The microbiology of ulcerative skin cancers: does the presence of pathogenic bacteria increase the risk of postoperative complications?

Abstract

Background: To document the microbiology of ulcerative skin cancers, histological types, anatomical distribution and post-surgical complications among patients in KwaZulu-Natal and to determine whether a link exists between the presence of these bacteria and postoperative complications after resectional surgery and reconstruction.
Methods: One hundred swabs from ulcerative cancer wounds were collected from October 2015 to August 2017. The swabs were taken on admission according to swabbing protocol in the ward. Variables analysed were histology, anatomical site, microbiology, management and outcomes and patient specific risk factors – age, smoking, comorbidities and retroviral disease (RVD) status.
Results: Of the 100 skin cancer wounds, 87 cultured pathogenic bacteria: the majority were squamous cell carcinomas (SCC) (48%); the remaining tumours were sarcomas (17%), basal cell carcinomas (BCC) (14%), melanomas (14%) and other carcinomas (3%). Among the bacteria cultured, Staphylococcus aureus was the most common pathogen found in 47% of the wounds, followed by Pseudomonas (25%) and beta-haemolytic Streptococcus (15%). The most virulent of pathogens: beta-haemolytic Streptococcus was most frequently found in melanomas. Of the 74 wounds that underwent reconstruction, 24 had complications (wound sepsis, dehiscence, graft loss, flap sepsis). Although wound complications are multifactorial, it was observed that all 24 of the wounds that complicated cultured pathogenic bacteria (Staphylococcus aureus, Streptococcus and Pseudomonas). It was also found that there were 13 wounds that did not culture any pathogenic bacteria; these showed no complications on follow-up.
Conclusion: Although complications post-reconstruction of these lesions are multifactorial, the data from this study shows that pathogenic bacteria may play a role in increasing the post-surgical complication risk.