Objective: To investigate the effect of topical negative pressure, delivered using Vacuum Assisted Closure (VAC, KCI), on the microbiology of chronic, non-infected venous leg ulcers (VLUs).
Method: Patients receiving compression therapy for a chronic VLU were recruited into this prospective pilot study. The ulcer was swabbed and VAC was applied at 125mmHg continuous sub-atmospheric pressure on day 1 for six days. Standard methods for bacteriological sampling and measuring the wound surface area were applied at baseline and at the VAC dressing changes on days 3 and 6. Log median colony forming units (CFUs) per cm2 were used for statistical analyses. The bacterial species were identified.
Results: Seven patients were recruited into and completed the study. The median log10 CFU/cm2 on days 1, 3 and 6 were 3.5, 4.7 and 5.1 respectively. There was a significant increase in bacterial colonisation between days 1 and 6 (p<0.02). No change was observed in the identified microbiological species during therapy with VAC.
Conclusion: This pilot study suggests that VAC therapy increases absolute numbers of bacteria colonising non-infected leg ulcers.
Declaration of interest: KCI supplied the VAC equipment and ARANZ the SilhouetteMobile, but both had no other influence on the study.