Quantitative Secretome Analysis Of Polymyxin B And Ciprofloxacin Resistance In Escherichia Coli

Bacterial resistance has become a serious threat to human health.Quinolones are one of the most widely used antibiotics in clinical practice.The quinolones resistance of bacteria is a threat that cannot be ignored.In particular,with the gradual development of resistance to polymyxin,the last line of defense for human infections is also under treat.Secreted proteins contribute to the interactions between bacteria and the environment.In this study,we compared the secretomes of polymyxin B-resistant and ciprofloxacin-resistant Escherichia coli strains with that of sensitive strains by data-independent acquisition mass spectrometry,respectively.The study found that compared with sensitive strains,both resistant Escherichia coli not only showed an improved antioxidant capacity by reducing the content of free iron ions,reducing the accumulation of peroxides and repairing damaged proteins,but also a significantly reduced mobility ability by reducing flagella synthesis.In addition,polymyxinresistant bacteria reduce the binding of polymyxin with lipid A by changing the composition of the cell wall.The ciprofloxacin-resistant bacteria reduce the transmembrane transport capacity,including decreasing the intake of polypeptides and the content of membrane pore proteins to reduce their own metabolic rate and the intake of ciprofloxacin,thereby improve tolerance capability.We found a potential molecular target(Yeb V)in polymyxin-resistant bacteria-specific expressed proteins.This work clarifies the secretome changes associated with the acquisition of polymyxin and ciprofloxacin resistance and may contribute to drug development.