Wepking Carl, Avera Bethany, Badgley Brian, Barrett John E, Franklin Josh, Knowlton Katharine F, Ray Partha P, Smitherman Crystal, Strickland Michael S
Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
Department of Ecosystem Science and Sustainability, Colorado State University, Fort Collins, CO 80521, USA.
Proc Biol Sci. 2017 Mar 29;284(1851). doi: 10.1098/rspb.2016.2233.
Intensifying livestock production to meet the demands of a growing global population coincides with increases in both the administration of veterinary antibiotics and manure inputs to soils. These trends have the potential to increase antibiotic resistance in soil microbial communities. The effect of maintaining increased antibiotic resistance on soil microbial communities and the ecosystem processes they regulate is unknown. We compare soil microbial communities from paired reference and dairy manure-exposed sites across the USA. Given that manure exposure has been shown to elicit increased antibiotic resistance in soil microbial communities, we expect that manure-exposed sites will exhibit (i) compositionally different soil microbial communities, with shifts toward taxa known to exhibit resistance; (ii) greater abundance of antibiotic resistance genes; and (iii) corresponding maintenance of antibiotic resistance would lead to decreased microbial efficiency. We found that bacterial and fungal communities differed between reference and manure-exposed sites. Additionally, the β-lactam resistance gene was 5.2-fold greater under manure exposure, potentially due to the use of cephalosporin antibiotics in dairy herds. Finally, abundance was positively correlated with indicators of microbial stress, and microbial mass-specific respiration, which increased 2.1-fold under manure exposure. These findings demonstrate that the maintenance of antibiotic resistance associated with manure inputs alters soil microbial communities and ecosystem function.
强化牲畜养殖以满足全球人口增长的需求，与此同时兽医抗生素的使用量和土壤中粪便投入量都在增加。这些趋势有可能增加土壤微生物群落中的抗生素抗性。抗生素抗性持续增加对土壤微生物群落及其调控的生态系统过程的影响尚不清楚。我们比较了美国成对的对照地点和受奶牛粪便影响地点的土壤微生物群落。鉴于已表明粪便暴露会导致土壤微生物群落中的抗生素抗性增加，我们预计受粪便影响的地点将表现出：（i）土壤微生物群落组成不同，向已知具有抗性的分类群转变；（ii）抗生素抗性基因丰度更高；（iii）相应地，抗生素抗性的维持会导致微生物效率降低。我们发现对照地点和受粪便影响地点的细菌和真菌群落存在差异。此外，在粪便暴露下β-内酰胺抗性基因丰度高5.2倍，这可能是由于奶牛群中使用了头孢菌素抗生素。最后，[此处原文可能缺失某个指标]丰度与微生物应激指标呈正相关，且微生物质量特定呼吸在粪便暴露下增加了2.1倍。这些发现表明，与粪便投入相关的抗生素抗性维持会改变土壤微生物群落和生态系统功能。
