Multilocus sequence typing and drug resistance analysis of Yersinia enterocolitica in raw meat products in some areas of Liaoning Province

Abstract:

[Background] Yersinia enterocolitica is a zoonotic bacterium with wide distribution in China and can cause a variety of intestinal symptoms and systemic diseases, posing a threat to human and animal health. [Objective] To understand the drug resistance phenotypes and genes, virulence genes, and multilocus sequence typing of Y.enterocolitica isolated from different raw meat sources in Liaoning Province. [Methods] A total of 26 strains of Y.enterocolitica were isolated from raw chicken, raw pork, and raw beef samples in Liaoning Province from 2018 to 2021. The drug sensitivity test and serotyping were carried out, and whole genome sequencing was conducted to reveal the genetic information of the strains. [Results] The 26 strains of Y.enterocolitica had the highest resistance to cefazolin. All the 26 strains were intermediately resistant to polymyxin E and sensitive to chloramphenicol and gentamicin. The virulence genes of the 26 strains were mainly ail⁻virF⁻yadA⁻ystA⁻ystB⁺, and there was a strain with the genotype of ail⁺virF⁻yadA⁻ystA⁺ystB⁻, which was from a pork sample. Most of the strains presented the serotype of O:5, accounting for 84.6%, and the strains with the serotype of O:8 and unserotyped accounted for 7.7%. All the 26 strains carried the same resistance genes of CRP, rosA, and rosB. Fourteen strains carried vat(F) and blaA, and 2 strains carried qnrD. A total of 21 sequence types (ST) were obtained by multilocus sequence typing, of which ST150, ST726, ST848, ST143, and ST820 each had two strains, and the remaining STs each had one strain. The STs of the same cluster had the same virulence genes and drug resistance genes. [Conclusion] The STs of Y.enterocolitica from different raw meat samples in Liaoning Province present scattered distribution and carry multiple drug resistance genes, posing a risk of drug resistance.

Key words:Yersinia enterocolitica;drug resistance gene;whole genome sequencing;multilocus sequence typing;drug resistance phenotype