Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008, United States.
Department of Geography, Western Michigan University, Kalamazoo, MI 49008, United States.
Sci Total Environ. 2018 Jun 15;627:1234-1241. doi: 10.1016/j.scitotenv.2018.01.343. Epub 2018 Feb 7.
The widespread use of antibiotics in human and veterinary medicine to treat pathogenic bacteria has resulted in the rapid emergence of antibiotic-resistant bacteria (ARB). Wild animals may enable the spread of pathogenic and non-pathogenic ARB when they are exposed to reservoirs (e.g., contaminated soil, water, or crops) and carry ARB in and on their bodies to other environments. We tested for the presence of ARB in four songbird species in southwest Michigan across a gradient of land use. Our specific objectives were to: 1) quantify the prevalence of ARB found in the gut microbiome of birds; 2) identify the specific bacteria exhibiting resistance; 3) assess whether ARB prevalence and identity varied among bird species; and 4) assess whether anthropogenic land use influenced the prevalence and identity of ARB found on birds. We sampled birds across a land use gradient consisting of urban, agricultural, and natural land covers using a randomized, spatially-balanced sampling design and cultured bacteria from fecal samples in the presence of three different antibiotics (amoxicillin, tetracycline, and ciprofloxacin). Overall prevalence of ARB was high, with 88% of total birds carrying ARB resistant to one of three antibiotics that we tested. Resistance to amoxicillin was more common (83% of sampled birds) than resistance to tetracycline (15%) or ciprofloxacin (1%). Identified ARB were diverse, and included 135 isolates representing 5 bacterial phyla and 22 genera. There was no effect of land use on ARB prevalence, with 90% of sampled birds captured in rural sites and 85% of sampled birds in urban sites carrying ARB. We provide the first analysis of ARB prevalence across multiple bird species and land uses utilizing a spatially-balanced, randomized study design. Our results demonstrate that nearly all sampled birds carried at least some ARB, and that they may serve as important dispersal agents of ARB across large spatial scales.
抗生素在人类和兽医医学中的广泛使用来治疗病原菌已导致抗生素耐药菌（ARB）的迅速出现。野生动物在接触到储层（例如受污染的土壤、水或作物）时，可能会携带 ARB 并将其带入和带到其他环境中，从而使病原菌和非病原菌的 ARB 传播。我们在密歇根州西南部的四个鸣禽物种中测试了 ARB 的存在情况，这些物种跨越了土地利用的梯度。我们的具体目标是：1）量化鸟类肠道微生物组中发现的 ARB 的流行率；2）确定具有抗性的特定细菌；3）评估 ARB 流行率和种类在不同鸟类物种之间的差异；4）评估人为土地利用是否会影响鸟类上发现的 ARB 的流行率和种类。我们使用随机、空间平衡的采样设计，在城市、农业和自然土地覆盖的土地利用梯度上采样鸟类，并在三种不同抗生素（阿莫西林、四环素和环丙沙星）存在的情况下从粪便样本中培养细菌。ARB 的总体流行率很高，我们测试的三种抗生素中有 88%的鸟类携带 ARB 耐药。对阿莫西林的耐药性（83%的采样鸟类）比四环素（15%）或环丙沙星（1%）更为常见。鉴定出的 ARB 种类繁多，包括代表 5 个细菌门和 22 个属的 135 个分离株。土地利用对 ARB 流行率没有影响，85%的城市采样鸟类和 90%的农村采样鸟类携带 ARB。我们利用空间平衡、随机研究设计首次分析了多种鸟类和土地利用中的 ARB 流行率。我们的结果表明，几乎所有采样的鸟类都携带至少一些 ARB，它们可能是 ARB 在大空间尺度上传播的重要扩散剂。
