The Antibacterial Activity And Mechanism Of Sodium Selenite Against Pseudomonas Aeruginosa

Pseudomonas aeruginosa,an opportunistic pathogen,is widely found in a variety of hosts,including humans,animals and plants.With the widespread use of antibiotics in recent years,multi-drug resistant strains appear constantly.Therefore,it is urgent to develop new antimicrobial drugs and treatment strategies.Selenium is an essential microelement,which has antioxidant and antibacterial functions,and is widely used in dietary supplement and chemoprevention therapy.Previous studies have shown that selenium compounds have potential application value in clinical antiinfection therapy,but its antibacterial mechanism is still unclear.In this study,the antibacterial properties and mechanisms of sodium selenite on P.aeruginosa PAO1 were investigated.Firstly,the results of bacterial growth showed that sodium selenite had no significant impact on the growth of PAO1 when it was lower than 5m M.The antibiotic sensitivity results showed that sodium selenite significantly enhanced the antibiotic sensitivity of PAO1 both in planktonic and biofilm states.In addition,sodium selenite significantly reduced virulence factors of PAO1,including pyocyanin production,bacterial motilities,and the type Ⅲ secretion system(T3SS).Further investigation showed that the content of reactive oxygen species(ROS)in cells was significantly increased and the expression of antioxidant-related genes decreased which indicated that sodium selenite induced oxidative stress.We also performed RNA-seq analysis on PAO1 with or without sodium selenite treatment,and the results showed that many virulence factors and oxidative stress related genes were differentially expressed.Finally,the Chinese cabbage infection assay showed that the combination of sodium selenite and antibiotics significantly alleviated the infections of PAO1.In summary,the results showed that sodium selenite induced oxidative stress of P.aeruginosa,which in turn enhanced its antibiotics sensitivity and deceased pathogenicity.These findings suggest that sodium selenite may be a potential strategy for adjuvant treatment of P.aeruginosa infections.