Enzymatic degradation of in vitro Staphylococcus aureus biofilms supplemented with human plasma

Abstract

Enzymatic debridement is a therapeutic strategy used clinically to remove necrotic tissue from wounds. Some of the enzymes utilized for debridement have been tested against bacterial pathogens, but the effectiveness of these agents in dispersing clinically relevant biofilms has not been fully characterized. Here, we developed an in vitro Staphylococcus aureus biofilm model that mimics wound-like conditions and employed this model to investigate the antibiofilm activity of four enzymatic compounds. Human plasma at concentrations of 0%–50% was supplemented into growth media and used to evaluate biofilm biomass accumulation over 24 hours and 48 hours in one methicillin-sensitive and five methicillin-resistant strains of S. aureus. Supplementation of media with 10% human plasma resulted in the most robust biofilms in all six strains. The enzymes α-amylase, bromelain, lysostaphin, and papain were then tested against S. aureus biofilms cultured in 10% human plasma. Quantification of biofilms after 2 hours and 24 hours of treatment using the crystal violet assay revealed that lysostaphin decreased biomass by up to 76%, whereas α-amylase, bromelain, and papain reduced biomass by up to 97%, 98%, and 98%, respectively. Scanning electron microscopy confirmed that the dispersal agents detached the biofilm exopolysaccharide matrix and bacteria from the growth surface. Lysostaphin caused less visible dispersal of the biofilms, but unlike the other enzymes, induced morphological changes indicative of bacterial cell damage. Overall, our results indicate that use of enzymes may be an effective means of eradicating biofilms and a promising strategy to improve treatment of multidrug-resistant bacterial infections.

Glycoside Hydrolases Degrade Polymicrobial Bacterial Biofilms in Wounds

“…In this way, clinicians would be able to administer the enzymes to any patient presenting with a biofilm infection, regardless of the causative microorganisms, and have a reasonable expectation that the therapy will be effective. ␣-Amylase and cellulase are two inexpensive, commercially available GHs that target common linkages found in the EPS made by many different species of bacteria, and multiple studies have shown that they can inhibit and disrupt the preformed in vitro biofilms of a variety of bacterial species (22)(23)(24)(25)(26).…”

“…It has been shown that cellulase inhibits biofilm growth by Burkholderia cepacia and Pseudomonas aeruginosa on various abiotic surfaces commonly used in medical devices (22,23). Similarly, ␣-amylase, a GH that acts by cleaving the ␣-1,4 straight-chain linkage, has been previously shown to both inhibit biofilm formation and disrupt preformed biofilms of Vibrio cholerae, Staphylococcus aureus and P. aeruginosa in vitro (24)(25)(26). In this study, we aimed to hydrolyze the polysaccharides produced by S. aureus and P. aeruginosa in dual-species polymicrobial biofilms by targeting a pair of highly conserved glycosidic linkages.…”

Current therapies in treatment and prevention of fracture wound biofilms: why a multifaceted approach is essential for resolving persistent infections

“…As of 2008, the FDA no longer recommends papain/urea for use. However, papain itself has been shown to have anti-biofilm properties in vitro , suggesting it possesses activity against bacterial proteins 136 . In fact, papain was shown to directly degrade the Actinomyces fimbrial proteins FimA and FimP in a dental plaque model 137 .…”

Ultrasound‐mediated therapies for the treatment of biofilms in chronic wounds: a review of present knowledge

“…The presence of persister cells allows the regeneration of the biofilm within the wound bed, which means that debridement is by no means a complete or permanent solution (Lebeaux et al, 2014). The efficacy of debridement can be improved by chemical and biological adjuvants, such as hydrogen peroxide and enzymes respectively (Watters et al, 2016). By causing the EPS matrix of the biofilm to degrade, and thus removing its principal means of protection and nutrition, the rate of wound healing is significantly increased (Kim et al, 2018).…”