Comparison of antimicrobial activity between Manuka and Silver-based dressings used for treating infected venous ulcers

AIM: This study compared the antimicrobial activity of Manuka dressings with silver-based ones for treating infected venous ulcers. It also assessed the possible bacterial resistance to the two treatments. METHODS: This study was an open longitudinal non-randomized clinical trial that evaluated the antimicrobial efficacy of Manuka and silver in terms of healing times for treating infected venous ulcers. The study population consisted of people with infected venous ulcers. The recruitment occurred according to inclusion and exclusion criteria, and treatment was chosen alternately by the professional. The evaluation of the wound occurred at T0 (enlistment), T1 (15 days from enlistment), and T2 (30 days). The tool used for monitoring at different times was a form created by experts. RESULTS: The sample was 50 infected venous ulcers: 25 were treated with silver dressing and 25 were treated with Manuka. At T2, 13.6% of venous ulcers treated with Manuka (p-value 0.001; P -0.641) and 64% of venous ulcers treated with silver (p-value 0.000; P -0.900) were healed. However, after the swab test at T1, 84% of Manuka-treated ulcers were no longer infected, whereas 44% of silver-treated ulcers were still infected with microorganisms such as staphylococcus aureus and pseudomonas aeruginosa. Hence, a possible bacterial resistance to silver. CONCLUSIONS: The results showed that the infected venous ulcer treated with Manuka was more effective than the silver-based one, although after a longer time. Additionally, Staphylococcus aureus and Pseudomonas aeruginosa may exhibit resistance to silver. To confirm these data, it would be helpful to conduct longitudinal RCTs.