Comparison of disinfective power according to application order of 70% isopropyl alcohol and 10% povidone-iodine

BACKGROUND Many disinfectants have been used clinically in both single and combination applications, but there have been few studies on disinfective power according to sterilization sequence when using a combination of disinfectants. The purpose of this study was to evaluate the disinfective power of a combination of 70% isopropyl alcohol and 10% povidone-iodine (PVP-I) according to sterilization sequence. METHODS Two hundred healthy volunteers were recruited. Subjects were disinfected with a combination of 70% isopropyl alcohol and 10% PVP-I on both forearms, in varying sequence. The AP group included disinfections on the left forearm with isopropyl alcohol first followed by 10% PVP-I, while the PA group included disinfections on the right forearm with same disinfectants in reverse order. Skin cultures were obtained using cotton swabs 3 min after application of each disinfectant, and then were inoculated on blood agar plates for bacterial culture. Cultures were incubated at 37℃ under aerobic conditions for 48 hours. RESULTS There was no significant difference in the number of positive cultures after the 1(st) disinfection (AP, 45; PA, 36, P = 0.262) or the 2(nd) disinfection (AP, 6; PA, 13, P = 0.157), suggesting that there is no relationship between disinfective power and the sequence of the disinfectants used. The number of positive cultures significantly decreased after the 2(nd) disinfection (P < 0.01), however. CONCLUSIONS There was no significant difference in disinfective power according to sterilization sequence with 70% isopropyl alcohol and 10% PVP-I in healthy volunteers. The combination of 70% isopropyl alcohol and 10% PVP-I was more effective than disinfection with a single agent regardless of sterilization sequence.