Antibiofilm Efficacy of DispersinB Wound Spray Used in Combination with a Silver Wound Dressing

Chronic wounds including diabetic foot ulcers, pressure ulcers, and venous leg ulcers are a worldwide health problem. As the traditional methods of treatment have proven ineffective against chronic wounds involving biofilms, there is an unmet clinical need for developing products with an antibiofilm component that inhibits and/or disrupts biofilms and thus make the biofilm-embedded bacteria more susceptible to antimicrobial therapy. We developed a DispersinB® antibiofilm enzyme-based wound spray for treating chronic wounds in conjunction with an antimicrobial. Under in vitro conditions, the DispersinB® and Acticoat™ combination performed significantly better ( P < 0.05) than Acticoat™ alone, indicating the synergy between the two compounds because of DispersinB® enhancing the antimicrobial activity of Acticoat™. Furthermore, DispersinB® wound spray enhanced the antimicrobial activity of Acticoat™ in a chronic wound mouse model of methicillin-resistant Staphylococcus aureus (MRSA) infection. Thus, this novel combination of DispersinB® and Acticoat™, an antimicrobial dressing, prompts clinical evaluation for potential applications in biofilm-based chronic wound management

Noneluting Enzymatic Antibiofilm Coatings

We developed a highly efficient, biocompatible surface coating that disperses bacterial biofilms through enzymatic cleavage of the extracellular biofilm matrix. The coating was fabricated by binding the naturally existing enzyme dispersin B (DspB) to surface-attached polymer matrices constructed via a layer-by-layer (LbL) deposition technique. LbL matrices were assembled through electrostatic interactions of poly­(allylamine hydrochloride) (PAH) and poly­(methacrylic acid) (PMAA), followed by chemical cross-linking with glutaraldehyde and pH-triggered removal of PMAA, producing a stable PAH hydrogel matrix used for DspB loading. The amount of DspB loaded increased linearly with the number of PAH layers in surface hydrogels. DspB was retained within these coatings in the pH range from 4 to 7.5. DspB-loaded coatings inhibited biofilm formation by two clinical strains of <i>Staphylococcus epidermidis</i>. Biofilm inhibition was ≥98% compared to mock-loaded coatings as determined by CFU enumeration. In addition, DspB-loaded coatings did not inhibit attachment or growth of cultured human osteoblast cells. We suggest that the use of DspB-loaded multilayer coatings presents a promising method for creating biocompatible surfaces with high antibiofilm efficiency, especially when combined with conventional antimicrobial treatment of dispersed bacteria

Characterization of the Poly-β-1,6-N-Acetylglucosamine Polysaccharide Component of Burkholderia Biofilms ▿

We demonstrated the production of poly-β-1,6-N-acetylglucosamine (PNAG) polysaccharide in the biofilms of Burkholderia multivorans, Burkholderia vietnamiensis, Burkholderia ambifaria, Burkholderia cepacia, and Burkholderia cenocepacia using an immunoblot assay for PNAG. These results were confirmed by further studies, which showed that the PNAG hydrolase, dispersin B, eliminated immunoreactivity of extracts from the species that were tested (B. cenocepacia and B. multivorans). Dispersin B also inhibited biofilm formation and dispersed preformed biofilms of Burkholderia species. These results imply a role for PNAG in the maintenance of Burkholderia biofilm integrity. While PNAG was present in biofilms of all of the wild-type test organisms, a ΔpgaBC mutant of B. multivorans (Mu5) produced no detectable PNAG, indicating that these genes are needed for Burkholderia PNAG formation. Furthermore, restoration of PNAG production in PNAG negative E. coli TRXWMGΔC (ΔpgaC) by complementation with B. multivorans pgaBCD confirmed the involvement of these genes in Burkholderia PNAG production. While the confocal scanning laser microscopy of untreated wild-type B. multivorans showed thick, multilayered biofilm, Mu5 and dispersin B-treated wild-type biofilms were thin, poorly developed, and disrupted, confirming the involvement of PNAG in B. multivorans biofilm formation. Thus, PNAG appears to be an important component of Burkholderia biofilms, potentially contributing to its resistance to multiple antibiotics and persistence during chronic infections, including cystic fibrosis-associated infection