Effect of disinfectant on log10 reduction of viable organisms on NC internal surfaces + valve effluent following valve activation, using standard inoculation protocol or NCs pretreated with complement-inactivated human serum and exposed to Staphylococcus epidermidis for 18 h prior to disinfection treatment. AS, alcohol scrubbing, standard protocol; AS + S, alcohol scrubbing, serum pretreatment/extended inoculation; PS, povidone-iodine scrubbing, standard protocol; PS + S, povidone-iodine scrubbing, serum pretreatment/extended inoculation; CS, chlorhexidine gluconate + isopropanol scrubbing, standard protocol; CS + S, chlorhexidine gluconate + isopropanol scrubbing, serum pretreatment/extended inoculation. Error bars, ±1 standard deviation. AS, PS, n = 10; CS, AS + S, n = 9; PS + S, CS + S, n = 6. *, P < 0·05, T-test only.