摘要
       抗生素在人类和兽医学中的广泛应用导致了抗生素耐药菌( ARB )的迅速出现。野生动物暴露于环境(例如受污染的土壤、水或作物)并将ARB携带入其体内和体内运送至其他环境时，可使致病性和非致病性ARB扩散。我们测试了在密歇根州西南部的四种鸣禽物种中ARB的存在情况，并测试了土地利用的梯度。我们的具体目标是: 1 )量化在鸟类肠道微生物组中发现的ARB的流行率；2 )鉴定表现出抗性的特定细菌；3 )评估ARB在鸟类中的流行率和特性是否不同；4 )评估人为土地使用是否影响鸟类ARB的流行和特征。我们采用随机空间平衡抽样设计，在三种抗生素(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，在由城市、农业和自然土地覆盖物组成的土地使用梯度上对鸟类进行抽样。ARB的总体流行率很高，88 %的携带ARB的鸟类对我们测试的三种抗生素之一有耐药性。阿莫西林的耐药率( 83 % )高于四环素( 15 % )和环丙沙星( 1 % )。鉴定的ARB具有多样性，包括135个分离物，代表5个细菌门和22个属。土地利用对ARB患病率没有影响，90 %的采样鸟类在农村地区捕获，85 %的城市采样鸟类携带ARB。我们采用空间平衡的随机研究设计，首次分析了ARB在多种鸟类和土地利用中的流行情况。结果表明，几乎所有采样鸟类都携带至少部分ARB，它们可能是ARB在大空间尺度上的重要扩散媒介。

 
       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.

https://www.sciencedirect.com/science/article/pii/S0048969718303802