Quantifying bacterial bioburden during negative pressure wound therapy: does the wound VAC enhance bacterial clearance?

The bacterial colonization of a wound is a recognized detrimental factor in the multifactorial process of wound healing. The harmful effects on wound healing are recognized to correspond to a level of > 10(5) colonies of bacteria per gram of tissue. Negative pressure wound therapy has become an accepted treatment modality for acute and chronic wounds with accelerated healing rates observed. It has been previously reported that this therapy enhances bacterial clearance, which may account for the wound healing effects noted. We retrospectively reviewed 25 patients' charts undergoing Wound VAC (Vacuum Assisted Closure Device; KCI International, San Antonio, TX) therapy with serial quantitative cultures and found that there is not a consistent effect of bacterial clearance with the Wound VAC. Furthermore, bacterial colonization increased significantly with Wound VAC therapy and remained in a range of 10(4)-10(6). Despite this finding, the beneficial effects of this treatment modality on wound healing were noted in most cases.