title: Sensitivity of Vermamoeba (Hartmannella) vermiformis cysts to conventional disinfectants and protease.
abstract: Vermamoeba vermiformis is a free-living amoeba (FLA) widely distributed in the environment, known to colonize hot water networks and to be the reservoir of pathogenic bacteria such as Legionella pneumophila. FLA are partly resistant to biocides, especially in their cyst form. The control of V. vermiformis in hot water networks represents an important health issue, but there are very few data on their resistance to disinfection treatments. The sensitivity of cysts of two strains of V. vermiformis to three disinfectants frequently used in hot water networks (chlorine, heat shock, peracetic acid (PAA) mixed with hydrogen peroxide (H2O2)) was investigated. In vitro, several concentrations of biocides, temperatures and exposure times according to the French regulation were tested. Cysts were fully inactivated by the following conditions: 15 mg/L of chlorine for 10 min; 60 °C for 30 min; and 0.5 g/L equivalent H2O2 of PAA mixed with H2O2 for 30 min. For the first time, the strong efficacy of subtilisin (0.625 U/mL for 24 h), a protease, to inactivate the V. vermiformis cysts has been demonstrated. It suggests that novel approaches may be efficient for disinfection processes. Finally, V. vermifomis cysts were sensitive to all the tested treatments and appeared to be more sensitive than Acanthamoeba cysts.
authors.affiliation: Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France E-mail: marie-cecile.trouilhe@cstb.fr; Université de Poitiers, CNRS UMR 7267, Laboratoire Ecologie et Biologie des Interactions, Equipe Microbiologie de l'Eau, 1 rue Georges Bonnet, BP 633, 86073 Poitiers Cedex 9, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Fouque
authors.affiliation: Université de Poitiers, CNRS UMR 7267, Laboratoire Ecologie et Biologie des Interactions, Equipe Microbiologie de l'Eau, 1 rue Georges Bonnet, BP 633, 86073 Poitiers Cedex 9, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Héchard
authors.affiliation: Faculty of Medicine, INSERM INGRES EA 7298, Department of Environment and Public Health, 9 avenue de la Forêt de Haye, BP 184, 59505 Vandœuvre-lès-Nancy Cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Hartemann
authors.affiliation: Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France E-mail: marie-cecile.trouilhe@cstb.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Humeau
authors.affiliation: Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France E-mail: marie-cecile.trouilhe@cstb.fr.
authors.forename: Marie-Cécile
authors.initials: MC
authors.lastname: Trouilhé
mesh_terms: D000818:Animals; D004202:Disinfectants / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods; D006249:Hartmannella / Q000187:drug effects*; D010447:Peptide Hydrolases / Q000494:pharmacology*; D014867:Water / Q000469:parasitology
chemical_list: D004202:Disinfectants; D014867:Water; D010447:Peptide Hydrolases