Newly identified nutrient helps the gut remember past infections and kill invading bacteria

Scientists studying the body’s natural defenses against bacterial infections have identified a nutrient – taurine – that helps the gut call up previous infections and kill invading bacteria, such as Klebsiella pneumoniae (Kpn). The finding, published in the journal Cell by scientists from five National Institutes of Health, could help search for alternatives to antibiotics.

Scientists know that 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 with a view to finding or improving natural treatments to replace antibiotics, which harm the microbiota and become less effective as bacteria develop resistance to drugs.

The scientists noted that microbiota that had previously been infected and transferred to germ-free mice were infected with Kpn. They identified a class of bacteria …Delta Proteobacteria– involved in fighting these infections, and after further analysis they discovered taurine as the trigger for it Delta Proteobacteria efficacy.

Taurine helps the body digest fats and oils and is naturally found in bile acids in the intestines. The toxic gas hydrogen sulfide is a byproduct of taurine. The scientists believe that low levels of taurine enable pathogens to colonize the gut, but high levels produce enough hydrogen sulfide to prevent colonization. During the study, the researchers realized that a single mild infection is enough to prepare the microbiota to resist another infection, and that the liver and gallbladder – which synthesize and store bile acids with taurine – can develop long-lasting infection protection.

The study found that taurine given to mice as a supplement in drinking water also prepared the microbiota to prevent infection. However, when mice drank water containing bismuth subsalicylate – a widely available over-the-counter drug used to treat diarrhea and upset stomach – protection against infections decreased because bismuth inhibits hydrogen sulfide production.

Scientists from the NIH’s 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 Kidney Diseases; and the National Human Genome Research Institute.