A descriptive study of bacterial load of full-thickness surgical wounds in dermatologic surgery

Abstract

Background: Surgical site infections (SSIs) after dermatologic surgery cause pain, prolong healing, result in unaesthetic complications, and lead to excessive use of antibiotics. The pathogenesis of wound infections is complex and is dependent on bacterial load and diversity, among several factors.

Objective: To investigate bacterial dynamics at dermatosurgical sites at different time intervals and assess the correlation with postoperative outcomes and to examine different endo- and exogenous factors that may contribute to SSIs.

Methods: Eighteen patients undergoing skin grafting of the face were studied. The following SSI-related factors were registered: age and sex of the patient, ulceration of the lesion, diabetes, immunosuppressive therapy, smoking, anticoagulative therapy, and use of antibiotic prophylaxis. Wounds from each patient were swabbed preoperatively, intraoperatively, and postoperatively. The bacterial composition of the swabs was then analyzed quantitatively and qualitatively.

Results: Sixteen of 18 surgical sites contained varying quantities of surface-associated bacteria. Coagulase-negative staphylococci and Propionibacterium acnes were the predominant bacteria isolated at all times. Intraoperative analysis was not predictive of SSIs. Use of antibiotic prophylaxis was the only registered SSI-related factor that showed significant variation in bacterial load between pre- and postoperative samples. Postoperative bacterial load was found to be lower than preoperative load in patients who received antibiotics. This was in contrast to patients who did not receive antibiotics, who had significantly higher postoperative levels (p=.02). The presence of high postoperative bacterial loads, regardless of the bacterial species isolated, showed a statistically significant positive correlation with a complicated postoperative outcome (p≤.001).

Conclusions: This study provides novel insights into the bacterial dynamics of dermatologic surgery-induced wounds and the variation of this over time. The results highlight the potential relevance of quantifying bacterial loads, as well as determining specific types of bacteria, in dermatologic surgery.