School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia, Australia.
Antimicrobial Resistance and Infectious Diseases Laboratory, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia.
J Antimicrob Chemother. 2019 Sep 1;74(9):2566-2574. doi: 10.1093/jac/dkz242.
Antimicrobial resistance (AMR) to critically important antimicrobials (CIAs) amongst Gram-negative bacteria can feasibly be transferred amongst wildlife, humans and domestic animals. This study investigated the ecology, epidemiology and origins of CIA-resistant Escherichia coli carried by Australian silver gulls (Chroicocephalus novaehollandiae), a gregarious avian wildlife species that is a common inhabitant of coastal areas with high levels of human contact.
Sampling locations were widely dispersed around the perimeter of the Australian continent, with sites separated by up to 3500 km. WGS was used to study the diversity and molecular characteristics of resistant isolates to ascertain their epidemiological origin.
Investigation of 562 faecal samples revealed widespread occurrence of extended-spectrum cephalosporin-resistant (21.7%) and fluoroquinolone-resistant (23.8%) E. coli. Genome sequencing revealed that CIA-resistant E. coli isolates (n = 284) from gulls predominantly belonged to human-associated extra-intestinal pathogenic E. coli (ExPEC) clones, including ST131 (17%), ST10 (8%), ST1193 (6%), ST69 (5%) and ST38 (4%). Genomic analysis revealed that gulls carry pandemic ExPEC-ST131 clades (O25:H4 H30-R and H30-Rx) and globally emerging fluoroquinolone-resistant ST1193 identified among humans worldwide. Comparative analysis revealed that ST131 and ST1193 isolates from gulls overlapped extensively with human clinical isolates from Australia and overseas. The present study also detected single isolates of carbapenem-resistant E. coli (ST410-blaOXA-48) and colistin-resistant E. coli (ST345-mcr-1).
The carriage of diverse CIA-resistant E. coli clones that strongly resemble pathogenic clones from humans suggests that gulls can act as ecological sponges indiscriminately accumulating and disseminating CIA-resistant bacteria over vast distances.
革兰氏阴性菌对抗菌药物至关重要的抗药性（AMR）可能在野生动物、人类和家养动物之间传播。本研究调查了澳大利亚银鸥（Chroicocephalus novaehollandiae）携带的耐关键抗菌药物（CIA）大肠埃希氏菌的生态学、流行病学和来源，银鸥是一种群居的野生鸟类，是人类经常接触的沿海地区的常见居民。
采样地点分布在澳大利亚大陆周边，地点之间相隔最远可达 3500 公里。使用 WGS 研究了耐药分离株的多样性和分子特征，以确定其流行病学来源。
对 562 份粪便样本的调查显示，广泛存在对第三代头孢菌素（21.7%）和氟喹诺酮类（23.8%）耐药的大肠埃希氏菌。基因组测序显示，从海鸥中分离出的 CIA 耐药大肠埃希氏菌（n=284）主要属于与人类相关的肠外致病性大肠埃希氏菌（ExPEC）克隆，包括 ST131（17%）、ST10（8%）、ST1193（6%）、ST69（5%）和 ST38（4%）。基因组分析显示，海鸥携带流行的 ExPEC-ST131 克隆（O25：H4 H30-R 和 H30-Rx）和全球范围内出现的对氟喹诺酮类耐药的 ST1193，这在世界各地的人类中都有发现。比较分析显示，从海鸥中分离出的 ST131 和 ST1193 与澳大利亚和海外的人类临床分离株有广泛的重叠。本研究还检测到耐碳青霉烯类大肠埃希氏菌（ST410-blaOXA-48）和多粘菌素耐药大肠埃希氏菌（ST345-mcr-1）的单个分离株。
携带与人类致病性克隆相似的多种 CIA 耐药大肠埃希氏菌克隆表明，海鸥可以作为生态海绵，不加区分地在远距离积累和传播 CIA 耐药细菌。
