[Determination of bactericidal minimum concentrations of 3 antiseptics and 1 disinfectant on 580 hospital gram-negative bacilli].

Abstract

Minimal bactericidal activities (MBCs) of three antiseptics (povidone iodine, chlorhexidine digluconate, benzalkonium chloride) and one disinfectant (sodium hypochloride) where determined, on 580 hospital Gram negative bacilli. Previously the Afnor T 72-150 standard for antiseptic and disinfectant was established for two reference strains E. coli CIP 54 127 and P. aeruginosa CIP A 22. No difference was found between the MBC obtained with these strains in Afnor standard and in microdilution method. Microdilution method allows to test 11 hospital isolates and one reference strain. A strain was considered as resistant when the MBC was one dilution higher than the reference strain MBC. Results were as follows: None strain was resistant to sodium hypochloride and povidone iodine; 18.2% Enterobacteriaceae were resistant to chlorhexidine digluconate with 94.2% of Proteus; 4% of Enterobacteriaceae were resistant to benzalkonium chloride with 89.5% of Proteus and only 1.8% other bacilli. Results obtained in the present study are similar as those previously published particularly with Proteus; nevertheless other studies have reported P. aeruginosa strains resistant to chlorhexidine digluconate and benzalkonium chloride; this last point was not observed in our study.