Shoaf Kari, Mulvey George L, Armstrong Glen D, Hutkins Robert W
Department of Food Science and Technology, University of Nebraska-Lincoln, 338 FIC, Lincoln, NE 68583-0919, USA.
Infect Immun. 2006 Dec;74(12):6920-8. doi: 10.1128/IAI.01030-06. Epub 2006 Sep 18.
Prebiotic oligosaccharides are thought to provide beneficial effects in the gastrointestinal tract of humans and animals by stimulating growth of selected members of the intestinal microflora. Another means by which prebiotic oligosaccharides may confer health benefits is via their antiadhesive activity. Specifically, these oligosaccharides may directly inhibit infections by enteric pathogens due to their ability to act as structural mimics of the pathogen binding sites that coat the surface of gastrointestinal epithelial cells. In this study, the ability of commercial prebiotics to inhibit attachment of microcolony-forming enteropathogenic Escherichia coli (EPEC) was investigated. The adherence of EPEC strain E2348/69 on HEp-2 and Caco-2 cells, in the presence of fructooligosaccharides, inulin, galactooligosaccharides (GOS), lactulose, and raffinose was determined by cultural enumeration and microscopy. Purified GOS exhibited the greatest adherence inhibition on both HEp-2 and Caco-2 cells, reducing the adherence of EPEC by 65 and 70%, respectively. In addition, the average number of bacteria per microcolony was significantly reduced from 14 to 4 when GOS was present. Adherence inhibition by GOS was dose dependent, reaching a maximum at 16 mg/ml. When GOS was added to adhered EPEC cells, no displacement was observed. The expression of BfpA, a bundle-forming-pilus protein involved in localized adherence, was not affected by GOS, indicating that adherence inhibition was not due to the absence of this adherence factor. In addition, GOS did not affect autoaggregation. These observations suggest that some prebiotic oligosaccharides may have antiadhesive activity and directly inhibit the adherence of pathogens to the host epithelial cell surface.
益生元低聚糖被认为通过刺激肠道微生物群特定成员的生长，对人和动物的胃肠道产生有益影响。益生元低聚糖可能带来健康益处的另一种方式是通过其抗黏附活性。具体而言，这些低聚糖可能直接抑制肠道病原体的感染，因为它们能够作为覆盖胃肠道上皮细胞表面的病原体结合位点的结构模拟物。在本研究中，研究了市售益生元抑制微菌落形成的肠致病性大肠杆菌（EPEC）黏附的能力。通过培养计数和显微镜检查，测定了在低聚果糖、菊粉、低聚半乳糖（GOS）、乳果糖和棉子糖存在的情况下，EPEC菌株E2348/69对HEp-2和Caco-2细胞的黏附情况。纯化的GOS对HEp-2和Caco-2细胞均表现出最大的黏附抑制作用，分别使EPEC的黏附减少了65%和70%。此外，当存在GOS时，每个微菌落的细菌平均数量从14显著减少到4。GOS的黏附抑制作用呈剂量依赖性，在16 mg/ml时达到最大值。当将GOS添加到已黏附的EPEC细胞中时，未观察到置换现象。参与局部黏附的束状菌毛蛋白BfpA的表达不受GOS影响，表明黏附抑制不是由于缺乏这种黏附因子。此外，GOS不影响自聚集。这些观察结果表明，一些益生元低聚糖可能具有抗黏附活性，并直接抑制病原体对宿主上皮细胞表面的黏附。
