Molecular Characterization and Genetic Diversity of ESBL-Producing Escherichia coli Colonizing the Migratory Franklin's Gulls (Leucophaeus pipixcan) in Antofagasta, North of Chile
Molecular Characterization and Genetic Diversity of ESBL-Producing Escherichia coli Colonizing the Migratory Franklin's Gulls (Leucophaeus pipixcan) in Antofagasta, North of Chile
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DOI：
10.1089/mdr.2014.0158
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发表时间：
2015-02-01
影响因子：
2.6
通讯作者：
Silva, Juan
中科院分区：
文献类型：
--
作者：
Baez, John;Hernandez-Garcia, Marta;Silva, Juan
野生动物，特别是候鸟，在地理上遥远的生态系统之间传播抗生素抗性细菌的作用通常被低估。这项工作的目的是表征富兰克林海鸥粪便中的大肠杆菌群体，重点关注产生超广谱 β-内酰胺酶 (ESBL) 的菌株。 2011年夏天，我们收集了124份从美国和加拿大迁徙到智利北部安托法加斯塔海岸的海鸥粪便拭子（每只一只）。将样品接种在补充有2μg/ml头孢噻肟的MacConkey琼脂上，并通过双盘ESBL协同试验测试来自每个平板的单个菌落的ESBL产生。通过纸片扩散法测定抗生素敏感性，并对bla(ESBL)基因进行扩增和测序。通过脉冲场凝胶电泳 (PFGE)-XbaI 和多位点序列分型探索分离株的遗传多样性。总共鉴定出 91 株具有高抗生素耐药率的大肠杆菌分离株。未检测到碳青霉烯酶的产生，而 91 个分离株中的 67 个 (54%) 由于存在 CTX-M-15 (61.3%)、CTX-M-2 (19.3%)、CTX-M-22 (16.1%) 和 CTX-M-3 (1.6%) 编码基因而表现出 ESBL 表型。观察到较高的遗传多样性，有 30 种 PFGE 模式和 23 种序列类型 (ST)，包括 ST131 (18%)、ST44 (15%)、ST617 (9%) 和 ST10 (9%)。这里提供的结果是对 Hernandez 等人之前报道的结果的补充。属于同一海鸥种类，但位于智利中部地区。在这两个地区的海鸥之间观察到的差异使我们推测，来自北部地区的海鸥作为肠道携带者保留了在美国和/或加拿大获得的耐药细菌。
The role of wild animals, particularly migratory birds, in the dissemination of antibiotic-resistant bacteria between geographically distant ecosystems is usually underestimated. The aim of this work was to characterize the Escherichia coli population from Franklin's gull feces, focusing on the extended-spectrum beta-lactamase (ESBL)-producing strains. In the summer of 2011, 124 fecal swabs from seagulls (1 of each) migrating from the United States and Canada to the coast of Antofagasta, north of Chile, were collected. Samples were seeded on MacConkey agar supplemented with 2 mu g/ml of cefotaxime and a single colony from each plate was tested for ESBL production by the double-disk ESBL synergy test. Antibiotic susceptibility was determined by the disk diffusion method and bla(ESBL) genes were amplified and sequenced. The genetic diversity of isolates was explored by pulsed-field gel electrophoresis (PFGE)-XbaI and multilocus sequence typing. A total of 91 E. coli isolates with high rates of antibiotic resistance were identified. Carbapenemase production was not detected, whereas 67 of the 91 (54%) isolates exhibited an ESBL phenotype due to the presence of CTX-M-15 (61.3%), CTX-M-2 (19.3%), CTX-M-22 (16.1%), and CTX-M-3 (1.6%) coding genes. High genetic diversity was observed, with 30 PFGE patterns and 23 sequence types (STs), including ST131 (18%), ST44 (15%), ST617 (9%), and ST10 (9%). Results presented here are complementary to those previously reported by Hernandez et al. in the same gull species, but located in the Central Region of Chile. Differences observed between gulls from both areas lead us to hypothesize that gulls from the northern location retain, as gut carriers, those resistant bacteria acquired in the United States and/or Canada.