Burn type-specific differences in the bacterial microbiome of burn scars between electrical and flame burns

Whether the burn scar skin microbiome differs according to burn type remains unknown. This prospective cross-sectional study compared the skin microbiome of burn scars and contralateral unburned skin between 30 male patients with electrical burns and 30 age-, total body surface area burned- and burn depth-matched patients with flame burns using 16 S rRNA gene amplicon sequencing. Direct comparison of burn scars showed no significant alpha diversity differences, but intra-individual scar-to-unburned skin changes differed significantly between burn types across all alpha diversity metrics (e.g., median Δ Shannon index: −0.25 in electrical vs. − 0.00 in flame burns, p = 0.002). Beta diversity differed between electrical and flame burn scars only in Aitchison distance-based PERMANOVA (R² = 0.019, p = 0.032), whereas unburned skin differed across all tested metrics. Electrical burn scars formed the largest and most densely connected microbial co-occurrence network, with 130 nodes and 767 edges, and were enriched in environmentally stress-adapted taxa, including Nesterenkonia and Aliidiomarina . Flame burn scars showed enrichment of Pseudomonas E and a more modular network structure. Two taxon-clinical indicator pairs showed significantly opposite correlations with Vancouver Scar Scale total score between burn types (e.g., Finegoldia : ρ = −0.33 vs. 0.58; q = 0.043) after false discovery rate correction. These findings suggest that burn type may be associated with differences in the scar microenvironment and associated microbial ecology among male burn patients and may inform future research on burn type-specific microbiome-based strategies.