Risk Assessment of Horizontal Gene Transfer of ARGs Across Species under Antibiotic Stress

• 1、School of Environmental Science and Engineering, Guangdong University of Technology
• 2、Instrumental Analysis Center of Guangdong University of Technology

Abstract：Under antibiotic stress, the pattern and mechanism of transmission of resistance genes (ARGs) through horizontal gene transfer (HGT) mediated by mobile genetic elements (MGEs) among bacterial species are still unclear, and there is still a large gap in the study of the risk of migration of pathogenic bacteria in hotspot environments, such as farming wastewater, in particular. In this paper, we selected multidrug-resistant Shigella flexneri HL isolated from farming wastewater as the recepient and E. coli MG1655, a red-green bifluorescent bacterium containing RP4 plasmid, as the donor, and constructed a conjugative transfer system, analysed the growth curves, the frequency of conjugative transfer, and the changes of ARGs and intI1 under the stress of β-lactams and sulfonamides antibiotics. The results showed that low concentrations of sulfonamide antibiotics inhibited the growth of donor and recipient bacteria within 6-8h. Amoxicillin (AMX) promoted the conjugative transfer frequency most significantly (57.25%). sul1 relative abundance results indicated that antibiotic stress did not necessarily induce the production of the corresponding ARGs, and the relative abundance of the integrator intI1 decreased with the increase of exposure concentration. Therefore, attention needs to be paid to the ability of pathogenic bacteria to acquire ARGs through conjugative transfer to control the ecological risk of ARGs.

Keywords： Antibiotics Antibiotic resistance genes Horizontal gene transfer Plasmids Antibiotic resistance bacteria