Metabolism gene signatures and surgical site infections in abdominal surgery

• Surgical site infections (SSI) are related to both wound contamination with microorganisms and host susceptibility.
• We identified a unique gene expression signature in subcutaneous tissues of patients who developed SSI.
• Genes controlling cell metabolism were mostly down-regulated in subcutaneous tissues of those patients.
• This suggests increased inherent tissue susceptibility to infection due to locally reduced metabolic activity.

IntroductionSurgical site infections (SSI) represent a significant cause of morbidity in abdominal surgery. The objective of this study was to determine the gene expression signature in subcutaneous tissues in relation to SSI.MethodsTo determine differences in gene expression, microarray analysis were performed from bulk tissue mRNA of subcutaneous tissues prospectively collected in 92 patients during open abdominal surgery. 10 patients (11%) developed incisional (superficial and deep) SSI.ResultsPreoperative risk factors in patients with SSI were not significantly different from those in patients without wound infections. 1025 genes were differentially expressed between the groups, of which the AZGP1 and ALDH1A3 genes were the highest down- and upregulated ones. Hierarchical clustering demonstrated strong similarity within the respective groups (SSI vs. no-SSI) indicating inter-group distinctness. In a functional classification, genes controlling cell metabolism were mostly down-regulated in subcutaneous tissues of patients that subsequently developed SSI.ConclusionAltered expression of metabolism genes in subcutaneous tissues might constitute a risk factor for postoperative abdominal SSI.