Overview: Development of Drugs Against Mycobacterium ulcerans

For many years, wide margin surgical excision of Buruli ulcer lesions has been the main approach for the treatment of Mycobacterium ulcerans disease. The WHO now recommends an eight-week course of oral antibiotics with a combination of rifampicin and clarithromycin in Africa. However, disease management is complicated by social stigma, lack of awareness, and limited access to healthcare facilities, resulting in underreporting and frequently late initiation of medical treatment. Inadequate initial treatment can drive permanent disabilities and also limited compliance to the eight-week therapy is a limitation. Therefore, search for a faster and more simple treatment modality is ongoing, focusing primarily on the testing of new tuberculosis drug candidates for the treatment of M. ulcerans disease.

Overview: Mycolactone , the Macrolide Toxin of Mycobacterium ulcerans

The acquisition by a Mycobacterium marinum-like progenitor of a plasmid encoding enzymes for the biosynthesis of the highly potent macrolide toxin mycolactone has set off the evolution of M. ulcerans toward a new mycobacterial species. While the selective advantage of producing mycolactone for survival in environmental niche(s) of the pathogen is unclear, there is no doubt that the cytotoxic, immunomodulatory, and analgesic properties of mycolactone are key for the establishment and progression of M. ulcerans infections in the host. Improved procedures for the isolation, handling, and detection of the amphiphilic and light-sensitive toxin have facilitated studies to unravel molecular mechanisms of mycolactone action on host cells in vitro and on cellular and immune responses in animal models. The pivotal role of mycolactone in the pathology of Buruli ulcer and the fact that the toxin has not been associated with other pathogens make it an ideal target for therapeutics/vaccines aiming at mycolactone neutralization and for the development of assays for the diagnosis of the disease.

Overview: Mycobacterium ulcerans Disease (Buruli Ulcer)

Enhanced international research efforts since the establishment of the Global BU Initiative in 1998 by the WHO have helped to advance our understanding of the epidemiology, and pathogenesis of Mycobacterium ulcerans infections. Improved methods to cultivate the extremely slow-growing pathogen from BU lesions have laid the groundwork for a variety of studies using M. ulcerans isolates, including the analysis of the genome and proteome of the pathogen, as well as drug susceptibility testing and analyses of host-pathogen interactions in vitro and in animal models. The identification of specific, high-copy number target sequences in the genome of M. ulcerans has enabled the development of diagnostic tests and assays to detect the pathogen in the environment. Important research questions remain about the reservoir(s) of M. ulcerans in aquatic environments, factors leading to or promoting transmission to hosts, and host-pathogen interactions resulting in chronic infection versus spontaneous healing.

Assessment of community knowledge, attitude, and stigma of Buruli ulcer disease in Southern Nigeria

Background

Poor knowledge can influence timely care-seeking among persons with Buruli ulcer disease (BUD).

Objectives

To assess community knowledge, attitude and stigma towards persons with BUD in endemic settings of Southern Nigeria.

Methods

This was a cross-sectional survey conducted among adult community members in four States of Southern Nigeria. A semi-structured interviewer-administered questionnaire was administered to all participants.

Results

Of 491 adults who completed the survey, 315 (64.2%) belonged to the ≤40 years age group, 257 (52.3%) were males and 415 (84.5%) had some formal education. The overall mean (SD) knowledge score was 5.5±2.3 (maximum 10). Only 172 (35.0%) of the participants had a good knowledge of BUD. A total of 327 (66.6%) considered BUD as a very serious illness. Also, there was a high-level of stigma against BUD patients; 372 (75.8%) of the participants felt compassion for and desire to help them, 77 (15.7%) felt compassion but tended to stay away from them, and 53 (10.8%) feared them because they may infect them with the disease. Having a formal education and ethnicity were independent predictors of good knowledge of BUD.

Conclusion

There is poor community knowledge of BUD in endemic settings of Southern Nigeria which influenced the attitude and perceptions of community members towards persons with BUD

Assessment of health care workers' knowledge, attitude and risk perception of Buruli ulcer disease in Southern Nigeria

Background

Poor knowledge of health care workers may be responsible for the under-diagnosis and low notification of Buruli ulcer (BU) in high-burden settings. This study assessed health care workers' knowledge, attitude and risk perception of BU in Southern Nigeria.

Methods

We conducted a cross-sectional survey among 186 health care workers recruited from 58 health facilities in four states of Southern Nigeria. A semi-structured interviewer-administered questionnaire was administered to all participants.

Results

The overall mean knowledge score was 8.8±2.7 (maximum 15). Only 29.0% (54/186) of the respondents had a good knowledge of BU. The mean (SD) attitude score was 4.5±1.2 (maximum 6). Also, 61.3% (114/) of the respondents had a good attitude towards BU. The overall mean (SD) risk perception score was 2.6±1.3 (maximum 5). Only 26.3% (49/) of the respondents had a good risk perception of BU disease. Previous training was an independent predictor of good knowledge (aOR 4.6), good attitude (aOR 3.8) and good risk perception (aOR 2.9) to BU.

Conclusions

Health care workers in endemic settings of Nigeria have poor knowledge of and poor risk perception of BU disease. Training of health care workers is recommended to address the identified gaps to ensure earlier diagnosis and referral to specialist centres.

Exposure Risk for Infection and Lack of Human-to-Human Transmission of Mycobacterium ulcerans Disease, Australia

We conducted epidemiologic and genetic analyses of family clusters of Mycobacterium ulcerans (Buruli ulcer) disease in southeastern Australia. We found that the incidence of M. ulcerans disease in family members was increased. However, the risk for exposure appeared short-term and not related to human-human transmission.

Impact of human immunodeficiency virus on the severity of buruli ulcer disease: results of a retrospective study in cameroon

The impact of human immunodeficiency virus (HIV) infection on Buruli ulcer (BU) severity and prevalence remains unclear. This study shows that patients who are HIV positive are at risk for BU. Notably, HIV-induced immunosuppression seems to have an impact on BU clinical presentation and disease evolution.

Background.

 Buruli ulcer is the third most common mycobacterial disease after tuberculosis and leprosy and is particularly frequent in rural West and Central Africa. However, the impact of HIV infection on BU severity and prevalence remains unclear.

Methods.

 This was a retrospective study of data collected at the Akonolinga District Hospital, Cameroon, from January 1, 2002 to March 27, 2013. Human immunodeficiency virus prevalence among BU patients was compared with regional HIV prevalence. Baseline characteristics of BU patients were compared between HIV-negative and HIV-positive patients and according to CD4 cell count strata in the latter group. Buruli ulcer time-to-healing was assessed in different CD4 count strata, and factors associated with BU main lesion size at baseline were identified.

Results.

 Human immunodeficiency virus prevalence among BU patients was significantly higher than the regional estimated prevalence in each group (children, 4.00% vs 0.68% [P < .001]; men, 17.0% vs 4.7% [P < .001]; women, 36.0% vs 8.0% [P < .001]). Individuals who were HIV positive had a more severe form of BU, with an increased severity in those with a higher level of immunosuppression. Low CD4 cell count was significantly associated with a larger main lesion size (β-coefficient, −0.50; P = .015; 95% confidence interval [CI], −0.91–0.10). Buruli ulcer time-to-healing was more than double in patients with a CD4 cell count below 500 cell/mm³ (hazard ratio, 2.39; P = .001; 95% CI, 1.44–3.98).

Conclusion.

 Patients who are HIV positive are at higher risk for BU. Human immunodeficiency virus-induced immunosuppression seems to have an impact on BU clinical presentation and disease evolution.