RESUMO
2% glutaraldehyde is the reference disinfectant for hospital instruments. However, its high environmental toxicity makes desirable to search for alternatives. We compare the antimicrobial activity of 2% glutaraldehyde with 0.44% N-duopropenide (NDP), 0.66% NDP in 48 degrees alcoholic solution (NDP-alc), 0.13% glutaraldehyde-phenate, 1% or 3% persulphate (Virkon) and 0.1% or 0.5% chlorhexidine, using a model that mimics non-regular surface instruments contaminated with microbial strains (44 bacteria, 6 of which were Mycobacterium). The contaminated carrier is soaked in the disinfectant solution. After 5 or 20 minutes contact the disinfectant is neutralized. The overall results on all microorganisms in 20 minutes, show similar antibacterial activity for 2% glutaraldehyde and 0.66% NDP-alc, followed by 0.44% NDP and after by the two concentrations of Virkon and 0.5% chlorhexidine. The 0.13% glutaraldehyde-phenate and 0.1% chlorhexidine exhibited significantly less effect than any other disinfectant. 0.66% NDP-alc was faster antimicrobial activity than 2% glutaraldehyde, destroying totally the inoculum in 5 minutes. Activity on Mycobacterium showed great differences between 2% glutaraldehyde and the rest of products (> 5 log versus < 3 log reduction in 20 minutes), with an exception: NDP-alc, with similar and faster activity (> 5 log in 5 minutes) than 2% glutaraldehyde. With human blood, the survival microorganisms increase 0.3 log (average) in all the disinfectants used. The aggressiveness on metallic devices was greater in Virkon than in the other disinfectants. We conclude that NDP (alone or in alcoholic solution) may be a good alternative to glutaraldehyde in hospital instruments disinfection.