Effect Of Fat Emulsion On The Formation Of Mixed Biofilm On The Surface Of Central Venous Catheter

[Objective]:To explore the effect of lipid emulsion on the surface of central venous catheter in Escherichia coli and Candida albicans Mixed-Species Biofilm form.[Methods]:1. Construction of the outer membrane type of Candida albicans-Escherichia coli mixed biofilm on the surface of central venous catheter. By XTT, crystal violet, laser scanning confocal microscopy, scanning electron microscopy to dynamically monitor the formation process of biofilm.2. At 1%,5%,10%,15%,20% lipid emulsion concentration of Candida albicans Escherichia coli biological hybrid membrane were cultured using the XTT determination of pathogenic bacteria growth kinetics; crystallization violet semi quantitative determination of biofilm formation; live dead staining bacteria using CLSM observation of biofilm in live, dead bacteria distribution; fluorescence in situ hybridization technique to observe the inside the biofilm on the two pathogenic bacteria distribution, structure; scanning electron microscope was used to observe the surface biofilm pathogenic bacteria distribution structure.3. QRT-PCR method was used to detect the expression of Candida albicans of HTA1、iha gene; Escherichia coli of flhDC, hwp1 gene in the mixed biofilm of 10% fat milk..[Results]:1. XTT, the crystal violet test showed that the growth dynamics and formation ability of the biofilm in the positive group were higher than that in the negative group, both of which were higher than that of the single strain group.2. Scanning electron microscope results showed that as the culture time increased, PVC material surface biological structure is being increasingly complex, mixed culture group is formed on the surface of the agglomerate, laminated hybrid biofilm, spores of visible Escherichia coli and Candida albicans hyphae showed overlapping, hybrid growth, white beads bacterium around (spores, pseudo mycelium, mycelium) adhesion a lot of Escherichia coli, forming a complex network structure. And negative mixed group compared to mixed positive group of biological membrane structure is more complex, pathogen relationship more closely.3. Intralipid group mixed biofilm growth dynamic and biofilm forming ability were higher than those of the control group,10% milk fat concentration in the mixed biofilm formation best. Concentrations of lipid emulsion in 5% and above group SEM examination found that, on the surface of PVC material, CA spores, pseudohyphae, mycelium, milk fat composition and E.coil overlapping the compact structure of biofilm formation. Fluorescence in situ hybridization was performed on CLSM observation, inside the biofilm on the two pathogens is overlapping, hybrid growth.4. Culture 24h biofilm fluorescence quantitative PCR results showed that:compared to the control group, the Intralipid group flhDC, iha htal, hwpl genes were obviously up-regulated, respectively times 6.0567, times 22.1474, times 2.3914, 1.7218 times. Cultured 72h biofilm fluorescence quantitative PCR results: compared with the control group, the Intralipid group flhDC, iha, htal, hwpl were down regulated, respectively for 0.0633 times,0.0813 times and times 0.7911 and 0.0706 times.[Conclusion]:1. Escherichia coli of MC1000 and Candida albicans of ATCC10231can form E.Coil-Ca complex mixed biofilm on the surface of PVC material with the bacterial liquid concentration of 1 X 106CFU/mL co cultured with 24h.2. E.Coil-Ca mixed biofilm was more thick and complex than single bacterial cells.3. The experiment confirmed injection with milk fat can promote the formation of E.coil-Ca mixed biofilm,10% milk fat concentration effect best. Milk fat composition and also in the composition of the bacterial biofilm, complicates E.coil-Ca mixed biofilm structure. Biofilm within the two kinds of bacteria were also mixed students long and complex structure.4. The early stage of Fat Emulsions may promote the formation of E.coil-Ca mixed biofilm by up regulation of Escherichia coli flhDC, iha, Candida albicans HTA1, hwpl expression.