Maintenance of wound bacterial balance

BACKGROUND: There is a critical number of bacteria above which tissue responds with infection. This balance of 10(5) or fewer bacteria/g tissue is also required for wound healing to proceed normally. This study evaluated whether a chronic wound once in bacterial balance can maintain that balance over time. METHODS: Serial biopsies for bacterial analyses were obtained weekly during a blinded, placebo-controlled cytokine clinical trial of pressure ulcers. To enter the trial ulcers had to be debrided and have a bacterial count of 105 or fewer bacteria/g tissue with no beta-hemolytic streptococci. RESULTS: In all, 96% of cultures (350/363) remained at <10(2) bacteria/g tissue over the 5-week trial; 3% had 10(2) to 105, and only 1% had >10(5) bacteria/g tissue. CONCLUSION: Chronic pressure ulcers, once debrided and brought into bacterial balance, will remain in bacterial balance if cared for and kept free of necrotic tissue.