Development of a High-Throughput ex-Vivo Burn Wound Model Using Porcine Skin, and Its Application to Evaluate New Approaches to Control Wound Infection

Abstract

Biofilm formation in wounds is considered a major barrier to successful treatment, and has been associated with the transition of wounds to a chronic non-healing state. Here, we present a novel laboratory model of wound biofilm formation using ex-vivo porcine skin and a custom burn wound array device. The model supports high-throughput studies of biofilm formation and is compatible with a range of established methods for monitoring bacterial growth, biofilm formation, and gene expression. We demonstrate the use of this model by evaluating the potential for bacteriophage to control biofilm formation by Staphylococcus aureus, and for population density dependant expression of S. aureus virulence factors (regulated by the Accessory Gene Regulator, agr) to signal clinically relevant wound infection. Enumeration of colony forming units and metabolic activity using the XTT assay, confirmed growth of bacteria in wounds and showed a significant reduction in viable cells after phage treatment. Confocal laser scanning microscopy confirmed the growth of biofilms in wounds, and showed phage treatment could significantly reduce the formation of these communities. Evaluation of agr activity by qRT-PCR showed an increase in activity during growth in wound models for most strains. Activation of a prototype infection-responsive dressing designed to provide a visual signal of wound infection, was related to increased agr activity. In all assays, excellent reproducibility was observed between replicates using this model.

In Vitro Evaluation of a Phage Cocktail Controlling Infections with Escherichia coli

“…In addition, we showed that the six-phage preparation can efficiently prevent the formation of a biofilm produced by E28 in vitro and significantly reduce an existing biofilm as reported by others [ 84 , 85 , 86 , 87 ]. Biofilms are a problem especially in the pipe systems of drinking troughs, as they are difficult to eliminate by disinfectants or cleaning [ 88 ].…”

Bioengineered Platforms for Chronic Wound Infection Studies: How Can We Make Them More Human-Relevant?

“…Further, the porcine immune system is highly similar to the human immune system, making it well-suited to study host-microbial interactions (Ganesh et al, 2015;Jensen et al, 2017). Alves, D. R. et al (2018) employed the use of an ex vivo porcine skin model as a substrate to study S. aureus biofilm formation and virulence gene expression in thermally induced wounds. In this model, a burn wound array device (BWAD) is used to create partial-thickness thermal injuries, following which the skin is excised and employed as a substrate for microbial inoculation.…”

Bacteriophages for Chronic Wound Treatment: From Traditional to Novel Delivery Systems

“…In another work, another ex vivo porcine skin model of wound infection was used for monitoring bacterial growth, biofilm formation, and gene expression [123]. This model tested phage control of S. aureus biofilm formation and the population density-dependent regulation of virulence gene expression during S. aureus growth.…”