Hydrofiber with silver versus collagenase for treatment of critical colonization of venous ulcers: randomized clinical trial

Background: Venous ulcers (VU) are colonized by several bacteria, some of which have a high biofilm production capacity and can hinder healing. Objectives: To evaluate the action of the Hydrofiber with silver dressing versus collagenase against critical colonization (superficial infection) by Staphylococcus aureus, Pseudomonas aeruginosa and Staphylococcus epidermidis and the formation of biofilm by these bacteria in patients with VU. Methods: Randomized, controlled clinical trial with VU with clinical signs of critical colonization. Patients using topical or systemic antimicrobials were excluded. After superficial debridement, participants were randomized into two groups - Hydrofiber with silver (HAg) and Collagenase (Col). Pre-debridement, a swab in an area of 1cm2 was performed for identification of S aureus, S. epidermidis and P aeruginosa and determination of the number of CFU/cm2. The capacity to produce biofilm on a polystyrene microplate was evaluated. Outcomes were evaluated after 30 days (T30): primary- ulcer rate with decreased bacterial load, rate of ulcer with biofilm-producing bacteria. Secondary outcomes were: clinical improvement of VU using the PUSH scale, and decreased ulcerated area. Results: 34 patients were included, totalizing 56 VU. Eighteen participants with 28 VU were randomized to the HAg group and 16 participants with 28 VU to the Col group. At T30, 8 of 15 ulcers (53,3%) ulcers had decreased bacterial load of Staphylococcus aureus, Pseudomonas aeruginosa and Staphylococcus epidermidis in the Col group and 10 of 20 (50%) ulcers in the HAg group, RR 1.04 (95% CI 0.55-1.90), p=0.91. In the Col group there were 9 (32.1%) ulcers with biofilm-producing bacteria and 6 (21.4%) in the HAg group, RR 1.25 (CI 95% 0.76 -2.2), p=0.39. The median of the PUSH score at T30 in the Col group was 13 (P25% 9.8 – p75% 15.0) and 14 in the HAg group (P25% 9.8 -P75% 15.0)(p >0.05). The decrease in the ulcerated area occurred in 16 ulcers (69.6%) in the Col group and 20 ulcers (87%) in the HAg group, RR 1.25 [CI 0.91-1.71] p=0.15). Conclusion: There was no difference in clinical and microbiological outcomes between the collagenase and Hydrofiber with silver group evaluated 30 days after the interventions.