The association between pressure injury microbiome and wound healing: a systematic review

Introduction: Pressure injuries (PIs) are a significant clinical problem, particularly in elderly, bedridden, and spinal cord injury patients. Bacterial infections are a primary complication that often delays or prevents wound healing. This systematic review analysed the current evidence on the role of the PI microbiome in wound healing outcomes. Methods: A systematic search was conducted in three online databases, namely Embase, Medline, and Web of Science (latest search October 2024). In total, 20 studies met the inclusion criteria, of which three were interventional (randomised controlled trials (RCTs), n=2; pre-post study, n=1), and 17 were observational study designs (retrospective, n=6; prospective, n=8; and case-control, n=3) comprising 1'015 study participants (with 1'034 PIs). These studies examined the PI microbiome, mostly at PI grades III and IV, using culture-based and next-generation sequencing (NGS) techniques. Data extraction focused on microbial diversity, predominant species, and their association with wound healing. The risk of bias was categorised as moderate, mostly due to the absence of sample size justification, as assessed by the NHLBI tool. Results: The findings confirmed that Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Enterococcus spp., and Escherichia coli dominated the PI microbiomes. Microbiome composition varied according to PI severity and anatomical location. Molecular techniques have identified a more diverse microbiome than culture-based methods. Although no specific bacterial taxa have been found to be favourable for wound healing, many taxa were found to be detrimental to PI development, including Anaerococcus, Finegoldia, and Acinetobacter. Antibiotic resistance was common, particularly in S. aureus. Interventions targeting the microbiome, such as debridement and platelet-rich plasma therapy, have been shown to improve healing rates. Discussion: In conclusion, evidence showed that the composition of the PI microbiome might negatively associate to wound healing, with the dominance of anaerobes associated with delayed healing. Therefore, future PI treatments should prioritise patient-centred approaches that integrate advanced microbial profiling with rigorous clinical evaluation to optimise chronic wound management. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42024575143.