Researchers from UC Davis have discovered how the bacteria Salmonella enterica - a common cause of food poisoning - fosters its own growth inside the human intestine.
Salmonella is frequently in the news as a source of food poisoning outbreaks, usually from eating poorly cooked or unhygienically prepared eggs or meat. Salmonella infection, known as salmonellosis, causes diarrhea, fever, vomiting and abdominal cramps. Although most people recover after several days, it may be fatal, especially in the elderly, infants, and people with an impaired immune system.
"We have discovered Salmonella's cunning trick that allows it to quickly take over and outgrow the beneficial microbes in our intestine," Nature quoted Andreas Bdumler as saying.
When people ingest Salmonella, it invades the surface of the intestine. Our immune system responds by producing oxygen radicals to kill the bacteria. Although some Salmonella bacteria are killed by this response, many more benefit: the oxygen radicals create a sulfur compound called tetrathionate, which Salmonella are able to use instead of oxygen for respiration - which helps it live and reproduce.
"This gives Salmonella a tremendous advantage over the gut bacteria that must grow by fermentation," said Sebastian E. Winter.
Additionally, it stimulates an inflammatory response in the intestine, causing the severe diarrhea and vomiting that is the body's attempt to rid itself of the pathogenic bacteria, at the same time enabling Salmonella's spread.
Finding that tetrathionate is important in human Salmonella infection opens up new avenues for research in finding an effective treatment for salmonellosis.
"We are hopeful that by targeting sulfur compounds we can stop the bacteria from establishing a foothold in the intestine," said Baumler.
The findings are published in the Sept. 23 issue of the journal Nature.