A Systematic Review and Meta-Analysis Comparing the Diagnostic Accuracy of Swab Cultures and Tissue Biopsy for...

To evaluate and compare the diagnostic accuracy and concordance of swab cultures and tissue biopsy for identifying causative pathogens. Furthermore, to compare the sensitivity, specificity and overall diagnostic performance of swab cultures and tissue biopsies, using tissue biopsy as the reference standard in infected diabetic foot wounds.

We conducted a systematic review and meta-analysis using CINAHL, Embase and PubMed for published studies from inception to April 2025. Eligible studies compared the diagnostic accuracy or the list of pathogens of swab cultures and tissue biopsy in adult patients diagnosed with diabetic foot infections. A random-effects diagnostic accuracy meta-analysis was undertaken.

Seventeen studies were included. Swab cultures identified 765 Gram-positive microbial pathogens compared to 875 identified by tissue biopsies and 457 Gram-negative pathogens compared to 452 identified by tissue biopsies. The three most prevalent microbial species were Staphylococcus aureus, Streptococcus spp. and Enterococcus spp. Pooled sensitivity and specificity of swab cultures for detecting infected diabetic foot wounds were 84.8% and 68.0%, respectively, using tissue biopsy as the reference standard. Subgroup analyses indicated better pooled sensitivity and specificity for Gram-negative (85.2% and 92.9%, respectively) compared to Gram-positive pathogens (76.8% and 81.0%, respectively).

Our findings are that swab cultures could identify Gram-negative pathogens and may still be acceptable for detecting Gram-positive and overall infections. While tissue biopsy remains the reference standard, swab cultures may represent a practical and accessible alternative in situations where tissue biopsy is not feasible or not performed.