[Effects of Three Commonly Used Herbicides on Bacterial Antibiotic Resistance]

The spread of antibiotic resistance has become a serious threat to global public health. Recently, several studies have found that non-antibiotic chemicals can promote the generation and spread of bacterial antibiotic resistance. However, the effects of herbicides on the antibiotic resistance of bacteria remain unclear. In this study, Escherichia coli DH5α was used as the model strain to explore the effects of three commonly used herbicides (glyphosate, glufosinate, and dicamba) on the antibiotic resistance under soil environmental concentrations. The results showed that herbicide exposure affected the sensitivity of E. coli DH5α to antibiotics and significantly improved the resistance of E. coli DH5α to gentamicin (glyphosate > dicamba > glufosinate). After 30 d of herbicide exposure, the E. coli mutant strains enhanced the resistance to tetracycline, chloramphenicol, and aminoglycoside antibiotics, and the minimum inhibitory concentration of streptomycin was increased by 19.8 times. The whole-genome sequencing results illustrated that herbicides induced several previously well-characterized mutations associated with membrane proteins (ompF and papC), fimbriae proteins (yraH), and ribosomes (rpsL) related to antibiotic resistance. Together, the results showed that herbicides can enhance the antibiotic resistance of bacteria via inducing genetic mutations, thereby promoting the potential risk of the spread of antibiotic resistance genes in the environment.