Nitric oxide-mediated dispersal in single- and multi-species biofilms of clinically and industrially relevant microorganisms.
Bottom Line: Nitric oxide-induced dispersal was observed in all biofilms assessed, and the average reduction of total biofilm surface was 63%.Moreover, biofilms exposed to low doses of NO were more susceptible to antimicrobial treatments than untreated biofilms.For example, the efficacy of conventional chlorine treatments at removing multi-species biofilms from water systems was increased by 20-fold in biofilms treated with NO compared with untreated biofilms.
Affiliation: School of Biotechnology and Biomolecular Sciences and Centre for Marine Bio-Innovation, University of New South Wales, Sydney, NSW 2052, Australia.Show MeSH
Related in: MedlinePlus
Mentions: Recycled and potable water distribution. To study the effect of NO on multi‐species biofilms formed in recycled water distribution systems, an annular reactor (AR) containing unplasticized polyvinyl chloride (uPVC) coupons was connected to a recycled water network for 3 months. After this time, biofilms were sampled and treated in the laboratory. The data demonstrate that SNP treatment was effective at removing multi‐species biofilms as revealed with both microscopy and viability analyses by performing heterotrophic cfu counts of biofilm bacteria (Fig. 3). The most efficient concentration of SNP was 500 nM, which induced dispersal of 47 ± 3% of the biofilm compared with the untreated controls, as revealed by cfu measurements of biofilm bacteria (Fig. 3B). As seen on the microscopy images, control biofilms established from recycled water distribution system harbour mature microcolonies that contain both living and dead cells. After SNP treatments, the size of biofilm aggregates (microcolonies) on the surface was considerably reduced, indicative of dispersal events (Fig. 3A). In addition, biofilms treated with SNP displayed increased number of cells (cfu) in their effluent runoff (data not shown). Furthermore, the ratios of cfu counts to biofilm surface coverage were calculated for each treatment and normalized to the control experiments. The ratios did not vary significantly: 1.0, 0.9 and 0.9 for untreated, 100 nM SNP and 500 nM SNP respectively. These data indicate that SNP treatment effectively induced the removal of viable cells from the surface.
Affiliation: School of Biotechnology and Biomolecular Sciences and Centre for Marine Bio-Innovation, University of New South Wales, Sydney, NSW 2052, Australia.