Newly identified nutrients help the intestines to recover from previous infections and kill invasive bacteria

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

Scientists know that microbiota – the trillions of beneficial microbes that live harmoniously in our gut – can protect humans 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 microbiota and become less effective as bacteria develop resistance to medicines.

The scientists noted that microbiota that had been pre-infected and transmitted to germ-free mice could have prevented infection. Kpn. They identified a class of bacteria –Delta Proteobacteria– involved in combating these infections, and further analysis led them to identify taurine as the trigger Delta Proteobacteria activity.

Taurine helps the body to digest fats and oils and is found naturally in bile acids in the gut. The toxic hydrogen sulfide is a by-product of taurine. The scientists believe that low levels of taurine pathogens enable the colon to colonize, 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 contain bile acids containing taurine – can develop long-term infection protection.

The study found that taurine given to mice as a supplement in drinking water also prepares the microbiota to prevent infection. However, when mice drank water containing bismuth subsalicylate – a common remedy used without a prescription to treat diarrhea and gastritis – the protection of infections decreased because the production of hydrogen sulfide inhibited the bismuth.

Scientists from 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 Institute for Human Genome Research.