To access this article, click on "Additional Links"OBJECTIVE: To describe the effect of antibiotics on outcomes of treatment for Buruli or Bairnsdale ulcer (BU) in patients on the Bellarine Peninsula in south-eastern Australia. DESIGN: Observational, non-randomised study with data collected prospectively or through medical record review. PATIENTS AND SETTING: All 40 patients with BU managed by staff of Barwon Health's Geelong Hospital (a public, secondary-level hospital) between 1 January 1998 and 31 December 2004. MAIN OUTCOME MEASURES: Epidemiology, clinical presentation, diagnosis, treatment and clinical outcomes. RESULTS: There were 59 treatment episodes; 29 involved surgery alone, 26 surgery plus antibiotics, and four antibiotics alone. Of 55 episodes where surgery was performed, minor surgery was required in 22, and major surgery in 33. Failure rates were 28% for surgery alone, and 19% for surgery plus antibiotics. Adjunctive antibiotic therapy was associated with increased treatment success for lesions with positive histological margins (P < 0.01), and lesions requiring major surgery for treatment of a first episode (P < 0.01). The combination of rifampicin and ciprofloxacin resulted in treatment success in eight of eight episodes, and no patients ceased therapy because of side effects with this regimen. CONCLUSIONS: Adjunctive antibiotic therapy may increase the effectiveness of BU surgical treatment, and this should be further assessed by larger randomised controlled trials. The combination of rifampicin and ciprofloxacin appears the most promising.