Growth and Identification of Bacteria inN-Halamine Dental Unit Waterline Tubing Using an Ultrapure Water Source

Abstract

This study examined bacterial growth and type on biofilm-controlling dental unit waterline (DUWL) tubing (T) and control manufacturer's tubing (C) in a laboratory DUWL model using ultrapure source water that was cycled through the lines. Sections of tubing lines were detached and examined for biofilm growth using SEM imaging at six sampling periods. Bacteria from inside surfaces of T and C, source unit, and reservoir were cultured and enumerated. At six months, organisms were molecularly identified from the alignment matches obtained from the top three BLAST searches for the 16S region. There was a 1–3 log increase in organism growth in a clean, nonsterile reservoir within an hour. Biofilm was established on the inside surfaces of C within three weeks, but not on T. Proteobacteria, and Sphingomonas spp. were identified in the source reservoir and C line, and a variation of the genera was found in T line.

Chemical Insights into Antibacterial N-Halamines

“…Although the mechanical properties of the tubing were not significantly affected by the N-halamine grafting, evaluation with P. aeruginosa in a continuous bacterial flow model showed that the inner surfaces of the grafted PU tubing completely prevented the formation of bacterial biofilm for at least 3 to 4 weeks. Porteous et al 393 subsequently examined bacterial growth and type on biofilm-controlling Nhalamine-grafted DUWL tubing and on controlled manufacturer's tubing in a laboratory DUWL model to check the modified tubing's efficacy. After 3 weeks, biofilm was still absent from that tubing, whereas it was present on the inner surfaces of the controlled tubing, suggesting that the former had prevented biofilm formation.…”

“…To reduce threats to human health, antimicrobial agents can often be used to combat and eradicate pathogens in these contexts . Unlike other antibacterial agents, N -halamine-based materials have garnered a great deal of interest for use in medical and healthcare products owing to the unique antimicrobial functions related to halogens and/or halogen analogues. − Luo et al used a surface grafting approach to introduce acyclic N -halamines onto the inner surfaces of continuous, small-bore, polyurethane (PU) dental unit waterline (DUWL) tubing (Figure ). Experimentally, methacrylamide (MMA) was grafted onto the tubing’s inner walls by a polymerization approach in which dicumyl peroxide (DCP) was used as a free-radical initiator.…”

Minimising microbial contamination in dental unit water systems and microbial control in dental hospitals

“…However, levels of bacteria in DUWL output water remained unacceptably high in output water from DUWLs made from both materials. Other studies investigated polyurethane DUWL tubing coated with N -halamine using laboratory model systems and showed that the coated tubing resisted biofi lm formation (Porteous et al ., 2011 ). However, this latter system has yet to be tested with working dental units.…”