Effectiveness of rifampicin-streptomycin for treatment of Buruli ulcer: a systematic review
Authors: Tanywe Asahngwa , Fernandez Ritin S. 
Published: January 2017

EXECUTIVE SUMMARY

Background
Buruli ulcer (BU) disease is a chronic ulcerative skin disease caused by Mycobacterium ulcerans, which can lead to extensive destruction of the skin, soft tissues and occasionally of bones. Although several antibiotics have demonstrated bactericidal activity against M. ulcerans in vitro, no consensus on their clinical efficacy against M. ulcerans in humans has been reached.

Objectives
The objective of the systematic review was to examine the clinical effectiveness of various antibiotic regimens for the treatment of BUs.

Inclusion criteria Types of participants
The current review considered trials that included patients of all ages with BUs.

Types of intervention(s)
The current review considered trials that evaluated antibiotic regimens compared to no antibiotics or surgery in patients with BUs.

Types of studies
The current review considered randomized and non-randomized controlled trials (RCTs). In the absence of RCTs, other research designs such as before and after trials and clinical trials with only an intervention arm were considered for inclusion in a narrative summary.

Outcomes
The primary outcome of interest were the treatment success rates among the various antibiotics used. Secondary outcomes included changes in lesion size, recurrence of ulcers and incidence of adverse events.

Search strategy
The search strategy aimed to find both published and unpublished trials. A three-step search strategy was utilized in this review and included English language trials published after 1990. A search across the major databases was conducted up to December 2014.

Methodological quality
Using the Joanna Briggs Institute (JBI) standardized appraisal tool, two reviewers independently assessed the methodological quality of the trials. A third independent reviewer was available to appraise trials if the two original reviewers disagreed in their assessments. There were no disagreements in findings between the two independent reviewers.

Data extraction
Data were extracted using the standardized JBI data extraction instruments.

Data synthesis
Statistical pooling was not possible due to heterogeneity, hence results have been presented in the narrative form.

Results
Seven studies involving a total of 712 patients were included in the final review. Higher treatment success rates ranging from 96% to 100% at the six months follow-up were reported among patients treated with rifampicin-streptomycin for eight weeks (RS8) in two studies. Treatment success with rifampicin-streptomycin for 12 weeks, with surgery at the 12 weeks follow-up, was 91%. In the two studies that investigated the effect of rifampicin-streptomycin for two weeks followed by rifampicin-clarithromycin for six weeks and rifampicin-streptomycin for four weeks followed by rifampicin-clarithromycin for four weeks, treatment success was reported to be 93% and 91%, respectively, at the 12 months follow-up. A significant decrease in the median lesion size at the eight weeks follow-up was reported in patients who were treated with RS8, and a 10-30% decrease in lesion size was reported in those treated with RS12 at the four weeks follow-up.

Conclusion
Treatment success and reduction in lesion size were higher in patients treated with RS8 in the only RCT that compared rifampicin-streptomycin for four weeks followed by rifampicin-clarithromycin for six weeks to RS8, and there was no difference in outcomes, which indicates that local preferences could dictate the treatment option. Evidence obtained from this systematic review indicates that surgery will remain necessary for some ulcers; however, detection of early lesions and treatment with antibiotics would have a greater impact on the control of M. ulcerans disease. Further large multicenter RCTs investigating the type and optimal duration of oral antibiotic treatment for patients with M. ulcerans disease are urgently needed.