Application of biofertilizers increases fluoroquinolone resistance in Vibrio parahaemolyticus isolated from aquaculture environments.

Antimicrobial resistance genes in aquaculture environments have attracted wide interest, since these genes pose a severe threat to human health. This study aimed to explore the possible mechanisms of the ciprofloxacin resistance of Vibrio parahaemolyticus (V. parahaemolytiucs) in aquaculture environments, which may have been affected by the biofertilizer utilization in China. Plasmid-mediate quinolone resistance (PMQR) genes, representative (fluoro)quinolones (FNQs), and ciprofloxacin-resistance isolates in biofertilizer samples were analyzed. The significantly higher abundance of oqxB was alarming. The transferable experiments and Southern blot analysis indicated that oqxB could spread horizontally from biofertilizers to V. parahaemolyticus , and two (16.7%) trans -conjugants harboring oqxB were provided by 12 isolates that successfully produced OqxB. To the best of our knowledge, this study is the first to report PMQR genes dissipation from biofertilizers to V. parahaemolyticus in aquaculture environments. The surveillance, monitoring and control of PMQR genes in biofertilizers are warranted for seafood safety and human health. • The prevalence of PMQR determinants in biofertilizers was first investigated. • The abundance of oqxB gene in biofertilizer is significantly high. • The dissipation of oqxB from biofertilizers to Vibrio was first discovered. • ARGs in biofertilizer could pose a risk in seafood safety and public health. [ABSTRACT FROM AUTHOR]