ACID TOLERANCE/MICROBIAL ECOLOGY--E COLI 0157:H7 IN RUME

耐酸性/微生物生态学--酸模中的大肠杆菌 0157:H7

• 批准号: 6316653
• 负责人: TAMMY MAY
• 金额: $ 6.87万
• 依托单位: NEW MEXICO STATE UNIVERSITY LAS CRUCES
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2001-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6316653
• 关键词: Escherichia coli 0157:H7; acidity /alkalinity; anaerobic bacteria; biotherapeutic agent; cow; disease reservoirs; environmental adaptation; feces analysis; high performance liquid chromatography; host organism interaction; microorganism growth; molecular cloning; nucleic acid probes; nucleic acid quantitation /detection; pulsed field gel electrophoresis

E. coli O157:H7 is an important pathogen derived from animal products or vegetables treated with animal waste. One of the factors that enables this organism to survive the stomach and colonize the large intestine of humans is its ability to tolerate acidic conditions. The mechanisms that confer acid tolerance are unclear, but probably colonization inhibition could be developed. Our overall goal for this proposal is to understand the role of acid 1) optimization of procedures for extracting E. coli O157:H7 DNA from bovine ruminal fluid and feces, 2) a 'shock' is necessary to induce the tolerance, 3) determination of the possible roles for rpoS (and other acid resistance systems) and anaerobiosis in allowing E. coli 0157:H7 to compete with microorganisms from the O157:H7 and ruminal lactate-utilizing bacteria as well as ruminal lactate-producing bacteria as well as ruminal lactate-producing bacteria. Our working hypothesis is that organisms that utilize lactate can assist in decreasing carriage of E. coli 0157:H7. It has been suggested that low ruminal pH of cattle consuming corn-based diets induces acid tolerance in E. coli O157:H7. However, this organism is capable of surviving in manure for long periods of time under environmental conditions. Thus, acid resistance may already be induced. The most promising plan of action appears to be reduction of E. coli O157:H7 carriage in cattle. Development of probiotic organisms that are indigenous to the rumen ecosystem holds the greatest potential for success. Thus, the long-term objective for our research is to develop probiotic treatment based on organisms indigenous to the rumen environment. The outcome of this study will assist others in future applications of this organism in management of infection by cattle, and hopefully in the protection of the food supply. By employing a host of techniques including anaerobic microbiology, PCR amplification, and hybridization, we are confident that we can realize the aims in this proposal within four years.

E.大肠杆菌O 157：H7是一种重要的病原菌，来源于动物产品或经动物粪便处理的蔬菜。使这种微生物能够在胃中存活并在人类大肠中定植的因素之一是它能够耐受酸性条件。赋予酸耐受性的机制尚不清楚，但可能是殖民抑制可以开发。我们这个提案的总体目标是了解酸的作用1）优化提取E的程序。coliO 157：H7 DNA的耐药性; 2）“休克”是诱导耐受的必要条件; coli 0157：H7与来自O 157：H7的微生物和瘤胃乳酸利用细菌以及瘤胃乳酸产生细菌和瘤胃乳酸产生细菌竞争。我们的工作假设是，利用乳酸的生物体可以帮助减少大肠杆菌的携带。coli0157：H7。研究表明，低瘤胃pH值的牛消耗玉米为基础的饮食诱导酸性耐受性E。coli O157：H7。然而，这种生物能够在环境条件下长时间在粪肥中存活。因此，抗酸性可能已经被诱导。最有希望的行动计划似乎是减少E。大肠杆菌O 157：H7在牛中的携带情况。瘤胃生态系统固有的益生菌生物的开发具有最大的成功潜力。因此，我们研究的长期目标是开发基于瘤胃环境固有生物的益生菌治疗。这项研究的结果将有助于其他人在未来的应用程序中，这种生物体的牛感染的管理，并希望在保护食品供应。通过采用厌氧微生物学、PCR扩增和杂交等一系列技术，我们有信心在四年内实现这一提案的目标。