BACTERIAL ANTIBIOTIC RESISTANCE IN AGRICULTURE

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。细菌抗生素耐药性的出现是一个严重的公共卫生问题，因为它危及传染病的治疗。为了绕过这个问题，我们必须了解抗生素耐药性的程度。我们在四环素类抗生素广泛使用的奶牛场土壤中发现了多重耐药细菌。中心假设是奶牛场土壤中含有多重耐药细菌，或者已知的调节剂会导致多重耐药。这一假设的基本原理是，一旦知道农业中固有的和可诱导的细菌多药耐药性是多么普遍，就有可能采取措施来减少抗生素疗效有限的问题。为了研究这一点(1)，我们从新墨西哥州罗斯福县的当地奶牛场分离和鉴定了肠道细菌，并测定了与MAR相关的抗生素，如氯霉素、奈利地克酸、青霉素G和四环素的耐药性。我们纯化了质粒DNA，并鉴定了MAR的表型活性。其最小抑菌浓度(MIC)分别为氯霉素6~5 0g/m L、那利昔酸2~8g/m L、青霉素G 2 5~30 0g/m L、四环素1~80 g/m L。许多菌株对相同抗生素的最低抑菌浓度(MIC)有显著提高。从随机选择的菌株中提取的质粒DNA对氯霉素和青霉素G产生抗性。结论：奶牛场表层土壤中的肠道细菌具有多重耐药特性，含有耐药质粒。我们认为乳制品表土对土传人畜共患病很重要，因此暗示这种环境是细菌对临床相关抗生素耐药性的储存库。1.Burgos，J.M.，B.A.Ellington和M.F.Varela。2005年。奶牛场表层土壤中多重耐药肠道细菌的存在《乳品科学》。88：1391-1398。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The emergence of bacterial antibiotic resistance is a serious public health concern as it compromises treatment of infectious disease. To circumvent this problem, we have to understand the extent of antibiotic resistance. We have found multi-drug resistant bacteria in dairy farm soil, where tetracycline antibiotics are widely used. The central hypothesis is that dairy farm soil harbors multidrug resistant bacteria or that known modulators induce multidrug resistance. The rationale for the hypothesis is that once it is known how widespread intrinsic and inducible bacterial multidrug resistances are in agriculture, it will be possible to invoke measures to reduce the problem of the limited efficacy of antibiotics. To study this (1), we isolated and identified enteric soil bacteria from local dairy farms within Roosevelt County, NM, determined the resistance profiles to antibiotics associated with mar, such as chloramphenicol, nalidixic acid, penicillin G and tetracycline. We purified plasmid DNA and characterized mar phenotypic activity. The minimal inhibitory concentrations (MICs) of antibiotics for the isolates ranged between 6 - 50 ?g/mL for chloramphenicol, 2-8 ?g/mL for nalidixic acid, 25- 300 ?g/mL for penicillin G and 1- 80 ?g/mL for tetracycline. Many of the isolates had significantly enhanced MICs for the same antibiotics in the presence of salycilate. Plasmid DNA extracted from randomly chosen isolates conferred resistances to chloramphenicol and penicillin G. We conclude that enteric bacteria from dairy farm topsoil are multi-drug resistant and harbor antibiotic resistance plasmids. We suggest dairy topsoil is important for soil-borne zoonosis, thus implicating this environment as a reservoir for bacterial resistance against clinically relevant antibiotics. 1. Burgos, J. M., B. A. Ellington, and M. F. Varela. 2005. Presence of Multidrug-Resistant Enteric Bacteria in Dairy Farm Topsoil. J. Dairy Sci. 88:1391-1398.