Challenges associated with the treatment of Buruli ulcer

Bacterial diversity in Buruli ulcer lesions in Ghana

Background

Previous studies have demonstrated secondary microbial infection of Buruli ulcer (BUD) lesions before, during and after treatment. However, there is limited data on the bacterial diversity across treatment and their influence on clinical outcome. The present study aimed to investigate the relationship between bacterial diversity within BUD lesions and clinical outcome in affected individuals.

Methods

We investigated the bacterial diversity within lesions of individuals with PCR confirmed BUD from 5 endemic districts within central Ghana. Samples were collected longitudinally from lesions over treatment period. Microbiological analyses including isolation of bacteria, and species identification were performed using the VITEK 2 compact.

Results

Out of 36 participants included, 80.5 % presented with ulcers on the lower limbs. Higher bacterial diversity was observed in ulcers compared to other clinical forms of BUD. There was a significant association between bacterial diversity and clinical outcome (p = 0.002). ESBL producing bacteria and MRSA were isolated in slow healing BUD lesions.

Conclusion

Higher diversity of secondary organisms colonizing BUD lesions may have an impact on clinical outcome in affected individuals. There is the need for the development of treatment guidelines for simultaneous management of M. ulcerans and other potential pathogens within lesions to improve clinical outcome.

Formulation and Stability of a 1% Clarithromycin-Based Topical Skin Cream: A New Option to Treat Buruli Ulcers?

There are more than 170 known species of non-tuberculous mycobacteria, and some are responsible for serious diseases in people infected with them. One of these is Buruli ulcers, a neglected tropical disease endemic in more than 33 countries and caused by Mycobacterium ulcerans, which infects skin tissue. Treatment consists of a long-term regimen combining the use of oral rifampin with another anti-tuberculosis drug (e.g., clarithromycin). Patients in these countries face difficulties in accessing and adhering to this therapy. This study investigates the feasibility of formulating stable, optimized clarithromycin as a topical cutaneous cream. The cream was formulated, and its stability was evaluated under different storage temperature conditions and using a stability indicator method. The results showed that the clarithromycin cream was stable for at least 60 days, even at extreme temperatures (40 °C). In conclusion, the data presented here demonstrate the stability of a new form of topical cutaneous clarithromycin, which may offer a new approach to the treatment of Buruli ulcers and clarithromycin-sensitive infections.

A review of chemical signaling mechanisms underlying quorum sensing and its inhibition in Staphylococcus aureus

Staphylococcus aureus is a significant bacterium responsible for multiple infections and is a primary cause of fatalities among patients in hospital environments. The advent of pathogenic bacteria such as methicillin-resistant S. aureus revealed the shortcomings of employing antibiotics to treat bacterial infectious diseases. Quorum sensing enhances S. aureus's survivability through signaling processes. Targeting the key components of quorum sensing has drawn much interest nowadays as a promising strategy for combating infections caused by bacteria. Concentrating on the accessory gene regulator quorum-sensing mechanism is the most commonly suggested anti-virulence approach for S.aureus. Quorum quenching is a common strategy for controlling illnesses triggered by microorganisms since it reduces the pathogenicity of bacteria and improves bacterial biofilm susceptibility to antibiotics, thus providing an intriguing prospect for drug discovery. Quorum sensing inhibition reduces selective stresses and constrains the emergence of antibiotic resistance while limiting bacterial pathogenicity. This review examines the quorum sensing mechanisms involved in S. aureus, quorum sensing targets and gene regulation, environmental factors affecting quorum sensing, quorum sensing inhibition, natural products as quorum sensing inhibitory agents and novel therapeutical strategies to target quorum sensing in S. aureus as drug developing technique to augment conventional antibiotic approaches.

Clinical and microbiological predictors of healing in Buruli ulcer disease

Introduction

Wound measurements are relevant in monitoring the rate of healing (RoH) and may predict time to healing. Predicting the time to healing can help improve the management of Buruli ulcer. We examine three methods for the determination of RoH and their use as predictors of time to healing.

Methods

Lesion measurements of Buruli ulcer patients treated from 2007 to 2022 were obtained with acetate sheet tracings (2D) or Aranz software (3D) fortnightly. RoH was determined using the absolute area, percentage area reduction and linear methods at 4 weeks post onset of antibiotic treatment. Predicted time to healing was compared to the actual healing time. Baseline characteristics were assessed for associations with healing.

Results

All three methods for calculating the RoH significantly distinguished between fast and slow healers (p < 0.0001). The predicted healing time using the linear method was comparable to the actual healing time for fast healers (p = 0.34). The RoH was influenced by the form of lesion, with plaques [OR 2.19 5 %CI (1.2-3.6), p = 0.009], and oedemas [OR 8.5; 95 %CI (1.9--36.9), p = 0.004] being associated with delayed healing. The proportion of patients with paradoxical reactions 16 % vs 3 %, p < 0.0001), higher baseline bacterial load (75/104;72 % vs 21/47;45 %, p = 0.001) and delayed clearance of viable organisms (71/104;68 % vs 9/47;19 %, p < 0.0001) was higher in the slow healers than the fast healers.

Conclusion

Predicted healing rates were comparatively lower for slow healers than fast healers. Baseline characteristics associated with healing can be explored for an improved disease management plan to reduce patient and caregiver anxiety.

Identification of potential candidate vaccines against Mycobacterium ulcerans based on the major facilitator superfamily transporter protein

Buruli ulcer is a neglected tropical disease that is characterized by non-fatal lesion development. The causative agent is Mycobacterium ulcerans (M. ulcerans). There are no known vectors or transmission methods, preventing the development of control methods. There are effective diagnostic techniques and treatment routines; however, several socioeconomic factors may limit patients' abilities to receive these treatments. The Bacillus Calmette-Guérin vaccine developed against tuberculosis has shown limited efficacy, and no conventionally designed vaccines have passed clinical trials. This study aimed to generate a multi-epitope vaccine against M. ulcerans from the major facilitator superfamily transporter protein using an immunoinformatics approach. Twelve M. ulcerans genome assemblies were analyzed, resulting in the identification of 11 CD8+ and 7 CD4+ T-cell epitopes and 2 B-cell epitopes. These conserved epitopes were computationally predicted to be antigenic, immunogenic, non-allergenic, and non-toxic. The CD4+ T-cell epitopes were capable of inducing interferon-gamma and interleukin-4. They successfully bound to their respective human leukocyte antigens alleles in in silico docking studies. The expected global population coverage of the T-cell epitopes and their restricted human leukocyte antigens alleles was 99.90%. The population coverage of endemic regions ranged from 99.99% (Papua New Guinea) to 21.81% (Liberia). Two vaccine constructs were generated using the Toll-like receptors 2 and 4 agonists, LprG and RpfE, respectively. Both constructs were antigenic, non-allergenic, non-toxic, thermostable, basic, and hydrophilic. The DNA sequences of the vaccine constructs underwent optimization and were successfully in-silico cloned with the pET-28a(+) plasmid. The vaccine constructs were successfully docked to their respective toll-like receptors. Molecular dynamics simulations were carried out to analyze the binding interactions within the complex. The generated binding energies indicate the stability of both complexes. The constructs generated in this study display severable favorable properties, with construct one displaying a greater range of favorable properties. However, further analysis and laboratory validation are required.

Beyond the approved: target sites and inhibitors of bacterial RNA polymerase from bacteria and fungi

Covering: 2016 to 2022RNA polymerase (RNAP) is the central enzyme in bacterial gene expression representing an attractive and validated target for antibiotics. Two well-known and clinically approved classes of natural product RNAP inhibitors are the rifamycins and the fidaxomycins. Rifampicin (Rif), a semi-synthetic derivative of rifamycin, plays a crucial role as a first line antibiotic in the treatment of tuberculosis and a broad range of bacterial infections. However, more and more pathogens such as Mycobacterium tuberculosis develop resistance, not only against Rif and other RNAP inhibitors. To overcome this problem, novel RNAP inhibitors exhibiting different target sites are urgently needed. This review includes recent developments published between 2016 and today. Particular focus is placed on novel findings concerning already known bacterial RNAP inhibitors, the characterization and development of new compounds isolated from bacteria and fungi, and providing brief insights into promising new synthetic compounds.

The search for a Buruli Ulcer vaccine and the effectiveness of the Bacillus Calmette-Guérin vaccine

Buruli Ulcer is a neglected tropical disease that is caused by Mycobacterium ulcerans. It is not fatal; however, it manifests a range of devastating symptoms on the hosts' bodies. Various drugs and treatments are available for the disease; however, they are often costly and have adverse effects. There is still much uncertainty regarding the mode of transmission, vectors, and reservoir. At present, there are no official vector control methods, prevention methods, or a vaccine licensed to prevent infection. The Bacillus Calmette-Guérin vaccine developed against tuberculosis has some effectiveness against M. ulcerans. However, it is unable to induce long-lasting protection. Various types of vaccines have been developed based specifically against M. ulcerans; however, to date, none has entered clinical trials or has been released for public use. Additional awareness and funding are needed for research in this field and the development of more treatments, diagnostic tools, and vaccines.

Experiences of Buruli Ulcer Patients Following Discharge in the Greater Accra Region of Ghana

Buruli ulcer (BU) is one of the skin diseases that causes physical deformity, loss of function of the affected part, social stigmatization, and financial burden to individuals affected. Annually, an approximated 6000 cases of BU are reported worldwide especially from West Africa, Central Africa, and Asia. The aim of the study was to assess the experiences of BU patients in the Greater Accra Region of Ghana following discharge from the hospital. The study employed a qualitative descriptive phenomenological approach using snowballing sampling technique to sample 15 participants from the Greater Accra Region of Ghana who have been treated and discharged home. Data were collected through face-to-face interviews that was later transcribed and coded using qualitative content analysis. Findings from this study revealed that individuals with BU goes through several challenges during admission and after discharge including feeling of embarrassment, financially handicapped, and marital conflicts. The study concluded that BU has not been totally eradicated from the country, hence must be given the attention it deserves to help individuals cope better.

Barriers to Buruli ulcer treatment completion in the Ashanti and Central Regions, Ghana

BACKGROUND

Buruli ulcer is a chronic ulcerating skin condition, with the highest burden found in Central and West Africa where it disproportionately affects the most vulnerable populations. Treatment is demanding, comprising eight-weeks of daily antibiotics, regular wound care and possible surgical intervention. Treatment completion is key to optimising outcomes, however the degree of and barriers to this are not well understood. Recent change from injectable treatment (SR8) to oral treatment (CR8) has made it feasible to further decentralise care, potentially improving treatment access and completion. However, the impact of this and of other demographic and clinical influences on treatment completion must be explored first to ensure appropriate models of care are developed.

METHODOLOGY/PRINCIPAL FINDINGS

A retrospective clinical notes review and secondary data analysis of records from patients diagnosed between 1 January 2006-31 December 2018 at four district hospital clinics in the Ashanti and Central Regions, Ghana. Univariable analyses and multivariable logistic regression were performed to assess the association between explanatory variables and treatment completion. There were 931 patient episodes across the four clinics with overall treatment completion of 84.4%. CR8 was associated with higher treatment completion compared to SR8 (OR 4.1, P = 0.001). There was no statistically significant association found between distance from patient residence to clinic and treatment completion.

CONCLUSIONS/SIGNIFICANCE

Improved treatment completion with CR8 supports its use as first line therapy and may enable decentralisation to fully community-based care. We did not find an association between distance to care and treatment completion, though analyses were limited by data availability. However, we did find evidence that distance to care continues to be associated with more severe forms of disease, which may reflect the higher costs of accessing care and lower awareness of the condition the further a patient lives. Decentralised care must therefore also continue to support community engagement and active outreach to identify cases early.

Progress and history of the 10th Federation of African Immunological Societies Congress

The 10th Federation of African Immunological Societies (FAIS) Congress, held in Tunisia in November 2017, marked a significant scientific milestone. It enabled scientists from across the continent to promote immunology research and to showcase major achievements made by immunologists throughout Africa. This issue of the Journal of Leukocyte Biology (JLB) features manuscripts from the FAIS Congress. As noted in these papers, research in infectious diseases remains the focus of the African immunology community; however, increasingly noncommunicable diseases-such as autoimmunity, allergy, primary immunodeficiency, cancer and transplantation immunology-are also an emerging priority. This overview gives a brief history of the FAIS meeting, which also commemorated the 25th anniversary of the FAIS. It describes the current activities of the organization, as well as its history and the future opportunities for this Federation.