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The American Journal of Tropical... Apr 2022Whether Mycobacterium ulcerans, the etiological agent of Buruli ulcer in numerous tropical countries, would exist in a dormant state as reported for closely related...
Whether Mycobacterium ulcerans, the etiological agent of Buruli ulcer in numerous tropical countries, would exist in a dormant state as reported for closely related Mycobacterium species, has not been established. Six M. ulcerans strains were exposed to a progressive depletion in oxygen for 2 months, using the Wayne model of dormancy previously described for M. tuberculosis, and further examined by microscopy after staining of dynamic, dormant, and dead mycobacteria (DDD staining), microcalorimetry and subculture in the presence of dead and replicative M. ulcerans as controls. Mycobacterium ulcerans CU001 strain died during the progressive oxygen depletion and four of five remaining strains exhibited Nile red-stained intracellular lipid droplets and a 14- to 20-day regrowth when exposed to ambient air, consistent with dormancy. A fifth M. ulcerans 19423 strain stained negative in DDD staining and slowly regrew in 27 days. Three tested M. ulcerans strains yielded microcalorimetric pattern similar to that of the negative (dead) homologous controls, differing from that of the homologous positive (replicative) controls. The relevance of these experimental observations, suggesting a previously unreported dormancy state of M. ulcerans, warrants further investigations in the natural ecological niches where M. ulcerans thrive as well as in Buruli ulcer lesions.
PubMed: 35405654
DOI: 10.4269/ajtmh.21-1327 -
Journal of Clinical Microbiology Mar 2020
PubMed: 32213576
DOI: 10.1128/JCM.02059-18 -
Emerging Infectious Diseases Dec 2020
Topics: Buruli Ulcer; Humans; Mycobacterium ulcerans; Skin Ulcer
PubMed: 33220026
DOI: 10.3201/eid2612.200744 -
Frontiers in Immunology 2020
Topics: Animals; Bacterial Vaccines; Glycolipids; Humans; Mycobacterium; Mycobacterium Infections
PubMed: 33133110
DOI: 10.3389/fimmu.2020.603900 -
Expert Review of Clinical Pharmacology Apr 2020Pharmacological treatment of Buruli ulcer ( infection; BU) is highly effective, as shown in two randomized trials in Africa. (Review)
Review
INTRODUCTION
Pharmacological treatment of Buruli ulcer ( infection; BU) is highly effective, as shown in two randomized trials in Africa.
AREAS COVERED
We review BU drug treatment - in vitro, in vivo and clinical trials (PubMed: '(Buruli OR (Mycobacterium AND ulcerans)) AND (treatment OR therapy).' We also highlight the pathogenesis of infection that is dominated by mycolactone, a secreted exotoxin, that causes skin and soft tissue necrosis, and impaired immune response and tissue repair. Healing is slow, due to the delayed wash-out of mycolactone. An array of repurposed tuberculosis and leprosy drugs appears effective in vitro and in animal models. In clinical trials and observational studies, only rifamycins (notably, rifampicin), macrolides (notably, clarithromycin), aminoglycosides (notably, streptomycin) and fluoroquinolones (notably, moxifloxacin, and ciprofloxacin) have been tested.
EXPERT OPINION
A combination of rifampicin and clarithromycin is highly effective but lesions still take a long time to heal. Novel drugs like telacebec have the potential to reduce treatment duration but this drug may remain unaffordable in low-resourced settings. Research should address ulcer treatment in general; essays to measure mycolactone over time hold promise to use as a readout for studies to compare drug treatment schedules for larger lesions of Buruli ulcer.
Topics: Animals; Anti-Bacterial Agents; Buruli Ulcer; Drug Repositioning; Drug Therapy, Combination; Humans; Macrolides; Mycobacterium ulcerans; Randomized Controlled Trials as Topic; Wound Healing
PubMed: 32310683
DOI: 10.1080/17512433.2020.1752663 -
Future Science OA Mar 2023is the causative agent of Buruli ulcer - a necrotizing skin infection. As an environmental pathogen, it has developed stress response mechanisms for survival. Similar... (Review)
Review
is the causative agent of Buruli ulcer - a necrotizing skin infection. As an environmental pathogen, it has developed stress response mechanisms for survival. Similar to endospore formation in , it is likely that employs sporulation mechanisms for its survival and transmission. In this review, we modeled possible transmission routes and patterns of from the environment to its host. We provided insights into the evolution of and its genomic profiles. We discuss reservoirs of as an environmental pathogen and its environmental survival. We comprehensively discuss sporulation as a possible stress response mechanism and modelled endospore formation in . At last, we highlighted sporulation associated markers, which upon expression trigger endospore formation.
PubMed: 37026027
DOI: 10.2144/fsoa-2022-0044 -
ACS Infectious Diseases Feb 2024In the recent decade, scientific communities have toiled to tackle the emerging burden of drug-resistant tuberculosis (DR-TB) and rapidly growing opportunistic... (Review)
Review
In the recent decade, scientific communities have toiled to tackle the emerging burden of drug-resistant tuberculosis (DR-TB) and rapidly growing opportunistic nontuberculous mycobacteria (NTM). Among these, two neglected mycobacteria species of the Acinetobacter family, and , are the etiological agents of leprosy and Buruli ulcer infections, respectively, and fall under the broad umbrella of neglected tropical diseases (NTDs). Unfortunately, lackluster drug discovery efforts have been made against these pathogenic bacteria in the recent decade, resulting in the discovery of only a few countable hits and majorly repurposing anti-TB drug candidates such as telacebec (Q203), P218, and TB47 for current therapeutic interventions. Major ignorance in drug candidate identification might aggravate the dramatic consequences of rapidly spreading mycobacterial NTDs in the coming days. Therefore, this Review focuses on an up-to-date account of drug discovery efforts targeting selected druggable targets from both bacilli, including the accompanying challenges that have been identified and are responsible for the slow drug discovery. Furthermore, a succinct discussion of the all-new possibilities that could be alternative solutions to mitigate the neglected mycobacterial NTD burden and subsequently accelerate the drug discovery effort is also included. We anticipate that the state-of-the-art strategies discussed here may attract major attention from the scientific community to navigate and expand the roadmap for the discovery of next-generation therapeutics against these NTDs.
Topics: Humans; Mycobacterium ulcerans; Mycobacterium leprae; Buruli Ulcer; Mycobacterium
PubMed: 38295025
DOI: 10.1021/acsinfecdis.3c00371 -
PloS One 2020Mycobacterium ulcerans is a non-tuberculous environmental mycobacterium responsible for extensive cutaneous and subcutaneous ulcers in mammals, known as Buruli ulcer in...
Mycobacterium ulcerans is a non-tuberculous environmental mycobacterium responsible for extensive cutaneous and subcutaneous ulcers in mammals, known as Buruli ulcer in humans. M. ulcerans has seldom been detected in the faeces of mammals and has not been detected in human faeces. Nevertheless, the detection and isolation of M. ulcerans in animal faeces does not fit with the current epidemiological schemes for the disease. Here, using an experimental model in which rats were fed with 109 colony-forming units of M. ulcerans, we detected M. ulcerans DNA in the faeces of challenged rats for two weeks and along their digestive tract for 10 days. M. ulcerans DNA was further detected in the lymphatic system including in the cervical and axillary lymph nodes and the spleen, but not in any other tissue including healthy and broken skin, 10 days post-challenge. These observations indicate that in some herbivorous mammals, M. ulcerans contamination by the digestive route may precede translocation and limited contamination of the lymphatic tissues without systemic infection. These herbivorous mammals may be sources of M. ulcerans for exposed populations but are unlikely to be reservoirs for the pathogen.
Topics: Animals; DNA, Bacterial; Feces; Gastrointestinal Tract; Mycobacterium Infections, Nontuberculous; Mycobacterium ulcerans; Rats; Rats, Long-Evans
PubMed: 33378325
DOI: 10.1371/journal.pone.0230544 -
Microorganisms Jul 2022Nontuberculous mycobacteria (NTM) represent an important group of environmentally saprophytic and potentially pathogenic bacteria that can cause serious mycobacterioses...
Nontuberculous mycobacteria (NTM) represent an important group of environmentally saprophytic and potentially pathogenic bacteria that can cause serious mycobacterioses in humans and animals. The sources of infections often remain undetected except for soil- or water-borne, water-washed, water-based, or water-related infections caused by groups of the complex; and other NTM species, including infection, known as fish tank granuloma, and infection, which is described as a Buruli ulcer. NTM could be considered as water-borne, air-borne, and soil-borne pathogens (sapronoses). A lot of clinically relevant NTM species could be considered due to the enormity of published data on permanent, periodic, transient, and incidental sapronoses. Interest is currently increasing in mycobacterioses diagnosed in humans and husbandry animals (esp. pigs) caused by NTM species present in peat bogs, potting soil, garden peat, bat and bird guano, and other matrices used as garden fertilizers. NTM are present in dust particles and in water aerosols, which represent certain factors during aerogenous infection in immunosuppressed host organisms during hospitalization, speleotherapy, and leisure activities. For this Special Issue, a collection of articles providing a current view of the research on NTM-including the clinical relevance, therapy, prevention of mycobacterioses, epidemiology, and ecology-are addressed.
PubMed: 35893574
DOI: 10.3390/microorganisms10081516