Bacterial colonization and healing of venous leg ulcers

The aim of the study was to evaluate a possible influence of selected bacterial species on healing of venous leg ulcers. Fifty-nine patients with venous leg ulcers were followed via frequent semiquantitative culture of bacteria from the ulcer surface and determination of the ulcer area over a period of 180 days. Occurrences of cellulitis were treated with systemic antibiotics. There was a significant difference in relative areas on days 90 and 180 when ulcers with growth of Pseudomonas aeruginosa were compared to those without (p = 0.0080 and 0.0133, respectively). Ulcers with P. aeruginosa were characterized to a great extent by enlargement in contrast to those without. Ulcers with growth of Staphylococcus aureus or haemolytic streptococci healed significantly more slowly than those without when relative areas were compared on day 180 (p = 0.0079 and 0.0492, respectively). Complete healing within the observation period of 180 days was observed in 10.5% of patients with P. aeruginosa and 35% of those without (p = 0.0631), in 21.6% of patients with S. aureus and 62.5% of those without (p = 0.0278), and in 10.5% of patients with haemolytic streptococci and 35% of those without (p = 0.0631). The initial areas of ulcers colonized with P. aeruginosa or S. aureus were significantly larger than those without, but no significant correlation between initial areas and ulcer healing was revealed.

Our results suggest that P. aeruginosa in venous leg ulcers can induce ulcer enlargement and/or cause a healing delay. The results also suggest a healing delay caused by S. aureus and haemolytic streptococci. However, conclusions have to be treated with caution since P. aeruginosa was found in combination with haemolytic streptococci in 15.3% of the patients.