Negative pressure wound therapy reduces pseudomonas wound contamination more than Staphylococcus aureus

The purpose of this study is to determine if negative pressure wound therapy (NPWT) treatment results in fewer bacteria than wet-to-dry (WTD) dressings in a contaminated open fracture wound model.

For Study 1, complex wounds were created on the proximal left leg of goats. The wounds were inoculated with Pseudomonas aeruginosa. The wounds were débrided and irrigated 6 hours after inoculation. The first group received WTD dressing changes twice daily; the second and third groups received NPWT using systems from two different companies. All three groups received repeat débridements every 48 hours for 6 days. Bacteria quantification was performed both immediately before and after each débridement. For Study 2, the only changes were that Staphylococcus aureus was used and only one NPWT group was included.

In Study 1, there were significantly fewer Pseudomonas in both NPWT groups at all imaging sessions after the initial débridement and irrigation. At the 6-day time point, the wounds in the NPWT groups were 43 +/- 14% and 68 +/- 6% of the baseline amount, respectively. The WTD groups were 464 +/- 102% of the baseline amount. In Study 2, NPWT did not reduce the S. aureus contamination within the wound. At the 6-day time point, the wounds in the NPWT and WTD groups contained 115 +/- 19% and 192 +/- 52% of the baseline values, respectively.

NPWT showed a significant and sustained decrease in the Pseudomonas levels compared with WTD dressings at all time points. This beneficial effect was seen not seen in S. aureus.