Synergistic Removal of Static and Dynamic Staphylococcus aureus Biofilms by Combined Treatment with a Bacteriophage Endolysin and a Polysaccharide Depolymerase

Abstract

Staphylococcus aureus is an important pathogen and biofilm former. Biofilms cause problems in clinics and food production and are highly recalcitrant to antibiotics and sanitizers. Bacteriophage endolysins kill bacteria by degrading their cell wall and are therefore deemed promising antimicrobials and anti-biofilm agents. Depolymerases targeting polysaccharides in the extracellular matrix have been suggested as parts of a multi-enzyme approach to eradicate biofilms. The efficacy of endolysins and depolymerases against S. aureus biofilms in static models has been demonstrated. However, there is a lack of studies evaluating their activity against biofilms grown under more realistic conditions. Here, we investigated the efficacy of the endolysin LysK and the poly-N-acetylglucosamine depolymerase DA7 against staphylococcal biofilms in static and dynamic (flow cell-based) models. LysK showed activity against multiple S. aureus strains, and both LysK and DA7 removed static and dynamic biofilms from polystyrene and glass surfaces at low micromolar and nanomolar concentrations, respectively. When combined, the enzymes acted synergistically, as demonstrated by crystal violet staining of static biofilms, significantly reducing viable cell counts compared to individual enzyme treatment in the dynamic model, and confocal laser scanning microscopy. Overall, our results suggest that LysK and DA7 are potent anti-biofilm agents, alone and in combination.

Targeting Hidden Pathogens: Cell-Penetrating Enzybiotics Eradicate Intracellular Drug-Resistant Staphylococcus aureus

“…Therefore, they contribute little to combat the aggravating antibiotic resistance crisis and the associated problem of drug-tolerant and persistent S. aureus (59). PGHs, on the other hand, and phage endolysins in particular, offer the unique advantage of an active and rapid lytic mechanism, with high efficacy against antibiotic-resistant bacteria, metabolically inactive persisters, and biofilms (9,60). For these reasons, CPP-fused PGHs hold promise as novel and effective future protein therapeutics.…”

Isolation and characterization of the <em>Staphylococcus aureus</em> bacteriophage vB_SauS_SA2

“…Staphylococcus aureus is an important prevalent pathogen that can cause a variety of infectious diseases in both humans and animals through different pathways [1],[2]. The multifarious diseases caused by S. aureus include suppurative infections, pneumonia, pericarditis and meningitis in humans [3] and various local or systemic infectious diseases in animals, such as avian arthritis, bovine mastitis and septicemia [4].…”

Phages for Biofilm Removal

“…For instance, lysin LysK and depolymerase DA7 have been tested in combination against Staphylococcus aureus biofilms in static and dynamic models. These enzymes showed a synergistic behavior, significantly reducing the number of viable cells in the biofilm [83].…”