Bacteriophage Infectivity Against Pseudomonas aeruginosa in Saline Conditions

Abstract

Pseudomonas aeruginosa is a ubiquitous member of marine biofilm, and reduces thiosulfate to produce toxic hydrogen sulfide gas. In this study, lytic bacteriophages were isolated and applied to inhibit the growth of P. aeruginosa in planktonic mode at different temperature, pH, and salinity. Bacteriophages showed optimal infectivity at a multiplicity of infection of 10 in saline conditions, and demonstrated lytic abilities over all tested temperature (25, 30, 37, and 45°C) and pH 6–9. Planktonic P. aeruginosa exhibited significantly longer lag phase and lower specific growth rates upon exposure to bacteriophages. Bacteriophages were subsequently applied to P. aeruginosa-enriched biofilm and were determined to lower the relative abundance of Pseudomonas-related taxa from 0.17 to 5.58% in controls to 0.01–0.61% in treated microbial communities. The relative abundance of Alphaproteobacteria, Pseudoalteromonas, and Planococcaceae decreased, possibly due to the phage-induced disruption of the biofilm matrix. Lastly, when applied to mitigate biofouling of ultrafiltration membranes, bacteriophages were determined to reduce the transmembrane pressure increase by 18% when utilized alone, and by 49% when used in combination with citric acid. The combined treatment was more effective compared with the citric acid treatment alone, which reported ca. 30% transmembrane pressure reduction. Collectively, the findings demonstrated that bacteriophages can be used as a biocidal agent to mitigate undesirable P. aeruginosa-associated problems in seawater applications.

UV and bacteriophages as a chemical-free approach for cleaning membranes from anaerobic bioreactors

“…Acinetobacter genus, namely A. modestus, A junii and A. seohaensis were isolated from the influent of the KAUST wastewater treatment plant as described before (21) and propagated by the double layer method (48). A detailed description of bacteriophages isolation can be found in supporting information, section "Bacteriophages isolation".…”

“…Besides infecting their intended bacterial host, bacteriophages can also induce the release of enzymes that degrade the EPS biofilm matrix, in turn, increasing biofilm susceptibility to biocides (20). Moreover, bacteriophages are able to infect bacteria over a broad range of pH, salinity and temperature (21). For these reasons, bacteriophages were also applied as a biological-based approach to reduce membrane biofouling (22), albeit mainly demonstrated against single-species biofilms (23,24).…”

“…For these reasons, bacteriophages were also applied as a biological-based approach to reduce membrane biofouling (22), albeit mainly demonstrated against single-species biofilms (23,24). However, the use of bacteriophages alone does not lead to adequate efficacy in terms of biofouling reduction (21) and their effectiveness against a complex biofilm has not been demonstrated. Instead, bacteriophages were applied in combination with chemicals to enhance their effect on membrane biofilm (21,25).…”

“…However, the use of bacteriophages alone does not lead to adequate efficacy in terms of biofouling reduction (21) and their effectiveness against a complex biofilm has not been demonstrated. Instead, bacteriophages were applied in combination with chemicals to enhance their effect on membrane biofilm (21,25). This counteracts the use of biological-based approaches to minimize chemical usage.…”

Understanding the antifouling mechanisms related to copper oxide and zinc oxide nanoparticles in anaerobic membrane bioreactors

“…quorum quenching and phage-based decomposition). [10][11][12] In particular, coating heavy metal nanoparticles on the surface of membranes demonstrated promising results. An earlier study demonstrated that polysulfone membranes impregnated with silver (Ag) nanoparticles showed not only high antibacterial properties but also improved biofouling resistance.…”