title: Risk Assessment for the Spread of Serratia marcescens Within Dental-Unit Waterline Systems Using Vermamoeba vermiformis.
abstract: Vermamoeba vermiformis is associated with the biofilm ecology of dental-unit waterlines (DUWLs). This study investigated whether V. vermiformis is able to act as a vector for potentially pathogenic bacteria and so aid their dispersal within DUWL systems. Clinical dental water was initially examined for Legionella species by inoculating it onto Legionella selective-medium plates. The molecular identity/profile of the glassy colonies obtained indicated none of these isolates were Legionella species. During this work bacterial colonies were identified as a non-pigmented Serratia marcescens. As the water was from a clinical DUWL which had been treated with Alpron™, this prompted the question as to whether S. marcescens had developed resistance to the biocide. Exposure to Alpron™ indicated that this dental biocide was effective, under laboratory conditions, against S. marcescens at up to 1 × 10(8) colony forming units/millilitre (cfu/ml). V. vermiformis was cultured for 8 weeks on cells of S. marcescens and Escherichia coli. Subsequent electron microscopy showed that V. vermiformis grew equally well on S. marcescens and E. coli (P = 0.0001). Failure to detect the presence of S. marcescens within the encysted amoebae suggests that V. vermiformis is unlikely to act as a vector supporting the growth of this newly isolated, nosocomial bacterium.
authors.affiliation: Oral & Dental Sciences Research Group, School of Medicine and Dentistry, University of Central Lancashire, Preston, PR1 2HE, England, UK, slal1@uclan.ac.uk.
authors.forename: Sham
authors.initials: S
authors.lastname: Lal
authors.forename: Sim K
authors.initials: SK
authors.lastname: Singhrao
authors.forename: Undine E M
authors.initials: UE
authors.lastname: Achilles-Day
authors.forename: L H Glyn
authors.initials: LH
authors.lastname: Morton
authors.forename: Mark
authors.initials: M
authors.lastname: Pearce
authors.forename: StJohn
authors.initials: S
authors.lastname: Crean
mesh_terms: D003770:Dental Offices; D004202:Disinfectants / Q000494:pharmacology; D060766:Drinking Water / Q000382:microbiology* / Q000469:parasitology*; D004492:Edetic Acid / Q000494:pharmacology; D016840:Lobosea / Q000166:cytology / Q000254:growth & development / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D008858:Microscopy, Phase-Contrast; D012706:Serratia marcescens / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*; D012973:Sodium Hypochlorite / Q000494:pharmacology
chemical_list: C472596:Alpron; D004202:Disinfectants; D060766:Drinking Water; D004492:Edetic Acid; D012973:Sodium Hypochlorite