A randomized clinical trial of silver hydrofiber dressing versus collagenase ointment for venous ulcer: analysis of biofilm-producing bacteria and bacterial clonality

Abstract

BACKGROUND: Superficial infection in venous ulcers (VU) hinders healing. OBJECTIVE: To evaluate the action of hydrofiber dressing with silver (HAg) compared to collagenase ointment (Col) in VU. METHODS: Randomized controlled clinical trial in which patients with VU with superficial infection were randomized to the intervention (HAg) or comparison (Col) group. After 30 days (T30), the primary outcomes evaluated were: rate of ulcers without signs of superficial infection, decrease in bacterial load, presence of biofilm-producing bacteria, and bacterial clonality. RESULTS: Thirty-four patients (56 ulcers) were included ‒ 18 patients (28 ulcers) in the HAg group and 16 (28 ulcers) in the Col group. There was a reduction in ulcers with superficial infection in both groups over time but with no differences (p = 0.422). There was no decrease in total bacterial load over time (p = 0.054) or between the groups (p = 0.113). There was a reduction in the rate of ulcers with biofilm-forming bacteria over time (p = 0.047) but no differences between groups (p = 0.558). Regarding the clonality of Staphylococcus aureus, 92.8% of ulcers in the HAg group and 85% in the Col group, the clones identified at T0 were the same at T30 (p = 0.553). There was no change in the identity of Pseudomonas aeruginosa in any ulcer in either group. STUDY LIMITATIONS: Short follow-up time. CONCLUSION: Both interventions improved the clinical and some microbiologic characteristics, but there was no difference between both interventions. In addition, most ulcers showed indistinguishable genetic profiles of S. aureus and P. aeruginosa between T0 and T30, with no difference between the groups.