COMPARATIVE STUDY OF BACTERICIDAL ACTIVITIES OF SIX DIFFERENT DISINFECTANTS

Bactericidal activities of six commonly used disinfectants against scven different species of clinically isolatcd hacteria, mainly glucose-nonfermentative Gram-negative hacilli, were compared. In terms of mean values of the minimum hactericidal concentration (M BC), henzethonium chloride showed the highest efficacy, followed in order hy chlorhexidine gluconate, alkyldiaminoethylglycine hydrochloride, glutaraldehyde, povidone-iodine, and phenol. However, mean MBCs of henzethonium chloride, alkyldiaminoethylglycine hydrochloride and chlorhexidine gluconate against individual species covered a far wider range from species to species compared with those of the other three disinfectants. In addition, hactericidal activities of the ahove-mentioned three disinfectants against Pseudomonas cepacia and Achrolllohaetcr xrlosoxidans ranged more widely from strain to strain than against other species. When the minimum concentrations of individual disinfectants recommended for hospital use hy the manufacturers were used, chlorhexidine gluconate (0.02%), alkyldiaminoethylglycine hydrochloride (0.1%), henzethonium chloride (0.1%) and povidone-iodine (0.75%) were not hactericidal to definite numhers of hacterial strains tested. Among them, chlorhexidine gluconate at the concentration recommended was ineffective against many strains of all hacterial species tested, especially against strains of glucose-nonfermentative Gram-negative hacilli except for PseW/O/llOllaS aerugillosa. Alkyldiamino­ ethylglycine hydrochloride was also remarkahly ineffective against StaphylococcusaI/reus and P. cepacia. Among all the species tested, P. cepacia showed the strongest resistance to the disinfectants tested at the minimum concentrations of individual disinfectants recommended for hospital use hy the manufacturers.