Genetically Engineered Probiotics

Intestinal microbiota is a key component of both the metabolism and immunity. These can be helpful in healthcare, especially for the management of digestive diseases and food-borne illnesses. Through genetic engineering it is possible to fully express biologically active copies of such powerful molecules from food and commensal bacteria. Genetically engineered probiotics can be used to treat inflammatory bowel disorders such as Crohn's disease, ulcerative colitis, as well as other disorders that result from an overactive immune system. Genetically modified (GM) probiotics are also used as food additives to control the release of human growth factors by the modified bacteria to fight against injury and inflammation in the gut. For example the use of a plant sugar called xylan to stimulate the genetically modified human gut probiotic bacterium Bacteroides ovatus to produce specific proteins that can repair damaged cells and dampen down the immune system in the intestine that causes inflammation and disease. Studies have confirmed that administration of xylan with the genetically engineered probiotic bacteria resulted in a significant improvement of colitis, reduced weight loss, improved stool consistency, reduced rectal bleeding and accelerated healing of damaged colonic cells. GM probiotics posses potential in clinical applications like delivery of antigens for vaccines and thus are more readily accepted. This would provide a safer method of vaccination than the use of attenuated pathogens e.g. GM, Lactococcus lactis, produces IL-10 in the mouse intestine. The safety of such organisms that produce very powerful bioactive substances is of major concern as excess production of these substances in a healthy individual may be detrimental.