Salmonella bacteria have the ability to reproduce selectively in the tumor and inhibit its growth.
Salmonella is a Gram-negative bacteria, one of the most common forms of bacteria that cause food poisoning in the world, where there are more than two thousand strains of Salmonella, all pathogenic to humans.
Salmonella is derived from the name of Daniel Elmer Salmon, a veterinarian who discovered and isolated it in 1885. The bacteria are transmitted through contaminated food and drink. Salmonella acquires a bad reputation, and all workers in the food production and inspection sector are very careful for it not to be present in food or water.
But there are studies that use salmonella as a destructive agent for cancer cells, because they have the ability to selectively multiply the tumor and inhibit its growth.
Salmonella works to break the tumor that is not recognized by the immune system by inhibiting the action of the enzyme (Indoleamine 2,3-dioxygenase), which is a mediator of cancer cells to escape from the immune system.
A practical experiment conducted in 2015 found that incubation of salmonella with animal cells with colon cancer gradually reduced the enzyme, and tumor size was significantly lower than that of the control sample.
Salmonella bacteria tend to accumulate more than 1,000 times in the carcinoma of the colon, compared with other tissues such as the liver and spleen. This is due to bacteria in the blood vessels of the tumor and chemical attraction through the compounds produced by tumors.
Salmonella bacteria prefer to grow in a nutrient-rich tumor environment where competition is less, and to protect themselves from the immune system.
Salmonella toxin activates the apoptosis of cancer cells. It is important to note that the malfunction of the cancerous tissue increases the distance between the capillaries and thus impedes the arrival of conventional treatment to the depth of the cancer cells. Therefore, salmonella bacteria can be used as a vector for treatment to reach the depth of the cancerous tumor. Salmonella also stimulates the secretion of antibodies.
Scientists have also studied the use of Listeria bacteria in the treatment of liver cancer. According to the 2014 study, the injection of mice with Listeria bacteria led to increased secretion of cytokines such as INF by immune cells, To prevent the reproduction and proliferation of cancer cells in the liver.