Chlorine-based DUWL disinfectant leads to a different microbial composition of water derived biofilms compared to H₂O₂-based chemical disinfectants in vitro

Abstract

Background Biofilm formation in dental unit waterlines (DUWL) may lead to health risks for dental staff and patients. Therefore, dental unit waterlines need to be disinfected, for instance by using chemical disinfectants. However, the application of chemical disinfectants may lead to the selection of specific microorganisms. Therefore, the aim of our study was to assess the microbial composition of water-derived biofilms, after a continuous exposure to maintenance doses of commercially available chemical disinfectants, in vitro. Methods The AAA-model was used to grow water derived biofilms. The biofilms were subjected to the maintenance dose of each disinfectant. To determine the microbial composition, the V4 hypervariable region of the 16S rRNA gene was sequenced. The sequences were clustered in operational taxonomic units (OTUs). Results The bacterial composition of biofilms in all treatment groups differed significantly (PERMANOVA F = 4.441, p = 0.001). Pairwise comparisons revealed Anoxyl treated biofilms were significantly different from all groups (p = 0.0001). In the Anoxyl-treated biofilms, the relative abundance of Comamonadaceae and Sphingopyxis was high compared to the Dentosept, Green and Clean and Oxygenal groups. Conclusion We concluded that exposure to low doses of the chlorine-based chemical disinfectant Anoxyl led to a substantially different composition of water derived biofilms compared to biofilms exposed to H2O2-based chemical disinfectants.

Electrolysed oxidising water as a multi‐purpose biocide in dental healthcare—A scoping review

“…Suspension and biofilm assays report efficacy as a reduction in colony forming units (cfu), non‐detectable counts, percentage killing and growth inhibition. Antibiofilm assays also report efficacy as changes to the biofilm cover (structural observations), 61,70,75,77,78,89,91,101,102,109–111 gene expression (RT‐qPCR) 79 and biofilm composition (16S rRNA gene sequencing) 92 . Significant microbicidal activity is reported in suspension assays either with fixed contact times or time‐kill assays against bacterial and fungal type strains, and clinical isolates 9,50,57,58,61–70,72–85,104,112 .…”

“…Liquid growth/viability assays were performed either as stand-alone procedures or prior to anti-biofilm activity measurements (30 reports 9,50,57,58, ) and as a comparative method in one 86 of the four reports that investigated EOW effectiveness by agar diffusion assays. 66,[86][87][88] In vitro adherence and anti-biofilm assays (36 reports) were performed using laboratory biofilm models (11 reports, 70,[73][74][75][77][78][79][89][90][91][92] ), extracted human teeth (14 reports 90,91,[93][94][95][96][97][98][99][100][101][102][103][104] ), bovine teeth (1 report 105 ) and biomaterial substrates (10 reports 24,61,83,[106][107][108][109][110][111][112] ).…”

“…85 Of the reports included in this review, two in vitro studies investigated the antibiofilm efficacy of EOW in DUWLs under simulated conditions. 89,92 Anti-adherence and antibiofilm efficacy has been studied with substrates such as denture resin (lined or unlined), 106,108,111 hydrocolloid impressions, 24,107 gypsum, 107 titanium (Ti) 107 and modified and unmodified Ti-alloys. 61,83,109,110 For biofilms formed on dental materials, studies predominantly investigated the effect of EOW immersion time; combined with sonication in two reports.…”

Disinfection methods of dental unit waterlines contamination: a systematic review

“…The trend of bacterial recolonization has also been found when alkaline peroxide products are used [58]. Different chemical disinfectants might lead to selection of specific microorganisms [59]. Changing the disinfectant regularly might avoid decontamination failure caused by the resistance of certain strains of microbes to the disinfectant.…”

The impact of COVID-19 on dental research in educational settings: What are the opportunities?

“…[ 21 ] Other clinical aspects relevant to protection against SARS-CoV-2 might also create opportunities in various areas including, but not limited to[ 17 22 ] infection control and risk strategies; aerosol-generating procedures and instruments;[ 17 ] antiviral mouthwashes and oral microbiology;[ 23 ] medical waste disposal; dental environment disinfection; dental unit water lines; and high-volume aspirators. [ 24 ]…”