Roberts Marilyn C, No David B, Marzluff John M, Delap Jack H, Turner Robert
Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA.
Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA.
Vet Microbiol. 2016 Oct 15;194:48-54. doi: 10.1016/j.vetmic.2016.01.022. Epub 2016 Feb 3.
Vancomycin-resistant enterococci [VRE] have been isolated from municipal, hospital and agricultural wastewater, recreational beaches, wild animals, birds and food animals around the world. In this study, American crows (Corvus brachyrhynchos) from sewage treatment plants (WWTP), dairy farms, and a large roost in a restored wetland with corresponding environmental samples were cultured for VRE. A total of 245 samples [156 crows, 89 environmental] were collected and screened for acquired vanA, vanB and/or intrinsic vanC1 genes. Samples were enriched overnight in BHI supplemented with 20μg/mL aztreonam, 4μg/mL vancomycin and plated on m-Enterococcus agar media supplemented with 6μg/mL vancomycin. Selected colonies were grown on BHI media supplemented with 18μg/mL vancomycin. Of these, 24.5% of the crow and 55% the environmental/cow samples were VRE positive as defined by Enterococcus spp. able to grow on media supplemented with 18μg/mL vancomycin. A total of 122 VRE isolates, 43 crow and 79 environmental isolates were screened, identified to species level using 16S sequencing and further characterized. Four vanA E. faecium and multiple vanC1 E. gallinarum were identified from crows isolated from three sites. E. faecium vanA and E. gallinarum vanC1 along with other Enterococcus spp. carrying vanA, vanB, vanC1 were isolated from three environments. All enterococci were multidrug resistant. Crows were more likely to carry vanA E. faecium than either the cow feces or wetland waters/soils. Comparing E. gallinarum vanC1 from crows and their environment would be useful in determining whether crows share VRE strains with their environment.
耐万古霉素肠球菌（VRE）已在世界各地的城市、医院及农业废水中被分离出来，也在休闲海滩、野生动物、鸟类和食用动物中被发现。在本研究中，对来自污水处理厂（WWTP）、奶牛场以及一处恢复湿地中的大型鸦群的美洲鸦（短嘴鸦），以及相应的环境样本进行了VRE培养。共收集了245个样本（156只乌鸦、89个环境样本），并对其进行检测，以确定是否存在获得性vanA、vanB和/或固有vanC1基因。样本在添加了20μg/mL氨曲南、4μg/mL万古霉素的脑心浸液（BHI）中富集过夜，然后接种在添加了6μg/mL万古霉素的m-肠球菌琼脂培养基上。挑选出的菌落接种在添加了18μg/mL万古霉素的BHI培养基上。其中，按照在添加了18μg/mL万古霉素的培养基上能够生长的肠球菌属来定义，24.5%的乌鸦样本和55%的环境/奶牛样本VRE呈阳性。总共对122株VRE分离株（43株乌鸦分离株和79株环境分离株）进行了筛选，利用16S测序将其鉴定到种水平，并进一步进行特征分析。从三个从三个地点分离出的乌鸦中鉴定出了4株vanA粪肠球菌和多株vanC1鹑鸡肠球菌。从三个环境中分离出了粪肠球菌vanA和鹑鸡肠球菌vanC1以及其他携带vanA、vanB、vanC1的肠球菌属。所有肠球菌均具有多重耐药性。乌鸦携带vanA粪肠球菌的可能性比奶牛粪便或湿地水体/土壤更高。比较乌鸦及其环境中的鹑鸡肠球菌vanC1，将有助于确定乌鸦是否与它们所处的环境共享VRE菌株。
