare the microbiota to resist subsequent infection, and that the liver and gallbladder – which synthesize and store bile acids containing taurine – can develop protection against infections from long term.

The study found that taurine given to rats as a supplement in drinking water also prepared the microbiota to prevent infection. However, when the rats drank water containing bismuth subsalicylate – a common medication used to treat diarrhea and stomach pains – protection against infections declined because bismuth inhibits the production of hydrogen sulfide.

Scientists from the NIH National Institute of Allergy and Infectious Diseases led the project in collaboration with researchers from the National Institute of General Medical Sciences; the National Cancer Institute; the National Institute of Diabetes and Digestive and Renal Diseases; and the National Human Genome Research Institute.