Center for Meat Safety and Quality, Food Safety Cluster, Department of Animal Sciences, Colorado State University, 1171 Campus Delivery, Fort Collins, CO 80523-1171, USA.
Can J Microbiol. 2010 Sep;56(9):761-70. doi: 10.1139/w10-060.
This study examined the presence of antibiotic-resistant commensal bacteria among cattle operations representing areas heavily affected by agriculture, city locations representing areas affected by urban activities and indirectly affected by agriculture, and a national park representing an area not affected by agriculture. A total of 288 soil, fecal floor, and water samples were collected from cattle operations, from the city of Fort Collins, and from Rocky Mountain National Park (RMNP) in Colorado. In addition, a total of 42 new and unused feed, unused bedding, compost, and manure samples were obtained from the cattle operations. Total, tetracycline-resistant, and ceftiofur-resistant bacterial populations were enumerated by both standard culture plating and real-time PCR methods. Only wastewater samples from the cattle operations demonstrated both higher tetracycline-resistant bacterial counts (enumerated by the culture plating method) and tetracycline resistance gene copies (quantified by real-time PCR) compared to water samples collected from non-farm environments. The ceftiofur resistance gene, blaCMY-2, was not detectable in any of the samples, while the tetracycline resistance genes examined in this study, tet(B), tet(C), tet(W), and tet(O), were detected in all types of tested samples, except soil samples from RMNP. Tetracycline resistance gene pools quantified from the tet(O) and tet(W) genes were bigger than those from the tet(B) and tet(C) genes in fecal and water samples. Although only limited resistance genes, instead of a full set, were selected for real-time PCR quantification in this study, our results point to the need for further studies to determine natural and urban impacts on antibiotic resistance.
本研究检测了在代表受农业严重影响地区的牛场、代表受城市活动间接影响的城市地区以及代表未受农业影响的国家公园的牛场中，共生耐药菌的存在情况。共采集了 288 个来自牛场、科罗拉多州柯林斯堡市和落基山国家公园（RMNP）的土壤、粪便和水样，以及 42 个来自牛场的新的和未使用的饲料、未使用的垫料、堆肥和粪肥样本。通过标准培养平板和实时 PCR 方法对总、四环素耐药和头孢噻呋耐药细菌进行计数。只有牛场的废水样显示出更高的四环素耐药菌计数（通过培养平板法计数）和四环素耐药基因拷贝数（通过实时 PCR 定量），而来自非农场环境的水样则没有。在所有测试的样本中，均未检测到头孢噻呋耐药基因 blaCMY-2，而本研究检测的四环素耐药基因 tet(B)、tet(C)、tet(W)和 tet(O)，除了 RMNP 的土壤样本外，在所有类型的样本中均有检测到。从 tet(O)和 tet(W)基因定量的四环素耐药基因库大于从 tet(B)和 tet(C)基因定量的四环素耐药基因库。尽管在本研究中仅选择了有限的耐药基因而不是完整的基因集进行实时 PCR 定量，但我们的结果表明需要进一步研究以确定自然和城市因素对抗生素耐药性的影响。
