Department of Pathobiology, University of Guelph, Guelph, Ontario, Canada.
Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, United Kingdom.
PLoS One. 2022 Mar 16;17(3):e0264439. doi: 10.1371/journal.pone.0264439. eCollection 2022.
Conserved IncI1 and IncHI1 plasmids carrying blaCTX-M-1 have been found circulating in chickens and horses from continental Europe, respectively. In Canada, blaCTX-M-1 is overwhelmingly the most common blaCTX-M variant found in Escherichia coli from chicken and horses and can be recovered at lower frequencies in swine, cattle, and dogs. Whole-genome sequencing has identified a large genetic diversity of isolates carrying this variant, warranting further investigations into the plasmids carrying this gene. Therefore, the objective of this study was to describe the genetic profiles of blaCTX-M-1 plasmids circulating in E. coli from Canadian domestic animals and compare them to those recovered in animals in Europe. Fifty-one blaCTX-M-1 positive E. coli isolates from chicken (n = 14), horses (racetrack horses n = 11; community horses n = 3), swine (n = 7), turkey (n = 6), dogs (n = 5), beef cattle (n = 3), and dairy cattle (n = 2) were selected for plasmid characterization. Sequences were obtained through both Illumina and Oxford Nanopore technologies. Genomes were assembled using either Unicycler hybrid assembly or Flye with polishing performed using Pilon. blaCTX-M-1 was found residing on a plasmid in 45 isolates and chromosomally located in six isolates. A conserved IncI1/ST3 plasmid was identified among chicken (n = 12), turkey (n = 4), swine (n = 6), dog (n = 2), and beef cattle (n = 2) isolates. When compared against publicly available data, these plasmids showed a high degree of similarity to those identified in isolates from poultry and swine in Europe. These results suggest that an epidemic IncI1/ST3 plasmid similar to the one found in Europe is contributing to the spread of blaCTX-M-1 in Canada. A conserved IncHI1/FIA(HI1)/ST2 plasmid was also recovered from nearly all racetrack horse isolates (n = 10). Although IncHI1/ST2 plasmids have been reported among European horse isolates, IncHI1/ST9 plasmids appear to be more widespread. Further studies are necessary to understand the factors contributing to these plasmids' success in their respective populations.
在欧洲大陆，分别从鸡和马中发现了携带 blaCTX-M-1 的保守 IncI1 和 IncHI1 质粒。在加拿大，blaCTX-M-1 是在鸡和马的大肠杆菌中发现的最常见的 blaCTX-M 变体，在猪、牛和狗中也可以以较低的频率回收。全基因组测序确定了携带该变体的分离株具有很大的遗传多样性，因此需要进一步研究携带该基因的质粒。因此，本研究的目的是描述在加拿大家畜大肠杆菌中循环的 blaCTX-M-1 质粒的遗传特征，并将其与在欧洲动物中回收的质粒进行比较。从鸡（n=14）、马（赛马 n=11；社区马 n=3）、猪（n=7）、火鸡（n=6）、狗（n=5）、肉牛（n=3）和奶牛（n=2）中选择了 51 株 blaCTX-M-1 阳性大肠杆菌进行质粒特征描述。通过 Illumina 和 Oxford Nanopore 技术获得序列。使用 Unicycler 混合组装或 Flye 进行基因组组装，并使用 Pilon 进行抛光。在 45 株分离株中发现 blaCTX-M-1 位于质粒上，在 6 株分离株中发现 blaCTX-M-1 位于染色体上。在鸡（n=12）、火鸡（n=4）、猪（n=6）、狗（n=2）和肉牛（n=2）分离株中发现了保守的 IncI1/ST3 质粒。与公开数据相比，这些质粒与在欧洲家禽和猪分离株中发现的质粒高度相似。这些结果表明，类似于在欧洲发现的流行的 IncI1/ST3 质粒正在促进加拿大 blaCTX-M-1 的传播。还从几乎所有赛马马分离株（n=10）中回收了保守的 IncHI1/FIA(HI1)/ST2 质粒。尽管在欧洲马分离株中报道了 IncHI1/ST2 质粒，但似乎 IncHI1/ST9 质粒更为广泛。需要进一步的研究来了解这些质粒在各自种群中成功的因素。
