Is the pre-operative wound culture necessary before skin grafting minor burns? A pilot study in a low resource setting burn service.

The most common cited cause of split-thickness skin graft failure is infection and due to the association between bacterial findings in wound beds an attempt to decrease the bacterial burden before skin-grafting evolved. Thus, pre-operative microbiology swabs of the wound bed became routine at some institutions prior to grafting. This is not standard practice in the Pietermaritzburg burn service. Emphasis is instead placed on a strict protocol of intra-operative wound bed preparation to promote adequate graft take. This pilot study aims to evaluate whether pre-operative wound swabs are appropriate. We performed a prospective observational study to determine if positive wound cultures were associated with graft failure. All patients with a burn surface area of less than 10 %, where delayed grafting (later than 28 days from time of burn injury) was performed, from March to December 2021 were analyzed. Patient demographics, days from burn to graft, %TBSA burn, %TBSA grafted, whether sharp debridement prior to grafting in the same procedure was performed or not, use of topical gentamicin intra-operatively, graft outcome (% graft loss), need for regraft, and organism grown were recorded into an excel spread sheet for analysis. The sample included 52 patients. Of these, 17 (31.5%) were female. The median %TBSA grafted was 8% (IQR 4-13%) and similar in both groups. The median days from burn to grafting was 35 days. Thirty-nine patients (75%) had graft Take and 13 (25%) had graft Failure. In the failed group, median % graft failure was 50% (30 - 70%). Of the group with successful graft take, 90% were noted to have had a positive wound culture prior to grafting. A positive wound culture was not found to be a risk factor for graft failure (p=0.993). Despite the positive wound cultures graft take was more than 90 % in 75% of grafts performed and only 2/52 patients required supplementary grafting. We believe that this demonstrates that our local protocol is reasonable in this setting and that waiting for negative wound swabs prior to grafting should not be a reason to delay grafting.