Bacteriophage Treatment before Chemical Disinfection Can Enhance Removal of Plastic-Surface-Associated Pseudomonas aeruginosa

Abstract

Opportunistic pathogens can linger on surfaces in hospital and building plumbing environments, leading to infections in at-risk populations. Further, biofilm-associated bacteria are protected from removal and inactivation protocols, such as disinfection. Bacteriophages show promise as tools to treat antibiotic resistant infections. As such, phages may also be useful in environmental applications to prevent newly acquired infections. In the current study, the potential of synergies between bacteriophage and chemical disinfection of the opportunistic pathogen Pseudomonas aeruginosa was assessed under various conditions. Specifically, surface-associated P. aeruginosa was treated with various concentrations of phages (P1 or JG004), chemical disinfectant (sodium hypochlorite or benzalkonium chloride), or combined sequential treatments under three distinct attachment models (spot inoculations, dry biofilms, and wet biofilms). Phages were very effective at removing bacteria in spot inoculation (>3.2 log 10 removal) and wet biofilms (up to 2.6 log 10 removal), while phages prevented regrowth of dry biofilms in the application time. In addition, phage treatment followed by chemical disinfection inactivated more P. aeruginosa under wet biofilm conditions better than either treatment alone. This effect was hindered when chemical disinfection was applied first, followed by phage treatment, suggesting additive benefits of combination treatments are lost when phage is applied last. Further, we confirm prior evidence of greater phage tolerance to benzalkonium chloride relative to sodium hypochlorite, informing choices for combination phage-disinfectant approaches. Overall, this paper further supports the potential of using combination phage and chemical disinfectant treatments to improve inactivation of surface-associated P. aeruginosa . Importance Phages are already utilized in the healthcare industry to treat antibiotic resistant infections, such as on implant-associated biofilms and in compassionate care cases. Phage treatment could also be a promising new tool to control pathogens in the built environment, preventing infections from occurring. This study shows that phage can be combined effectively with chemical disinfectants to improve removal of wet biofilms and bacteria spotted onto surfaces while preventing regrowth in dry biofilms. This has the potential to improve pathogen containment within the built environment and drinking water infrastructure to prevent infections of opportunistic pathogens.

Assessment of Phage-Mediated Inhibition and Removal of Multidrug-Resistant Pseudomonas aeruginosa Biofilm on Medical Implants

“…Besides using mono phages, positive results have been reported on the use of phage cocktails to prevent ET colonization 18 by this bacterium. Outside the medical scope, effective use of mono phages or phage cocktails as biocontrol agents of PA in water 37 and phage combination with disinfectants to remove plastic-surface associated PA 38 have been recently reported. These studies highlight the urgent need to investigate new strategies to prevent, control, or remove PA biofilms from surfaces.…”

Bacteriophage-based decontamination to control environmental colonization by Staphylococcus capitis in neonatal intensive care units: An in vitro proof-of-concept

“…The effect of a bacteriophage cocktail was tested on the reference strain CR01 in comparison with the disinfectant Surfanios Premium (SP) (composed of N-(3-aminopropyl)-N-dodécylpropane-1,3-diamine and chlorure de didécyldiméthylammonium) (ANIOS, Lezennes, France). Both treatments were tested on dry spots and on pre-formed biofilms using a previously published method with some modifications ( Stachler et al., 2021 ). For bacteriophage cocktails preparation, the three bacteriophages were associated by diluting each of them in equal measure in either TSB or Phosphate Buffered Saline (PBS) (Thermo Fisher Scientific, Waltham, MA, USA) to obtain cocktails at three different final concentrations (3.10 4 PFU/mL, 3.10 6 PFU/mL or 3.10 8 PFU/mL).…”

Phages against Pathogenic Bacterial Biofilms and Biofilm-Based Infections: A Review

“…Apart from the therapeutic options mentioned above, several other phage-based alternative strategies have also been reported in preventing and controlling bacterial biofilms. A current study on the potential synergistic effect of phage and chemical disinfection against the opportunistic pathogen P. aeruginosa has shown that phages can effectively combine with chemical disinfectants, such as sodium hypochlorite and benzalkonium chloride, to improve the removal of wet biofilms and bacterial spots on surfaces and prevent the regeneration of dry biofilms at the same time [91]. In addition, He et al proposed a novel AIE-phage integrated strategy, in which phage PAP is equipped with photodynamic inactivation (PDI)-active AIEgens (luminogens with aggregation-induced emission property) to form a new type of antimicrobial bioconjugate, TVP-PAP, with a nearly 100% killing efficiency against multidrug-resistant P. aeruginosa [92].…”