Exploration Of The Role On OmpW In Cronobacter Sakazakii Under Environmental Stresses

Cronobacter sakazakii is an opportunistic foodborne pathogen associated with neonatal bacterial meningitis,necrotizing enterocolitis and bacteremia with high mortality rate ranging from 40% to 80% through the comsumption of powdered infant formula.C.sakazakii contamination in powdered infant formula is of great concern for public health,especially for infant health.C.sakazakiiis widely distributed in the environments and can tolerate to various environmental stresses.To date,there is little information about thetolerance mechanism to various stresses of Cronobacter sakazakii.In addition,OmpW has been shown to be associated with bacterial resistance to herbicides,antibiotics,osmotic stress,and hypoxia.However,OmpW on the response mechanism of C.sakazakiito stresses were poorly understood.In this study,we established a model of C.sakazakiiwild-type(WT)strain andΔOmpW mutant under different stresses(osmotic stress,oxidative stress,neomycin sulfate stress)through the observation of changes of bacteria and biofilm to explore the role on OmpW under environmental stresses in C.sakazakii.The viability of bacteria,the motility,and biofilm formation using the crystal violet staining were determined.In addition,biofilm formation under various stresses was also detected by confocal laser scanning microscopy and scanning electron microscopy.The results indicated that WT and ΔOmpW strains under the different stresses(osmotic stress,oxidative stress,and neomycin sulfate stress)have significant differences in survival rates and biomass of biofilms.Furthermore,cell surface morphology and surfaces of biofilms were also substantially changed.This study indicated that OmpW played an important role on stress resistance of C.sakazakii.The findings in this study provide a new enlightment for prevention and control of food(especially infant formula milk)pollution caused by Cronobacter sakazakii.