Title : Appropriateness of microbiological pus swabs following incision and drainage of cutaneous abscesses: A closed-loop audit of antimicrobial stewardship
Abstract:
Introduction: Incision and drainage is the definitive treatment for most cutaneous abscesses, and the majority of patients are discharged without antibiotics. No NICE guideline specifically addresses swabbing of primary cutaneous abscesses. We therefore applied the antimicrobial-stewardship concept of NICE NG125 which promotes targeted microbiological sampling to guide, rather than routinely accompany, treatment to rationalise swab-taking in this setting. On this basis, culture was considered indicated only in selected cases: systemic features of infection, severe or complex local infection, recurrence, treatment failure, or immunocompromise. Routine swabbing of uncomplicated abscesses rarely alters management and incurs avoidable laboratory cost.
Aims: To assess whether pus swabs taken at abscess drainage were clinically indicated under stewardship-based criteria, and whether their results influenced management, against a standard of 100% appropriate use.
Methods: A retrospective audit was conducted at a single hospital over 3 months. Consecutive patients undergoing incision and drainage of a cutaneous abscess were identified. Applying the NG125-derived stewardship criteria, each case was assessed for the presence of an accepted indication for swabbing, whether a swab was taken, the result, and any consequent change in management (antibiotic initiation/change or microbiology input). Patients not undergoing drainage were excluded.
Results: Fifty-one patients were included (median age 48 years; range 17–93); the commonest sites were perianal and pilonidal. A swab was taken in 33 patients (65%), the majority of whom had no accepted indication. Overall, only 20 of 51 patients (39%) were managed appropriately (swab correctly taken or correctly omitted). Among patients swabbed without indication, the result changed management in only one case, and 26 of 31 (84%) had no change to treatment irrespective of the result. No patient required an antibiotic change on the basis of swab sensitivities alone.
Conclusion: Most pus swabs were taken without an accepted indication and did not influence management, representing avoidable laboratory cost and workload contrary to antimicrobial-stewardship principles. Applying the stewardship concept of NG125 provided a practical framework to rationalise sampling. A combined intervention of departmental teaching and an integrated swab-indication prompt within the operative and discharge pathway was introduced. A second cycle is currently underway and will additionally involve the microbiology team to further strengthen swab rationalisation, with its impact to be assessed.
