Developing an ecologically relevant heterogeneous biofilm model for dental-unit waterlines

• Published in: Biofouling (Chur, Switzerland) Switzerland), 2017-01, Vol.33 (1), p.75-87
• Main Authors: Lal, Sham, Pearce, Mark, Achilles-Day, Undine E. M., Day, John G., Morton, L. H. Glyn, Crean, St. John, Singhrao, Sim K.
• Format: Article
• Language: English
• Subjects: Amoeba; Bacteria; Biocides; Biodiversity; Biofilm; Biofilms; Biofilms - growth & development; Biological diversity; Colony Count, Microbial; Contamination; Dental Equipment - microbiology; Dental materials; Disinfectants - pharmacology; Ecological monitoring; Ecology; Environmental monitoring; Equipment Contamination - prevention & control; Fungi; Fungi - drug effects; Fungi - isolation & purification; Klebsiella - drug effects; Klebsiella - isolation & purification; Legionella pneumophila; Legionella pneumophila - drug effects; Legionella pneumophila - isolation & purification; Legionnaires' disease bacterium; Microbial Consortia; Microorganisms; Models, Biological; Opportunist infection; Pathogens; Pseudomonas - drug effects; Pseudomonas - isolation & purification; Silver; Silver base alloys; Similarity; simulated waterline system; Taxa; Tubing; Water Microbiology - standards
• ISSN: 0892-7014; 1029-2454
• DOI: 10.1080/08927014.2016.1260710

This study monitored the biodiversity of microbes cultured from a heterogeneous biofilm which had formed on the lumen of a section of dental waterline tubing over a period of 910 days. By day 2 bacterial counts on the outlet-water showed that contamination of the system had occurred. After 14 days, a biofilm comparable to that of clinical waterlines, consisting of bacteria, fungi and amoebae had formed. This showed that the proprietary silver coating applied to the luminal surface of the commercial waterline tubing failed to prevent biofilm formation. Molecular barcoding of isolated culturable microorganisms showed some degree of the diversity of taxa in the biofilm, including the opportunistic pathogen Legionella pneumophila. Whilst the system used for isolation and identification of contaminating microorganisms may underestimate the diversity of organisms in the biofilm, their similarity to those found in the clinical environment makes this a promising test-bed for future biocide testing.