Abstract: 【Abstract】Objective To assess the transfer of bacteria DNA across cellulose triacetate(CTA, low-flux) and polysulfone(low-flux) membranes. Methods Two groups based on the dialyzer of different membrane were used in this study. Experiments were carried out in saline-saline model. The dialysate was contaminated with E.Coli at 4 levels(2.06×102，1.603×103，2.671×103，1.336×104cells/ml), in vitro dialysis was performed under diffusive condition for 4 hours. ultraviolet spectrophotometry and LAL test were used respectively to detect bacteria DNA and endotoxin level in blood side samples. Comparing the difference of bacteria DNA levels in blood side samples between two groups. Results Dialysate challenged with E.Coli at 4 levels, Increased bacteria DNA concentration were observed in all blood side samples, whereas LAL negative after 4-hour dialysis. Bacteria DNA concentration in blood side samples increased along with the elevated extent of E.Coli in dialysate. E.Coli level in dialysate from 103～104cells/ml, higher bacteria DNA concentrations were observed in 130G group than in F6hps group. The difference is significant between them(P<0.05). Conclusion Under identical conditions for two dialyzers, bacteria DNA have better permeabitlity across membrane than endotoxin. CTA low-flux dialyzer has more permeability of bacteria DNA than Polysulfone low-flux dialyzer.

Key words: bacteria DNA, cellulose triacetate membrane, polysulfone membranes, endotoxin