London: Boosting levels of bacteria in your gut could be a new form of treatment against food poisoning, a new study has found. Researchers say that the byproduct of a group of bacteria found in the intestines hinders Salmonella from growing and multiplying.
The byproduct, known as propionate, does not activate the immune system’s response to the infection but rather slows down the time it takes to grow and spread. The team, from Stanford University in California, says that not only does its study show why people may respond to infection differently, but also could provide a new form of treatment for this form of food poisoning.
Salmonella infections occur after eating raw meat and eggs or foods that are contaminated with the bacteria. Symptoms can include nausea, vomiting, diarrhea, and abdominal pain that generally last between four and seven days.
According to the Centers for Disease Control and Prevention (CDC), Salmonella is the cause of 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths in the US annually. Most people can recover without treatment, although there are cases where antibiotics or IV fluids are needed.
Scientists have been studying various strains of mice to determine which genes make them more susceptible to infections like Salmonella. Lead author Amanda Jacobson, a graduate student in microbiology and immunology at Stanford University, said that after two strains of the mice were injected with the pathogen, they had different levels of it in their stomachs.
She said the researchers then set out to find if differences in the gut bacteria of the mice were affecting these different levels of infection. For the study, the team first performed fecal transplants in the mice, a process by which the rodents are administered antibiotics that kill their normal gut bacteria and then receive the excrement of other mice.
Some of the feces came from mice that are resistant to Salmonella infection and some came from mice that were more susceptible to it. From this, the researchers found that groups of bacteria were different between the two strains of mice and that their typical makeup in the intestines dictated differences in the growth of Salmonella.
They determined that a group of bacteria, called Bacteroides, were more present in the rodents who received the fecal transplant from mice that were protected from infection. Many short-chain fatty acids are produced by Bacteroids, one of them being propionate – which was three times greater in the mice that were resistant to Salmonella.
However, what the researchers learned was that propionate does not trigger an immune response to the pathogen. Instead, it reduces the internal acidity of the Salmonella cells, requiring more time for the bacteria to grow.
‘Collectively, our results show that when concentrations of propionate, which is produced by Bacteroides, in the gut are high, Salmonella is unable to raise their internal pH to facilitate cellular functions required for growth,’ Jacobson said.
‘Of course, we would want to know how translatable this is to humans.’ The researchers say they hope their findings could offer alternative forms of treatment. They say some antibiotics used to treat Salmonella also kill helpful bacteria, but using propionate could prevent such a situation from occurring.
What is Food Poisoning?
Food poisoning is an illness caused by eating food contaminated with bacteria, such as salmonella or E.coli, or a virus, like a norovirus. Raw meat and shellfish, unpasteurized milk, and ‘ready-to-eat foods, like soft cheeses, are most likely to be contaminated.