Carbohydrate utilization by enterohaemorrhagic Escherichia coli O157:H7 in bovine intestinal content.
Carbohydrate utilization by enterohaemorrhagic Escherichia coli O157:H7 in bovine intestinal content.
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DOI：
10.1111/1462-2920.12019
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发表时间：
2013-02
影响因子：
5.1
通讯作者：
Martin C
中科院分区：
文献类型：
--
作者：
Bertin Y;Chaucheyras-Durand F;Robbe-Masselot C;Durand A;de la Foye A;Harel J;Cohen PS;Conway T;Forano E;Martin C
牛胃肠道是引起食源性感染的肠出血性大肠杆菌（EHEC）的主要宿主。表征肠出血性大肠杆菌在牛肠内优先使用的营养物质将有助于制定减少肠出血性大肠杆菌携带的生态策略。然而，支持肠出血性大肠杆菌在牛肠内生长的碳源文献很少。在本研究中，从屠宰场采集的健康奶牛小肠内容物（BSIC）中检测到极低浓度的葡萄糖（牛日粮多糖中含量最多的单体）。据报道，覆盖肠细胞的黏液层中含有6种碳水化合物[半乳糖、n -乙酰氨基葡萄糖（GlcNAc）、n -乙酰半乳糖胺（GalNAc）、焦糖、甘露糖和n -乙酰神经氨酸（Neu5Ac）]，在BSIC中首次被量化，碳水化合物的总浓度为4.2 mM。EHEC菌株O157:H7 EDL933在BSIC中呈指数增长的过程中，酶降解六种黏液衍生碳水化合物所需的基因高度表达，并且在EHEC中比在牛共生大肠杆菌中更强烈地被诱导。此外，EDL933消耗BSIC中存在的游离单糖的速度比驻地微生物群和共生大肠杆菌更快，这表明肠出血性大肠杆菌在牛肠道中具有分解代谢黏液源碳水化合物的竞争能力。这些糖的分解代谢所需的EDL933基因突变已经被构建，并且突变体与野生型菌株的生长竞争清楚地表明，甘露糖、GlcNAc、Neu5Ac和半乳糖分解代谢赋予BSIC中的肠出血性大肠杆菌高度竞争的生长优势，并且可能代表了牛小肠中肠出血性大肠杆菌菌株的生态位。EDL933利用这些黏液来源的单糖显然是BSIC中肠出血性大肠杆菌快速生长和保持与共生大肠杆菌竞争生长速度所必需的。结果提示了O157:H7大肠杆菌在牛肠中的生存策略，即肠出血性大肠杆菌迅速消耗黏液衍生的碳水化合物，这些碳水化合物被属于肠道微生物群的细菌（包括共生大肠杆菌）消耗得很少。
The bovine gastrointestinal (GI) tract is the main reservoir for enterohaemorrhagic Escherichia coli (EHEC) responsible for food-borne infections. Characterization of nutrients preferentially used by EHEC in the bovine intestine would help to develop ecological strategies to reduce EHEC carriage. However, the carbon sources that support the growth of EHEC in the bovine intestine are poorly documented. In this study, a very low concentration of glucose, the most abundant monomer included in the cattle dietary polysaccharides, was detected in bovine small intestine contents (BSIC) collected from healthy cows at the slaughterhouse. Six carbohydrates reported to be included in the mucus layer covering the enterocytes [galactose, N-acetyl-glucosamine (GlcNAc), N-acetylgalactosamine (GalNAc), fucose, mannose and N-acetyl neuraminic acid (Neu5Ac)] have been quantified for the first time in BSIC and accounted for a total concentration of 4.2 mM carbohydrates. The genes required for enzymatic degradation of the six mucus-derived carbohydrates are highly expressed during the exponential growth of the EHEC strain O157:H7 EDL933 in BSIC and are more strongly induced in EHEC than in bovine commensal E. coli. In addition, EDL933 consumed the free monosaccharides present in the BSIC more rapidly than the resident microbiota and commensal E. coli, indicating a competitive ability of EHEC to catabolize mucus-derived carbohydrates in the bovine gut. Mutations of EDL933 genes required for the catabolism of each of these sugars have been constructed, and growth competitions of the mutants with the wild-type strain clearly demonstrated that mannose, GlcNAc, Neu5Ac and galactose catabolism confers a high competitive growth advantage to EHEC in BSIC and probably represents an ecological niche for EHEC strains in the bovine small intestine. The utilization of these mucus-derived monosaccharides by EDL933 is apparently required for rapid growth of EHEC in BSIC, and for maintaining a competitive growth rate as compared with that of commensal E. coli. The results suggest a strategy for O157:H7 E. coli survival in the bovine intestine, whereby EHEC rapidly consumes mucus-derived carbohydrates that are poorly consumed by bacteria belonging to the resident intestinal micro-biota, including commensal E. coli.
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影响因子：
5.1
作者：
Bertin, Yolande;Girardeau, J. P.;Martin, Christine
通讯作者：
Martin, Christine
影响因子：
5
作者：
Amaretti, Alberto;Tamburini, Elena;Rossi, Maddalena
通讯作者：
Rossi, Maddalena
影响因子：
3.5
作者：
BRYANT, MP;BURKEY, LA
通讯作者：
BURKEY, LA
DOI：
10.1073/pnas.120163297
发表时间：
2000-06-06
影响因子：
11.1
作者：
Datsenko, KA;Wanner, BL
通讯作者：
Wanner, BL
影响因子：
56.9
作者：
Diez-Gonzalez, F;Callaway, TR;Russell, JB
通讯作者：
Russell, JB