April 23, 2013
Contact Killing Of Salmonella Typhimurium By Human Fecal Bacteria
Our gut is home to trillions of bacteria, numbering more than the cells in the rest of our body, and these bacteria help us to digest our food, absorb nutrients and strengthen our immune system. This complex bacterial ecosystem, called the gut microbiota, also helps to prevent bad bacteria from colonizing our bodies and making us ill.
As part of the symbiotic relationship between the gut microbiota and our bodies, the bacteria derive nutrition from our food and convert it into compounds that we can´t make ourselves. Some of these compounds are part of the arsenal that combats harmful bacteria. To date, these are the only identified defense mechanisms associated with gut bacteria.
The researchers collected fecal samples from several healthy human donors and used the experimental colon model facility of the Institute of Food Research to culture fecal bacteria together with Salmonella under conditions that mimicked those in the human colon. Gut bacteria effectively inactivated Salmonella in mixed cultures but only when cell contact between both populations was possible. Salmonella inactivation was not observed when a membrane was included into the system to prevent cell contact between populations.
To better understand the way Salmonella is inactivated by contact with fecal bacteria, a mathematical model was developed. This new model will now be useful for finding ways of applying this new finding to ongoing efforts to reduce Salmonella infection. More information on the model can be found on the Gut Health and Food Safety blog.
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