[Profile of Buruli ulcer treated at the National Reference Centre of Togo: a study of 119 cases]

Systematic review: Global host range, case fatality and detection rates of Mycobacterium ulcerans in humans and potential environmental sources

Fundamental aspects of the epidemiology and ecology of Mycobacterium ulcerans (MU) infections including disease burden, host range, reservoir, intermediate hosts, vector and mode of transmission are poorly understood. Understanding the global distribution and burden of MU infections is a paramount to fight against Buruli ulcer (BU). Four databases were queried from inception through December 2023. After critical review of published resources on BU, 155 articles (645 records) published between 1987 and 2023 from 16 countries were selected for this review. Investigating BU in from old endemic and new emerging foci has allowed detection of MU in humans, animals, plants and various environmental samples with prevalence from 0 % up to 100 % depending of the study design. A case fatality rate between 0.0 % and 50 % was described from BU patients and deaths occurred in Central African Republic, Gabon, Democratic Republic of the Congo, Burkina Faso and Australia. The prevalence of MU in humans was higher in Africa. Nucleic Acid Amplification Tests (NAAT) and non-NAAT were performed in > 38 animal species. MU has been recovered in culture from possum faeces, aquatic bugs and koala. More than 7 plant species and several environmental samples have been tested positive for MU. This review provided a comprehensive set of data on the updates of geographic distribution, the burden of MU infections in humans, and the host range of MU in non-human organisms. Although MU have been found in a wide range of environmental samples, only few of these have revealed the viability of the mycobacterium and the replicative non-human reservoirs of MU remain to be explored. These findings should serve as a foundation for further research on the reservoirs, intermediate hosts and transmission routes of MU.

A case of squamous cell carcinoma occurring on a scar of Buruli ulcer in Bouake, Ivory Coast

Buruli ulcer is infectious necrotizing panniculitis due to Mycobacterium ulcerans. Buruli ulcer is healed by leaving dystrophic, fibrous and retractile scars. On these scars can occur long-term squamous cell carcinoma. We report the first case of squamous cell carcinoma occurring on healing of Buruli ulcer. A 32-year-old woman with Buruli ulcer who has been cured for about 10 years is seen for ulcero-bulging knee swelling. The examination had revealed a large swelling of about ten centimeters in diameter, ulcero-budding, with an easily bleeding cauliflower appearance. The diagnosis of squamous cell carcinoma being retained without metastasis, resection of the tumor with scarring after one month without chemotherapy. There was no recurrence after six months of decline. The epidemiology of Buruli ulcer, responsible for scarring, explains the young age of our patient and the localization of carcinoma on the limb. The carcinomatous degeneration of scars, especially the scars of old burns, is constantly reported. The characteristics of Buruli ulcer scars, which bring them closer to burn scars, may explain why they are particularly affected by carcinomatous degeneration. One could also mention the chronicity of the wound in this infection, or wonder if the mycobacteria itself could play a role in carcinogenesis. This observation is, in our opinion, an alarm signal. We must fear an outbreak of cases in the years to come. To this end, preventive measures should already be taken by sensitizing the patients for an early consultation before any modification of their scars. After recovery, Buruli ulcer seems to present a risk of long-term evolution to a cancer. The scars of this condition, which could be considered precancerous lesions.

Drugs for treating Buruli ulcer (Mycobacterium ulcerans disease)

BACKGROUND

Buruli ulcer is a necrotizing cutaneous infection caused by infection with Mycobacterium ulcerans bacteria that occurs mainly in tropical and subtropical regions. The infection progresses from nodules under the skin to deep ulcers, often on the upper and lower limbs or on the face. If left undiagnosed and untreated, it can lead to lifelong disfigurement and disabilities. It is often treated with drugs and surgery.

OBJECTIVES

To summarize the evidence of drug treatments for treating Buruli ulcer.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE (PubMed); Embase (Ovid); and LILACS (Latin American and Caribbean Health Sciences Literature; BIREME). We also searched the US National Institutes of Health Ongoing Trials Register (clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en/). All searches were run up to 19 December 2017. We also checked the reference lists of articles identified by the literature search, and contacted leading researchers in this topic area to identify any unpublished data.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared antibiotic therapy to placebo or alternative therapy such as surgery, or that compared different antibiotic regimens. We also included prospective observational studies that evaluated different antibiotic regimens with or without surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, extracted the data, and assessed methodological quality. We calculated the risk ratio (RR) for dichotomous data with 95% confidence intervals (CI). We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included a total of 18 studies: five RCTs involving a total of 319 participants, ranging from 12 participants to 151 participants, and 13 prospective observational studies, with 1665 participants. Studies evaluated various drugs usually in addition to surgery, and were carried out across eight countries in areas with high Buruli ulcer endemicity in West Africa and Australia. Only one RCT reported adequate methods to minimize bias. Regarding monotherapy, one RCT and one observational study evaluated clofazimine, and one RCT evaluated sulfamethoxazole/trimethoprim. All three studies had small sample sizes, and no treatment effect was demonstrated. The remaining studies examined combination therapy.Rifampicin combined with streptomycinWe found one RCT and six observational studies which evaluated rifampicin combined with streptomycin for different lengths of treatment (2, 4, 8, or 12 weeks) (941 participants). The RCT did not demonstrate a difference between the drugs added to surgery compared with surgery alone for recurrence at 12 months, but was underpowered (RR 0.12, 95% CI 0.01 to 2.51; 21 participants; very low-certainty evidence).An additional five single-arm observational studies with 828 participants using this regimen for eight weeks with surgery (given to either all participants or to a select group) reported healing rates ranging from 84.5% to 100%, assessed between six weeks and one year. Four observational studies reported healing rates for participants who received the regimen alone without surgery, reporting healing rates ranging from 48% to 95% assessed between eight weeks and one year.Rifampicin combined with clarithromycinTwo observational studies administered combined rifampicin and clarithromycin. One study evaluated the regimen alone (no surgery) for eight weeks and reported a healing rate of 50% at 12 months (30 participants). Another study evaluated the regimen administered for various durations (as determined by the clinicians, durations unspecified) with surgery and reported a healing rate of 100% at 12 months (21 participants).Rifampicin with streptomycin initially, changing to rifampicin with clarithromycin in consolidation phaseOne RCT evaluated this regimen (four weeks in each phase) against continuing with rifampicin and streptomycin in the consolidation phase (total eight weeks). All included participants had small lesions, and healing rates were above 90% in both groups without surgery (healing rate at 12 months RR 0.94, 95% CI 0.87 to 1.03; 151 participants; low-certainty evidence). One single-arm observational study evaluating the substitution of streptomycin with clarithromycin in the consolidation phase (6 weeks, total 8 weeks) without surgery given to a select group showed a healing rate of 98% at 12 months (41 participants).Novel combination therapyTwo large prospective studies in Australia evaluated some novel regimens. One study evaluating rifampicin combined with either ciprofloxacin, clarithromycin, or moxifloxacin without surgery reported a healing rate of 76.5% at 12 months (132 participants). Another study evaluating combinations of two to three drugs from rifampicin, ciprofloxacin, clarithromycin, ethambutol, moxifloxacin, or amikacin with surgery reported a healing rate of 100% (90 participants).Adverse effects were reported in only three RCTs (158 participants) and eight prospective observational studies (878 participants), and were consistent with what is already known about the adverse effect profile of these drugs. Paradoxical reactions (clinical deterioration after treatment caused by enhanced immune response to M ulcerans) were evaluated in six prospective observational studies (822 participants), and the incidence of paradoxical reactions ranged from 1.9% to 26%.

AUTHORS' CONCLUSIONS

While the antibiotic combination treatments evaluated appear to be effective, we found insufficient evidence showing that any particular drug is more effective than another. How different sizes, lesions, and stages of the disease may contribute to healing and which kind of lesions are in need of surgery are unclear based on the included studies. Guideline development needs to consider these factors in designing practical treatment regimens. Forthcoming trials using clarithromycin with rifampicin and other trials of new regimens that also address these factors will help to identify the best regimens.

[Squamous cell carcinoma secondary to Buruli ulcer in West Africa]

BACKGROUND

Buruli ulcer is an infection caused by Mycobacterium ulcerans occurring in tropical areas. In West Africa, it is an emerging threat mainly affecting children aged under 15years. This chronic disease is complicated by dystrophic scars in which squamous cell carcinoma can occur in the long term.

PATIENTS AND METHODS

This is a retrospective study of squamous cell carcinomas in Buruli ulcer scars seen at the Treichville University Hospital (Abidjan, Ivory Coast) over a five-year period.

RESULTS

During the study period, 8cases were observed and concerned young adults presenting Buruli ulcer in their childhood. Tumours were restricted to the limbs, with loco-regional invasion. Treatment was primarily surgical. Four of the patients died.

DISCUSSION

The risk of recurrence of cancer in these scars remains poorly evaluated, highlighting the importance of long-term monitoring strategies for human patients in order to ensure rapid identification of any changes in Buruli ulcer scars.

Buruli ulcer control in a highly endemic district in Ghana: role of community-based surveillance volunteers

Buruli ulcer (BU) is an infectious skin disease that occurs mainly in West and Central Africa. It can lead to severe disability and stigma because of scarring and contractures. Effective treatment with antibiotics is available, but patients often report to the hospital too late to prevent surgery and the disabling consequences of the disease. In a highly endemic district in Ghana, intensified public health efforts, mainly revolving around training and motivating community-based surveillance volunteers (CBSVs), were implemented. As a result, 70% of cases were reported in the earliest-World Health Organization category I-stage of the disease, potentially minimizing the need for surgery. CBSVs referred more cases in total and more cases in the early stages of the disease than any other source. CBSVs are an important resource in the early detection of BU.

Mycobacterium ulcerans Disease with Unusual Sites Not to Be Ignored

Objective. The usual preferential site of BU is in the limbs. In our experience, we noticed atypical and often misleading sites which pose serious issues for the diagnosis and often for the treatment. Methods. This is a retrospective study conducted over a period of ten years of BU treatment at the Department of Dermatology of the University Teaching Hospital of Treichville (Abidjan, Côte d'Ivoire). We included in this study all BU cases with atypical site diagnosed clinically and confirmed either by the histology, by smear, or by PCR. Results. Epidemiologically, the age of patients ranged from 3 to 72 years with a median age of 14.2 years. Children aged less than 15 years were affected in almost 80% of case. The clinical table was dominated by ulcerated forms in 82.1% of cases. The unusual topography mostly observed was that of the torso (thorax, back, and abdomen) in 76.8% of cases. Conclusion. BU is an endemic disease in Côte d'Ivoire where it constitutes a serious public health issue. Several years following its first cases, BU still is little known. This dermatosis may present atypical misleading clinical aspects which must be ignored.

Clinical efficacy of Rifampicin and Streptomycin in combination against Mycobacterium ulcerans infection: a systematic review

Buruli ulcer (BU) is a cutaneous neglected tropical disease caused by Mycobacterium ulcerans. Synthesizing the evidence on their efficacy of antibiotic in the management of BU can help to better define their roles, identify weaknesses and inform clinicians on relevant measures than can be used to control BU. Our objectives is to assess the clinical efficacy of Rifampicin-Streptomycin given for 8 weeks of treatment of early M. ulcerans infection. We searched the following electronic databases from January 2005 to July 2012: Medline, EMBASE (Excerpta Medica Database), The Cochrane Library, Google Scholar, CINAHL (Cumulative Index to Nursing and Allied Health Literature), WHOLIS (World Health Organization Library Database), LILACS (Latin American and Caribbean Literature on Health Sciences) and contacted experts in the field. There were no restrictions to language or publication status. All study designs that could provide the information we sought for were eligible provided the studies were conducted in the third world. Critical appraisal of all identified citations was done independently by three authors to establish the possible relevance of the articles for inclusion in the review. Of the 115 studies, 09 papers met the inclusion criteria. The duration of treatment ranged from 8 to 48 weeks depending on the severity. Oral chemotherapy alone obtained a curative rate of 50%. The “dual” mode of treatment (surgery + chemotherapy) reduced hospital admission period from 90 to 39.8 days, that's to 44.2%. This treatment for early stages could therefore replace surgery and in severe cases, is an indispensable aid before surgery. These results confirmed that the daily administration of Rifampicin and Streptomycin is an effective treatment for M. ulcerans infection in an early stage. Subsequent systematic reviews should be conducted to determine if antibiotics could heal injuries without resorting to surgery and to compare different treatment durations.

Geographic distribution, age pattern and sites of lesions in a cohort of Buruli ulcer patients from the Mapé Basin of Cameroon

Buruli ulcer (BU), a neglected tropical disease of the skin, caused by Mycobacterium ulcerans, occurs most frequently in children in West Africa. Risk factors for BU include proximity to slow flowing water, poor wound care and not wearing protective clothing. Man-made alterations of the environment have been suggested to lead to increased BU incidence. M. ulcerans DNA has been detected in the environment, water bugs and recently also in mosquitoes. Despite these findings, the mode of transmission of BU remains poorly understood and both transmission by insects or direct inoculation from contaminated environment have been suggested. Here, we investigated the BU epidemiology in the Mapé basin of Cameroon where the damming of the Mapé River since 1988 is believed to have increased the incidence of BU. Through a house-by-house survey in spring 2010, which also examined the local population for leprosy and yaws, and continued surveillance thereafter, we identified, till June 2012, altogether 88 RT-PCR positive cases of BU. We found that the age adjusted cumulative incidence of BU was highest in young teenagers and in individuals above the age of 50 and that very young children (<5) were underrepresented among cases. BU lesions clustered around the ankles and at the back of the elbows. This pattern neither matches any of the published mosquito biting site patterns, nor the published distribution of small skin injuries in children, where lesions on the knees are much more frequent. The option of multiple modes of transmission should thus be considered. Analyzing the geographic distribution of cases in the Mapé Dam area revealed a closer association with the Mbam River than with the artificial lake.

Buruli ulcer (BU) is an infectious disease caused by Mycobacterium ulcerans that is affecting mostly children in endemic areas of West Africa. Proximity to slow flowing water is a risk factor, but the exact mode of transmission of BU remains unclear. Man-made environmental changes, such as sand mining, damming of rivers and irrigation have been implicated with increases in disease incidence. Here, we report findings from a survey for BU and continued case detection thereafter in the Bankim Health District of Cameroon. In this area, the local population believed that the damming of the Mapé River has led to the emergence of BU. In 28 months we identified 88 laboratory confirmed cases of BU. Studying these cases, we found that the age adjusted cumulative incidence of BU in the elderly is similar to that in children and that the distribution pattern of BU lesions neither matches mosquito biting patterns nor the distribution of small skin injuries. Multiple modes of transmission should therefore be considered. Our data further showed that the patients appear to have closer contact to the local Mbam River than to the artificial Mapé dam reservoir.