title: The efficacy of chlorination and filtration in the control and eradication of Legionella from dental chair water systems.
abstract: The apparent failure of hyperchlorination and continuous dosing with chlorine to eliminate legionellae from a dental teaching hospital water supply prompted a prospective study to evaluate charcoal filters as a means of decontamination. Legionella pneumophila serogroup 10 and L. bozemanii serogroup 2 were isolated from dental units yielding 10(1)-10(3) colony forming units (cfu) ml-1 with total bacterial counts in the range 10(2)-greater than 10(4) cfu ml-1. After chair-side installation of charcoal filters bacterial contamination of the dental unit water was prevented and legionellae were initially not detected, but after 7 days the total count returned to pre-filtration levels of greater than 10(4) cfu ml-1; L. pneumophila serogroup 10 was eliminated but L. bozemanii serogroup 2 persisted. These results suggest that neither chlorination nor charcoal filtration deal adequately with the potential hazard of Legionella spp. in dental water.
authors.affiliation: Department of Oral Microbiology, King's College School of Medicine and Dentistry, London.
authors.forename: C L
authors.initials: CL
authors.lastname: Pankhurst
authors.forename: J N
authors.initials: JN
authors.lastname: Philpott-Howard
authors.forename: J H
authors.initials: JH
authors.lastname: Hewitt
authors.forename: M W
authors.initials: MW
authors.lastname: Casewell
mesh_terms: D002606:Charcoal; D002713:Chlorine; D003748:Dental Equipment; D004203:Disinfection / Q000379:methods*; D005374:Filtration; D007875:Legionella / Q000187:drug effects / Q000302:isolation & purification*; D011446:Prospective Studies; D013242:Sterilization / Q000379:methods*; D014881:Water Supply
chemical_list: D002606:Charcoal; D002713:Chlorine