Campylobacter jejuni (C. jejuni) is the leading cause of bacterial food poisoning in Japan.In addition, it is known that the use of antibacterial agents in livestock breeding is increasing the number of resistant bacteria.In Japan, antimicrobial resistance surveillance in livestock animals is conducted to monitor bacteria that cause human diseases, and C. jejuni is also being investigated for antimicrobial resistance.However, the large scale investigations of C. jejuni that caused disease in humans and how drug resistance is acquired were unclear.

　In this study, we extracted the genomic DNA of 2015 strains that caused food poisoning in Toyama Prefecture from 2019 to 116, and focused on the "length" and "accuracy" of the sequences, which had been difficult to achieve in the past. The complete genome sequence was obtained by combining two standardized DNA sequencing technologies (Illumina sequencer and Nanopore sequencer).

　The present study revealed that one of the strains of C. jejuni previously reported in Japan continues to be prevalent, and that the plasmid that confers resistance to C. jejuni (exists independently of the chromosome). It was clarified that drug resistance is improved by the structure of circular DNA) and, in part, by an increase in the resistance gene on the plasmid.

　As a result, surveillance of drug resistance in livestock animals and monitoring by genome analysis will continue to be important. Further analysis is expected to suppress drug-resistant C. jejuni.

Paper information:[Microbiology spectrum] Whole-Genome and Plasmid Comparative Analysis of Campylobacter jejuni from Human Patients in Toyama, Japan, from 2015 to 2019