Use of wet-to-moist cleansing with different irrigation solutions to reduce bacterial bioburden in chronic wounds.

Objective: The influence of different irrigation solutions, in conjunction with wet-to-moist cleansing, on the reduction of sessile, non-planktonic bacteria which colonise wounds, has not been investigated. In this study, the antibacterial effect of different irrigation solutions, during a 20-minute wet-to-moist cleansing, has been evaluated in chronic wounds. Methods: This study was designed as a prospective cohort study with 12 study arms and was conducted between June 2011 and April 2016. Patients with chronic wounds present for more than three months, irrespective of previous treatments, were recruited into this study. Quantitative wound swabs were obtained before and after a 20-minute, wet-to-moist cleansing, using different wound irrigation solutions. Sterile 0.9% saline served as a control. Results: We recruited 308 patients, of which 260 patients with 299 chronic wounds were eligible for analysis. Staphylococcus aureus was the most common recovered (25.5%) microorganism, of which 8% were meticillin-resistant Staphylococcus aureus (MRSA) strains. Although 0.9% saline supported cleansing of the wound bed, it did not significantly reduce the bacterial burden. The highest reduction of bacterial burden was achieved with an aqueous solution containing betaine, zinc and polyhexamethylene biguanide (polihexanide; In RF=3.72), followed by a 3% saline solution containing 0.2% sodium hypochlorite (In RF=3.40). The most statistically significant reduction of bacterial burden, although not the highest, was achieved with povidone-iodine (In RF=2.98; p=0.001) and an irrigation solution containing sea salt 1.2% and NaOCl 0.4% (In RF=2.51; p=0.002). Conclusion: If a reduction of bacterial burden is warranted, wound irrigation solutions containing a combination of hypochlorite/hypochlorous acid, or antiseptics such as polihexanide, octenidine or povidone-iodine, ought to be considered.