A comparative study of characteristics of current-type and conventional-type cationic bactericides

We have synthesized new polycationic bactericides, poly[oxyethylene(dimethy liminio)trimethylene(dimethyliminio)ethylene dichloride] (OXD) and poly(hex amethyleneguanidine phosphate) (HEP), in order to develop more active but l ess skin-irritative bactericides. The effects of these bactericides on Pseu domonas aeruginosa, Escherichia coli, Serratia marcescens, Klebsiella pneun ioniae, methicillin resistant Staphylococcus aureus (MRSA) and the degree o f their irritations on skin were compared with those of a widely used low m olecular-weight cationic bactericide, benzalkonium chloride (BAC), and a po lycationic bactericide, poly[2-hydroxyethylene(dimethyliminio)methylene chl oride] (2HYC). The minimum bactericidal concentration (MBC) of OXD for 10 m in contact incubation was 16 mug/ml against P aeruginosa, E. coli, S. marce scens and K. pneumoniae, and > 1000 mug/ml against MRSA. The MBC of HEP for 10 min contact incubation was 16 mug/ml against P aeruginosa, 32,mug/ml ag ainst E. coli and K. pneumoniae, and 64,mug/ml against S. marcescens and MR SA. Itch, edema, erythema, heat, injury, desquamation and keratinization ca used by skin irritation were examined in 21 subjects by patch tests. Only o ne subject treated with OXD experienced edema, and one subject with HEP exp erienced keratinization. However, BAC caused itch in 3 subjects, edema in 1 , erythema in 10 and desquamation in 2, indicating that the incidence of sk in irritation of BAC was higher than that of OXD or HER OXD and HEP had ste rilization ability similar to BAC, however, they were less skin-irritative than BAC. This indicates that OXD and HEP can be used as safe bactericides.