The wound microbiome associated with deep sternal wound infection: a scoping review

Deep sternal wound infection (DSWI) is a serious complication following cardiovascular surgery, increasing patient mortality and healthcare burden. Understanding the wound microbiome, including microbial load, microbial diversity, presence/abundance of common wound microorganisms, and biofilm formation, is crucial for improving infection prevention, diagnosis, and management. This scoping review aims to: (I) summarize DSWI definitions, specimen acquisition methods, and microbial identification techniques; (II) synthesize current DSWI literature regarding microbial load, microbial diversity, presence/abundance of common wound microorganisms, and biofilm formation.

A scoping review was conducted using PubMed and EMBASE to identify studies on the wound microbiome in DSWI. Studies were included if they were in English, focused on adults, and published in journals. Exclusion included secondary sources, case reports, transplant populations, and other nosocomial infections. Data extraction followed a standardized approach, and findings were synthesized narratively, with a table summarizing study details. Seventy-one studies were included in this scoping review.

The Centers for Disease Control and Prevention (CDC) criteria were most commonly used for DSWI. Specimen location was unspecified in 60.6% of studies, while 14.1% specified the mediastinum. Methods of specimen acquisition were reported in only 25.3% of studies. Culture techniques were predominant (91.5%), while molecular or imaging methods were used in only 8.5%. Among studies using culture, Staphylococcus aureus was the most common microorganism, and 22.5% investigated polymicrobial infections. Molecular studies identified resistance genes such as blaZ in Staphylococci and blaKPC in carbapenem-resistant Enterobacteriaceae (CRE). Biofilm formation was examined in only 2.8% of studies, with findings linking staphylococci to biofilm presence in DSWI.

This review revealed critical gaps in DSWI research, including poor reporting of specimen acquisition, a narrow focus on common wound microorganisms, and an overreliance on culture-based methods. The lack of standardized specimen collection reporting reduces data reliability and comparability. Limited use of molecular techniques restricts insights into microbial complexity. Advanced molecular techniques, including polymerase chain reaction, 16S ribosomal RNA (rRNA) sequencing, and metagenomic sequencing, are needed to improve microbiome characterization. Addressing these gaps will improve infection prevention and management for DSWI.