title: Efficacy of dental unit waterlines disinfectants on a polymicrobial biofilm.
abstract: Due to their high surface-volume ratio, their laminar flow and frequent stagnation periods, dental unit waterlines (DUWL) foster the attachment of microorganisms and the development of biofilm, resulting in the continuous contamination of the outlet water from dental units; this contamination may be responsible for a potential risk of infection due to the exposure of patients and medical staff to droplet inhalation or splashed water. In this study, the anti-biofilm activity of three disinfectants recommended by dental unit manufacturers -Calbenium(©), Oxygenal 6(©) and Sterispray(©) - was evaluated. A dynamic model simulating DUWL conditions was developed and polymicrobial biofilms containing bacteria (Pseudomonas aeruginosa), fungi (Candida albicans) and Free Living Amoeba (FLA: Vermamoeba vermiformis) were allowed to form. The ability of disinfectants to reduce biofilm formation or to eradicate an already formed biofilm was evaluated. Results showed the various effects of the tested disinfectants according to their composition, concentration and the targeted species. V. vermiformis was resistant to disinfectants, regardless of the tested concentrations and the concentrations recommended by manufacturers were not the most appropriate. Results also showed that Calbenium(©) was the most effective disinfectant to reduce already formed biofilms; its maximum efficiency was observed from 0.5% on both P. aeruginosa and C. albicans compared to 2 and 3% respectively for Sterispray(©). The maximum efficiency of Oxygenal(©) was observed from 3% on P. aeruginosa but Oxygenal(©) was unable to totally eliminate C. albicans in the tested conditions, contrary to other disinfectants. Calbenium(©) was able to prevent biofilm formation efficiently even if it displayed no prophylactic activity against V. vermiformis. Overall, the FLA survival may contribute to maintaining other species. Finally the tested disinfectants were partially active against sessile microorganisms and more suitable concentrations could be used to increase their efficacy. Their use in a prophylactic rather than curative way should be recommended.
authors.affiliation: Equipe Microbiologie de l'Eau, Ecologie et Biologie des Interactions, Centre National de la Recherche Scientifique UMR 7267, Université de Poitiers, Poitiers, France; Service de Bactériologie et d'Hygiène hospitalière, CHU de Poitiers, Poitiers, France. Electronic address: damien.costa@univ-poitiers.fr.
authors.forename: Damien
authors.initials: D
authors.lastname: Costa
authors.affiliation: Equipe Microbiologie de l'Eau, Ecologie et Biologie des Interactions, Centre National de la Recherche Scientifique UMR 7267, Université de Poitiers, Poitiers, France; Faculté de Médecine et de Pharmacie de Poitiers, Poitiers, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Girardot
authors.affiliation: Equipe Ecologie Evolution Symbiose, Ecologie et Biologie des Interactions, Centre National de la Recherche Scientifique UMR 7267, Université de Poitiers, Poitiers, France.
authors.forename: Joanne
authors.initials: J
authors.lastname: Bertaux
authors.affiliation: Equipe Microbiologie de l'Eau, Ecologie et Biologie des Interactions, Centre National de la Recherche Scientifique UMR 7267, Université de Poitiers, Poitiers, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Verdon
authors.affiliation: Equipe Microbiologie de l'Eau, Ecologie et Biologie des Interactions, Centre National de la Recherche Scientifique UMR 7267, Université de Poitiers, Poitiers, France; Faculté de Médecine et de Pharmacie de Poitiers, Poitiers, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Imbert
mesh_terms: D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects* / Q000502:physiology; D019551:Dental Disinfectants / Q000494:pharmacology*; D004203:Disinfection; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D016846:Tubulina / Q000187:drug effects* / Q000502:physiology
chemical_list: D019551:Dental Disinfectants
keywords: Calbenium; Candida albicans; Disinfection; Model; Oxygenal 6; Pseudomonas aeruginosa; Sterispray; Vermamoeba vermiformis