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Abstract：
Extended-spectrum β-lactamase-producing Escherichia coli ST131 has become widespread worldwide. This study aims to characterize the virulome, resistome, and population structure of E. coli ST131 isolates from clinical blood samples in Hungary. A total of 30 C2/H30Rx and 33 C1-M27 ST131 isolates were selected for Illumina MiSeq sequencing and 30 isolates for MinION sequencing, followed by hybrid de novo assembly. Five C2/H30Rx and one C1-M27 cluster were identified. C1-M27 isolates harbored the F1:A2:B20 plasmid in 93.9% of cases. Long-read sequencing revealed that blaCTX-M-27 was on plasmids. Among the C2/H30Rx isolates, only six isolates carried the C2-associated F2:A1:B- plasmid type. Of 19 hybrid-assembled C2/H30Rx genomes, the blaCTX-M-15 gene was located on plasmid only in one isolate, while in the other isolates, ISEcp1 or IS26-mediated chromosomal integration of blaCTX-M-15 was detected in unique variations. In one isolate a part of F2:A1:B- plasmid integrated into the chromosome. These results suggest that CTX-M-15-producing C2/H30Rx and CTX-M-27-producing C1-M27 subclades may have emerged and spread in different ways in Hungary. While blaCTX-M-27 was carried mainly on the C1/H30R-associated F1:A2:B20 plasmid, the IncF-like plasmids of C2/H30Rx or its composite transposons have been incorporated into the chromosome through convergent evolutionary processes.
摘要：
产超广谱β-内酰胺酶的大肠杆菌ST131已在世界范围内普及。本研究旨在表征病毒组，抗性，和来自匈牙利临床血液样本的大肠杆菌ST131分离株的种群结构。总共选择了30个C2/H30Rx和33个C1-M27ST131分离株用于IlluminaMiSeq测序，选择了30个分离株用于MinION测序，其次是混合从头组装。鉴定了五个C2/H30Rx和一个C1-M27簇。C1-M27分离株在93.9%的病例中含有F1:A2:B20质粒。长读数测序显示blaCTX-M-27在质粒上。在C2/H30Rx分离物中，只有六个分离株携带C2相关的F2：A1：B质粒类型。在19个混合组装的C2/H30Rx基因组中，blaCTX-M-15基因仅位于一个分离株的质粒上，而在其他隔离物中，在独特的变异中检测到ISEcp1或IS26介导的blaCTX-M-15的染色体整合。在一个分离物中,部分F2:A1:B-质粒整合到染色体中。这些结果表明，产生CTX-M-15的C2/H30Rx和产生CTX-M-27的C1-M27亚进化枝可能在匈牙利以不同的方式出现和传播。虽然blaCTX-M-27主要在C1/H30R相关的F1:A2:B20质粒上携带，C2/H30Rx或其复合转座子的IncF样质粒已通过趋同进化过程掺入染色体。
