title: Chlorine disinfection of atypical mycobacteria isolated from a water distribution system.
abstract: We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C.t value (product of the disinfectant concentration and contact time) of 60 mg.min.liter(-1), frequently used in water treatment lines, chlorine disinfection inactivates over 4 log units of M. gordonae and 1.5 log units of M. fortuitum or M. chelonae. C.t values determined under similar conditions show that even the most susceptible species, M. aurum and M. gordonae, are 100 and 330 times more resistant to chlorine than Escherichia coli. We also investigated the effects of different parameters (medium, pH, and temperature) on chlorine disinfection in a chlorine-resistant M. gordonae model. Our experimental results follow the Arrhenius equation, allowing the inactivation rate to be predicted at different temperatures. Our results show that M. gordonae is more resistant to chlorine in low-nutrient media, such as those encountered in water, and that an increase in temperature (from 4 degrees C to 25 degrees C) and a decrease in pH result in better inactivation.
authors.affiliation: Laboratoire de Référence des Mycobactéries, Institut Pasteur, 25-28 Rue du Docteur Roux, 75724 Paris Cedex 15, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Le Dantec
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Duguet
authors.forename: Antoine
authors.initials: A
authors.lastname: Montiel
authors.forename: Nadine
authors.initials: N
authors.lastname: Dumoutier
authors.forename: Sylvie
authors.initials: S
authors.lastname: Dubrou
authors.forename: Véronique
authors.initials: V
authors.lastname: Vincent
mesh_terms: D002713:Chlorine / Q000494:pharmacology*; D003470:Culture Media; D004203:Disinfection / Q000379:methods; D024881:Drug Resistance, Bacterial; D006859:Hydrogen; D006863:Hydrogen-Ion Concentration; D009170:Nontuberculous Mycobacteria / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification*; D013696:Temperature; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D003470:Culture Media; D002713:Chlorine; D006859:Hydrogen