Six vs Eight Weeks of Antibiotics for Small Mycobacterium ulcerans Lesions in Australian Patients

Background: Antibiotics are highly effective in curing Mycobacterium ulcerans lesions, but are associated with significant toxicity. In those not undergoing surgery, we compared 6 weeks with the currently recommended 8 weeks of combination antibiotic therapy for small M. ulcerans lesions. Methods: Mycobacterium ulcerans cases from an observational cohort at Barwon Health, Victoria, treated with antibiotics alone from 1 October 2010 to 31 March 2018 were included. The 6-week antibiotic group received >= 28 days and <= 42 days and the 8-week antibiotic group received >= 56 days of antibiotic therapy, respectively. Only World Health Organization category 1 lesions were included. Results: 207 patients were included; 53 (25.6%) in the 6-week group and 154 (74.4%) in the 8-week group. The median age of patients was 53 years (interquartile range [IQR], 33-69 years) and 100 (48.3%) were female. Lesions were <= 900 mm(2) in size in 79.7% of patients and 93.2% were ulcerative. Fifty-three patients (100%) achieved treatment cure in the 6-week group compared with 153 (99.4%) in the 8-week group (P = .56). No patients died or were lost to follow-up during the study. Median time to heal was 70 days (IQR, 60-96 days) in the 6-week group and 128 days (IQR, 95-173 days) in the 8-week group (P < .001). Two (3.8%) patients in the 6-week group experienced a paradoxical reaction compared with 39 (25.3%) patients in the 8-week group (P = .001). Conclusions: For selected small M. ulcerans lesions, 6 weeks may be as effective as 8 weeks of combined antibiotic therapy in curing lesions without surgery.