Antibiotic use in the treatment of chronic wounds

Abstract

Chronic wounds cause substantial morbidity and healthcare costs and prevalence is rising as the population ages and diabetes increases. Microbes are ubiquitous in chronic wounds, with Staphylococcus aureus and Pseudomonas aeruginosa commonplace. Antibiotic resistance is also widespread and increasing. Patients with chronic wounds are exposed to many antibiotic resistance risk factors. This study investigated antibiotic consumption by patients with chronic wounds and the prevalence of and risk factors for antibiotic resistant organisms in such wounds. Finally, the impact of resistance on the cost of treatment was investigated. Antibiotic consumption by patients with chronic wounds treated in primary care was significantly higher than matched patients without chronic wounds. This included greater quantities of flucloxacillin, co-amoxiclav, metronidazole, and ciprofloxacin. The prevalence of antibiotic resistant organisms in chronic wounds of patients attending a specialist wound-healing clinic was investigated. No patients carried vancomycin- resistant enterococci in their wounds. The prevalence of methicillin-resistant S. aureus (MRSA) was 10%. No wound characteristics were associated with MRSA. Carriage was associated with previous MRSA and 'other' systemic antibiotics. The prevalence of ciprofloxacin-resistant P. aeruginosa was 11%. Exploratory analysis identified previous antibiotics (specifically ciprofloxacin, 'other' topical antimicrobials and 'other' systemic antibiotics) and wound aetiology as risk factors. Healing wounds were less likely to carry ciprofloxacin-resistant P. aeruginosa. Treatment costs for venous leg ulcers were explored using Markov models: one year's treatment, following presentation, cost £1008. Antibiotic resistance prevalence had little impact on cost. The frequency of nursing visits (for healed and active ulcers), cost of hospital appointments and cost of nurses had the greatest impact. In summary, antibiotics are commonly used in primary care management of chronic wounds. However ciprofloxacin and 'other' systemic antibiotics may be associated with carriage of antibiotic resistant organisms. The impact of resistance on treatment costs of venous ulcers is small, provided effective alternatives are available