Bioactive Molecules Produced by Probiotics to Control Enteric Pathogens

프로바이오틱스가 생산하는 생리활성 물질의 장내 유해균 억제 효과

There is a burgeoning number of products on the market that contain probiotics, but do they do you any good? What exactly are probiotics? They have been defined as living organisms that, when ingested in sufficient quantities, provide health benefits beyond basic nutrition. They are often referred to as "friendly bacteria" or "good bacteria." Probiotics have been claimed, amongst other things, to (i) reduce the incidence of colon cancer and other diseases of the colon, such as IBS, (ii) stimulate the immune system, (iii) have anti-hypertensive and anti-cholesterolemic properties, (iv) mitigate against the effect of antibiotics on the intestinal microbiota, and (v) protect against gastrointestinal infections. However, the scientific basis for many of these claims is not well-established. Indeed, the European Food Safety Authority has denied the use of several health claims associated with probiotics, particularly those related to mitigation of diarrhea following consumption of antibiotics. Thus, there is a need for research on the mechanisms of action of probiotics. We have been mainly interested in the use of probiotics to control enteric infections. There are several possible modes of action to explain how probiotics may protect the host from enteric pathogens, including competitive exclusion and immunomodulation. We have shown that probiotics produce bioactive molecules that interfere with bacterial cell-cell communication (also called quorum sensing), and this results in a down-regulation of virulence genes that are responsible for attachment of the pathogen to the gastrointestinal epithelium. These bioactive molecules act on a variety of bacteria, including enterohemorrhagic and enterotoxigenic Escherichia coli, Salmonella, Clostridium difficile and Clostridium perfringens, and there is evidence that they can inhibit the formation of biofilms by Listeria monocytogenes. These bioactive molecules, which are peptidic in nature, can exert their effects not only in vitro but also in vivo, and we have shown that they mitigate against E. coli O157:H7 and Salmonella in mice and Salmonella and E. coli K88 infections in pigs. They can be delivered in foods such as yoghurt and maintain their activity.

시장에는 프로바이오틱스를 포함한 무수히 많은 제품이 판매되고 있는데, 우리에게 어떤 이로운 점을 줄 수 있는지 궁금해 한 적이 있었을 것이다. 프로바이오틱스는 기본적인 영양 측면을 배제하고, 우리가 유효한 양을 섭취하였을 때 건강상의 이점을 주는 살아있는 미생물로 정의된다. 프로바이오틱스는 유용하고 건강에 좋은 미생물로도 불려지고 있으며, 다음과 같은 다섯 가지 측면에서 건강 기능성이 있는 것으로 강조되어 왔는데, 1) 대장암 및 IBS와 같은 다른 대장(결장)관련 질병의 발병율 감소, 2) 면역 시스템의 촉진, 3) 항고혈압 및 항콜레스테롤 작용, 4) 장내세균에 작용하는 항생제의 효과를 경감시키고, 5) 위장관 감염을 예방시키는 점이다. 그러나 이러한 건강기능 작용들에 대한 과학적인 근거가 충분히 구축되어 있지는 않아, 유럽식품 위생위원회(Euroupe Food Safety Authority)는 항생제 투여에 따른 설사증상의 완화와 같은 건강기능 표시를 금지하고 있어, 프로바이오틱스의 작용기전에 대한 연구가 필요한 시점이라 하겠다.