Bactericidal activity of 3 cutaneous/mucosal antiseptic solutions in the presence of interfering substances: Improvement of the NF EN 13727 European Standard?

OBJECTIVE: There is no standard protocol for the evaluation of antiseptics used for skin and mucous membranes in the presence of interfering substances. Our objective was to suggest trial conditions adapted from the NF EN 13727 standard, for the evaluation of antiseptics used in gynecology and dermatology. METHODS: Three antiseptic solutions were tested in vitro: a chlorhexidine-benzalkonium (CB) combination, a hexamidine-chlorhexidine-chlorocresol (HCC) combination, and povidone iodine (P). The adaptation of trial conditions to the standard involved choosing dilutions, solvent, and interfering substances. The activity of solutions was assessed on the recommended strains at concentrations of 97% (pure solution), 50%, and 10% (diluted solution), and 1%. A logarithmic reduction ≥ 5 was expected after 60seconds of contact, to meet requirements of bactericidal activity. RESULTS: HCC did not present any bactericidal activity except on P. aeruginosa at a concentration of 97%. P was not bactericidal on E. hirae at any concentration and on S. aureus at 97%. CB had the most homogeneous bactericidal activity with a reduction>5 log on the 4 bacterial strains at concentrations of 97%, 50% and 10%. CONCLUSION: Adapting the NF EN 13727 standard allowed assessing the 3 tested solutions: only CB was bactericidal in dirty conditions. This study proved the possibility of validating antiseptic choice in vitro, in current practice conditions, for adjunctive treatment of skin and mucous membranes disorders, primarily of bacterial origin or with a potential of superinfection.

Activity of Drill® lozenges on the main microorganisms responsible for upper respiratory tract infections.

OBJECTIVES: The treatment of sore throat, considered to be essentially due to viral infection, does not require the use of antibiotics. The recommended treatment is therefore based on the use of topical anaesthetics and antiseptics. Throat lozenges play a leading role in topical treatment by allowing immediate, massive and persistent release of the active molecule at the site of infection. The objective of this study was to demonstrate the short-term and long-term in vitro antimicrobial efficacy of Drill(®) lozenges in relation to the main pathogens responsible for upper respiratory tract infections. MATERIAL AND METHOD: The bactericidal and virucidal activity in relation to the main microorganisms responsible for upper respiratory tract infections, including the H1N1 influenza virus, was evaluated after short (5 minutes) and long (3h) contact times, according to a methodology complying with European standards for the evaluation of chemical antiseptics and disinfectants. In parallel, the global antibacterial activity was determined on 30 strains representative of the resident flora by determination of maximum inhibitory dilutions (MID) and maximum bactericidal dilutions (MBD). RESULTS: Drill(®) lozenges presented an antibacterial activity inducing significant (>90%) destruction of the main upper respiratory tract pathogens after a 5-minute contact time at high concentration and after a 3-hour contact time after dilution. Drill(®) lozenges also exerted an antiviral activity inducing 2 log (99%) destruction of the H1N1 virus after a 5-min contact time at high concentration, with maintenance of this activity after dilution (3h). A homogeneous antibacterial activity was observed on the resident flora. CONCLUSION: These in vitro tests confirm the value of chlorhexidine lozenges in the treatment of upper respiratory tract infections such as sore throat.