Negative-Pressure Wound Therapy in a Infection Model.

BACKGROUND

Negative-pressure wound therapy (NPWT) is an effective strategy for the management of contaminated wounds, including those infected by . We hypothesized that NPWT would reduce virulence factors as well as biofilm components and inhibit virulence-regulated gene expression in a model of wound infection.

METHODS

Wounds were created in anesthetized rabbits and was inoculated to the wound surface for 24 h. Wounds were treated with either NPWT or a sterile gauze dressing. Virulence factors including exotoxin A, rhamnolipid, and elastase were quantified by the enzyme-linked immunosorbent assay, orcinol, and elastin-Congo red methods, respectively. A biofilm component, eDNA, was quantified using a commercial kit. Virulence-regulated genes were determined by quantitative real-time polymerase chain reaction (RT-PCR). Biofilms were observed by staining with concanavalin A conjugated to Alexa Fluor® 647.

RESULTS

NPWT was more effective than the control treatment in reducing virulence factors and bacteria counts . A biofilm component, eDNA, was less abundant in the NPWT group. The results of the RT-PCR indicated that the expression levels of virulence-regulated genes and quorum-sensing population density-dependent systems were significantly inhibited by NPWT treatment.

CONCLUSION

NPWT reduced bacteria counts, virulence factors, and eDNA in a wound infection model . These beneficial effects are likely to be related to the reduced expression of virulence-regulated genes and the drainage induced by NPWT treatment. These findings may help clinicians to obtain a better understanding of the mechanism of NPWT for the treatment of infected wounds.