Microbial and inflammatory profiling of pressure injuries and urinary tract infections in spinal cord injury: a prospective cohort study

Pressure injuries (PIs) are common in individuals with spinal cord injury (SCI) and increase the risk of infections, including urinary tract infections (UTIs), which may prolong hospitalisation. However, the role of PIs in the development of postoperative UTIs remains unclear. In this exploratory study, we investigated the relationship between the PI microbiome and urinary bacteria, and examined whether perioperative bacteriuria predicts prolonged hospital stay in patients undergoing reconstructive PI surgery. In this cohort study, 21 male patients with SCI and advanced-stage PIs undergoing reconstructive surgery were evaluated. Microbiome and urinary cytokine profiles were analysed at two postoperative time points: day 3 (early postoperative phase) and day 15 (after completion of antibiotic therapy). DNA from skin, PI tissue, and urine was analysed using 16S rRNA gene sequencing. Asymptomatic bacteriuria was present in 48% of patients on day 3 and 38% on day 15. Dominant urinary bacteria included Enterococcus, Klebsiella, Streptococcus, and Escherichia, which were associated with elevated urinary cytokine levels. High bacterial load (≥ 100,000 bacteria/mL) in urine on day 3 correlated with increased UTI incidence and frequency, although hospitalisation duration was unaffected. By day 15, urinary bacterial load was no longer associated with UTI incidence. The microbiota of PIs and adjacent skin were distinct from urinary microbiota, indicating minimal cross-contamination. Early perioperative high bacterial load is associated with increased urinary inflammation and a higher risk of postoperative UTIs in patients with SCI undergoing PI reconstruction. These findings support early infection monitoring and targeted preventive strategies to improve postoperative outcomes.