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Scientific Reports Feb 2021Mycobacterium ulcerans secrete a series of non-ribosomal-encoded toxins known as mycolactones that are responsible for causing a disabling ulceration of the skin and...
Mycobacterium ulcerans secrete a series of non-ribosomal-encoded toxins known as mycolactones that are responsible for causing a disabling ulceration of the skin and subcutaneous tissues named Buruli ulcer. The disease is the sole non-contagion among the three most common mycobacterial diseases in humans. Direct contact with contaminated wetlands is a risk factor for Buruli ulcer, responsible for M. ulcerans skin carriage before transcutaneous inoculation with this opportunistic pathogen. In this study, we analysed the bacterial and fungal skin microbiota in individuals exposed to M. ulcerans in Burkina Faso. We showed that M. ulcerans-specific DNA sequences were detected on the unbreached skin of 6/52 (11.5%) asymptomatic farmers living in Sindou versus 0/52 (0%) of those living in the non-endemic region of Tenkodogo. Then, we cultured the skin microbiota of asymptomatic M. ulcerans carriers and negative control individuals, all living in the region of Sindou. A total of 84 different bacterial and fungal species were isolated, 21 from M. ulcerans-negative skin samples, 31 from M. ulcerans-positive samples and 32 from both. More specifically, Actinobacteria, Aspergillus niger and Aspergillus flavus were significantly associated with M. ulcerans skin carriage. We further observed that in vitro, mycolactones induced spore germination of A. flavus, attracting the fungal network. These unprecedented observations suggest that interactions with fungi may modulate the outcome of M. ulcerans skin carriage, opening new venues to the understanding of Buruli ulcer pathology, prophylaxis and treatment of this still neglected tropical infection.
Topics: Aspergillosis; Aspergillus; Burkina Faso; Buruli Ulcer; DNA, Bacterial; Fungi; Humans; Microbiota; Mycobacterium ulcerans; Skin
PubMed: 33580189
DOI: 10.1038/s41598-021-83236-7 -
PLoS Pathogens Sep 2009Mycobacterium ulcerans is the causative agent of Buruli ulcer, the third most common mycobacterial disease after tuberculosis and leprosy. It is an emerging infectious...
Mycobacterium ulcerans is the causative agent of Buruli ulcer, the third most common mycobacterial disease after tuberculosis and leprosy. It is an emerging infectious disease that afflicts mainly children and youths in West Africa. Little is known about the evolution and transmission mode of M. ulcerans, partially due to the lack of known genetic polymorphisms among isolates, limiting the application of genetic epidemiology. To systematically profile single nucleotide polymorphisms (SNPs), we sequenced the genomes of three M. ulcerans strains using 454 and Solexa technologies. Comparison with the reference genome of the Ghanaian classical lineage isolate Agy99 revealed 26,564 SNPs in a Japanese strain representing the ancestral lineage. Only 173 SNPs were found when comparing Agy99 with two other Ghanaian isolates, which belong to the two other types previously distinguished in Ghana by variable number tandem repeat typing. We further analyzed a collection of Ghanaian strains using the SNPs discovered. With 68 SNP loci, we were able to differentiate 54 strains into 13 distinct SNP haplotypes. The average SNP nucleotide diversity was low (average 0.06-0.09 across 68 SNP loci), and 96% of the SNP locus pairs were in complete linkage disequilibrium. We estimated that the divergence of the M. ulcerans Ghanaian clade from the Japanese strain occurred 394 to 529 thousand years ago. The Ghanaian subtypes diverged about 1000 to 3000 years ago, or even much more recently, because we found evidence that they evolved significantly faster than average. Our results offer significant insight into the evolution of M. ulcerans and provide a comprehensive report on genetic diversity within a highly clonal M. ulcerans population from a Buruli ulcer endemic region, which can facilitate further epidemiological studies of this pathogen through the development of high-resolution tools.
Topics: Buruli Ulcer; Evolution, Molecular; Genes, Bacterial; Genetic Variation; Genome, Bacterial; Ghana; Humans; Linkage Disequilibrium; Molecular Epidemiology; Mycobacterium ulcerans; Phylogeny; Polymorphism, Single Nucleotide; Reproducibility of Results; Sequence Analysis, DNA
PubMed: 19806175
DOI: 10.1371/journal.ppat.1000580 -
PLoS Neglected Tropical Diseases Dec 2015The clinical presentation of M. ulcerans disease and the safety and effectiveness of treatment may differ in elderly compared with younger populations related to... (Observational Study)
Observational Study
BACKGROUND
The clinical presentation of M. ulcerans disease and the safety and effectiveness of treatment may differ in elderly compared with younger populations related to relative immune defficiencies, co-morbidities and drug interactions. However, elderly populations with M. ulcerans disease have not been comprehensively studied.
METHODOLOGY/PRINCIPAL FINDINGS
A retrospective analysis was performed on an observational cohort of all confirmed M. ulcerans cases managed at Barwon Health from 1/1/1998-31/12/2014. The cohort included 327 patients; 131(40.0%) ≥65 years and 196(60.0%) <65 years of age. Patients ≥65 years had a shorter median duration of symptoms prior to diagnosis (p<0.01), a higher proportion with diabetes (p<0.001) and immune suppression (p<0.001), and were more likely to have lesions that were multiple (OR 4.67, 95% CI 1.78-12.31, p<0.001) and WHO category 3 (OR 4.59, 95% CI 1.98-10.59, p<0.001). Antibiotic complications occurred in 69(24.3%) treatment episodes at an increased incidence in those aged ≥65 years (OR 5.29, 95% CI 2.81-9.98, p<0.001). There were 4(1.2%) deaths, with significantly more in the age-group ≥65 years (4 compared with 0 deaths, p = 0.01). The overall treatment success rate was 92.2%. For the age-group ≥65 years there was a reduced rate of treatment success overall (OR 0.34, 95% CI 0.14-0.80, p = <0.01) and when surgery was used alone (OR 0.21, 95% CI 0.06-0.76, p<0.01). Patients ≥65 years were more likely to have a paradoxical reaction (OR 2.06, 95% CI 1.17-3.62, p = 0.01).
CONCLUSIONS/SIGNIFICANCE
Elderly patients comprise a significant proportion of M. ulcerans disease patients in Australian populations and present with more severe and advanced disease forms. Currently recommended treatments are associated with increased toxicity and reduced effectiveness in elderly populations. Increased efforts are required to diagnose M. ulcerans earlier in elderly populations, and research is urgently required to develop more effective and less toxic treatments for this age-group.
Topics: Adult; Aged; Anti-Bacterial Agents; Australia; Buruli Ulcer; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Male; Middle Aged; Mycobacterium ulcerans; Retrospective Studies; Survival Analysis; Treatment Outcome
PubMed: 26630648
DOI: 10.1371/journal.pntd.0004253 -
PLoS Neglected Tropical Diseases Jul 2021Nontuberculosis mycobacterial (NTM) infections are increasing in prevalence across the world. In many cases, treatment options for these infections are limited. However,...
Nontuberculosis mycobacterial (NTM) infections are increasing in prevalence across the world. In many cases, treatment options for these infections are limited. However, there has been progress in recent years in the development of new antimycobacterial drugs. Here, we investigate the in vitro activity of SPR719, a novel aminobenzimidazole antibiotic and the active form of the clinical-stage compound, SPR720, against several isolates of Mycobacterium ulcerans, Mycobacterium marinum and Mycobacterium chimaera. We show that SPR719 is active against these NTM species with a MIC range of 0.125-4 μg/ml and that this compares favorably with the commonly utilized antimycobacterial antibiotics, rifampicin and clarithromycin. Our findings suggest that SPR720 should be further evaluated for the treatment of NTM infections.
Topics: Anti-Bacterial Agents; DNA Gyrase; Drug Resistance, Bacterial; Gene Expression Regulation, Bacterial; Mutation; Mycobacterium; Mycobacterium marinum; Mycobacterium ulcerans
PubMed: 34310615
DOI: 10.1371/journal.pntd.0009636 -
Methods in Molecular Biology (Clifton,... 2022As acknowledged by the Clinical and Laboratory Standards Institute (CLSI), there is an insufficient evidence base on which to recommend a standard method for...
As acknowledged by the Clinical and Laboratory Standards Institute (CLSI), there is an insufficient evidence base on which to recommend a standard method for antimicrobial susceptibility testing against M. ulcerans. The agar proportion method has been recognized as the standard method for susceptibility testing against Mycobacterium tuberculosis complex (MTBC) isolates for decades (Woods GL, Engenack NL, Lin G, Turnidge JD (2018) CLSI standards: guidelines for health care excellence. Susceptibility testing of mycobacteria, Nocardia spp., and other aerobic Actinomycetes, 3rd edn. Clinical and Laboratory Standards Institute Copyright©2018 Clinical and Laboratory Standards Institute, Wayne (PA)). While it is more labor-intensive and requires larger amounts of drug or compound than broth-based testing, we recommend the agar proportion method for determination of minimum inhibitory concentrations against M. ulcerans. Herewith we present the method we implemented in our laboratory over the last 2 decades.
Topics: Agar; Anti-Bacterial Agents; Microbial Sensitivity Tests; Mycobacterium ulcerans; Pharmaceutical Preparations
PubMed: 34643913
DOI: 10.1007/978-1-0716-1779-3_18 -
Microbiology Spectrum Jun 2023Mycobacterium ulcerans, an environmental opportunistic pathogen, causes necrotic cutaneous and subcutaneous lesions, named Buruli ulcers, in tropical countries....
Mycobacterium ulcerans, an environmental opportunistic pathogen, causes necrotic cutaneous and subcutaneous lesions, named Buruli ulcers, in tropical countries. PCR-derived tests used to detect M. ulcerans in environmental and clinical samples do not allow one-shot detection, identification, and typing of M. ulcerans among closely related Mycobacterium marinum complex mycobacteria. We established a 385-member M. marinum/M. ulcerans complex whole-genome sequence database by assembling and annotating 341 M. marinum/M. ulcerans complex genomes and added 44 M. marinum/M. ulcerans complex whole-genome sequences already deposited in the NCBI database. Pangenome, core genome, and single-nucleotide polymorphism (SNP) distance-based comparisons sorted the 385 strains into 10 M. ulcerans taxa and 13 M. marinum taxa, correlating with the geographic origin of strains. Aligning conserved genes identified one (proline-proline-glutamate) gene sequence to be species and intraspecies specific, thereby genotyping the 23 M. marinum/M. ulcerans complex taxa. PCR sequencing of the gene correctly genotyped nine M. marinum/M. ulcerans complex isolates among one M. marinum taxon and three M. ulcerans taxa in the African taxon (T2.4). Further, successful gene PCR sequencing in 15/21 (71.4%) swabs collected from suspected Buruli ulcer lesions in Côte d'Ivoire exhibited positive M. ulcerans 2404 real-time PCR and identified the M. ulcerans T2.4.1 genotype in eight swabs and M. ulcerans T2.4.1/T2.4.2 mixed genotypes in seven swabs. gene sequencing could be used as a proxy for whole-genome sequencing for the one-shot detection, identification, and typing of clinical M. ulcerans strains, offering an unprecedented tool for identifying M. ulcerans mixed infections. We describe a new targeted sequencing approach that characterizes the gene to disclose the simultaneous presence of different variants of a single pathogenic microorganism. This approach has direct implications on the understanding of pathogen diversity and natural history and potential therapeutic implications when dealing with obligate and opportunistic pathogens, such as Mycobacterium ulcerans presented here as a prototype.
Topics: Humans; Buruli Ulcer; Mycobacterium ulcerans; Cote d'Ivoire; Real-Time Polymerase Chain Reaction; Personal Protective Equipment
PubMed: 37222600
DOI: 10.1128/spectrum.00342-23 -
Clinical Microbiology Reviews Jan 2018Buruli ulcer is a noncontagious disabling cutaneous and subcutaneous mycobacteriosis reported by 33 countries in Africa, Asia, Oceania, and South America. The causative... (Review)
Review
Buruli ulcer is a noncontagious disabling cutaneous and subcutaneous mycobacteriosis reported by 33 countries in Africa, Asia, Oceania, and South America. The causative agent, , derives from by genomic reduction and acquisition of a plasmid-borne, nonribosomal cytotoxin mycolactone, the major virulence factor. -specific sequences have been readily detected in aquatic environments in food chains involving small mammals. Skin contamination combined with any type of puncture, including insect bites, is the most plausible route of transmission, and skin temperature of <30°C significantly correlates with the topography of lesions. After 30 years of emergence and increasing prevalence between 1970 and 2010, mainly in Africa, factors related to ongoing decreasing prevalence in the same countries remain unexplained. Rapid diagnosis, including laboratory confirmation at the point of care, is mandatory in order to reduce delays in effective treatment. Parenteral and potentially toxic streptomycin-rifampin is to be replaced by oral clarithromycin or fluoroquinolone combined with rifampin. In the absence of proven effective primary prevention, avoiding skin contamination by means of clothing can be implemented in areas of endemicity. Buruli ulcer is a prototype of ecosystem pathology, illustrating the impact of human activities on the environment as a source for emerging tropical infectious diseases.
Topics: Anti-Infective Agents; Buruli Ulcer; Ecosystem; Humans; Mycobacterium ulcerans
PubMed: 29237707
DOI: 10.1128/CMR.00045-17 -
PloS One 2023Mycolactone is a cytotoxic lipid metabolite produced by Mycobacterium ulcerans, the environmental pathogen responsible for Buruli ulcer, a neglected tropical disease....
Mycolactone is a cytotoxic lipid metabolite produced by Mycobacterium ulcerans, the environmental pathogen responsible for Buruli ulcer, a neglected tropical disease. Mycobacterium ulcerans is prevalent in West Africa, particularly found in lentic environments, where mosquitoes also occur. Researchers hypothesize mosquitoes could serve as a transmission mechanism resulting in infection by M. ulcerans when mosquitoes pierce skin contaminated with M. ulcerans. The interplay between the pathogen, mycolactone, and mosquito is only just beginning to be explored. A triple-choice assay was conducted to determine the host-seeking preference of Aedes aegypti between M. ulcerans wildtype (MU, mycolactone active) and mutant (MUlac-, mycolactone inactive). Both qualitative and quantitative differences in volatile organic compounds' (VOCs) profiles of MU and MUlac- were determined by GC-MS. Additionally, we evaluated the interplay between Ae. aegypti proximity and M. ulcerans mRNA expression. The results showed that mosquito attraction was significantly greater (126.0%) to an artificial host treated with MU than MUlac-. We found that MU and MUlac produced differential profiles of VOCs associated with a wide range of biological importance from quorum sensing (QS) to human odor components. RT-qPCR assays showed that mycolactone upregulation was 24-fold greater for MU exposed to Ae. aegypti in direct proximity. Transcriptome data indicated significant induction of ten chromosomal genes of MU involved in stress responses and membrane protein, compared to MUlac- when directly having access to or in near mosquito proximity. Our study provides evidence of possible interkingdom interactions between unicellular and multicellular species that MU present on human skin is capable of interreacting with unrelated species (i.e., mosquitoes), altering its gene expression when mosquitoes are in direct contact or proximity, potentially impacting the production of its VOCs, and consequently leading to the stronger attraction of mosquitoes toward human hosts. This study elucidates interkingdom interactions between viable M. ulcerans bacteria and Ae. aegypti mosquitoes, which rarely have been explored in the past. Our finding opens new doors for future research in terms of disease ecology, prevalence, and pathogen dispersal outside of the M. ulcerans system.
Topics: Animals; Humans; Mycobacterium ulcerans; Buruli Ulcer; Macrolides; Aedes; Gene Expression
PubMed: 37535670
DOI: 10.1371/journal.pone.0289768 -
PLoS Neglected Tropical Diseases May 2014Mycobacterium ulcerans (MU) is the agent responsible for Buruli Ulcer (BU), an emerging skin disease with dramatic socioeconomic and health outcomes, especially in rural...
Mycobacterium ulcerans ecological dynamics and its association with freshwater ecosystems and aquatic communities: results from a 12-month environmental survey in Cameroon.
BACKGROUND
Mycobacterium ulcerans (MU) is the agent responsible for Buruli Ulcer (BU), an emerging skin disease with dramatic socioeconomic and health outcomes, especially in rural settings. BU emergence and distribution is linked to aquatic ecosystems in tropical and subtropical countries, especially to swampy and flooded areas. Aquatic animal organisms are likely to play a role either as host reservoirs or vectors of the bacilli. However, information on MU ecological dynamics, both in space and time, is dramatically lacking. As a result, the ecology of the disease agent, and consequently its mode of transmission, remains largely unknown, which jeopardizes public health attempts for its control. The objective of this study was to gain insight on MU environmental distribution and colonization of aquatic organisms through time.
METHODOLOGY/PRINCIPAL FINDINGS
Longitudinal sampling of 32 communities of aquatic macro-invertebrates and vertebrates was conducted from different environments in two BU endemic regions in Cameroon during 12 months. As a result, 238,496 individuals were classified and MU presence was assessed by qPCR in 3,084 sample-pools containing these aquatic organisms. Our study showed a broad distribution of MU in all ecosystems and taxonomic groups, with important regional differences in its occurrence. Colonization dynamics fluctuated along the year, with the highest peaks in August and October. The large variations observed in the colonization dynamics of different taxonomic groups and aquatic ecosystems suggest that the trends shown here are the result of complex ecological processes that need further investigation.
CONCLUSION/PERSPECTIVES
This is the largest field study on MU ecology to date, providing the first detailed description of its spatio-temporal dynamics in different aquatic ecosystems within BU endemic regions. We argue that coupling this data with fine-scale epidemiological data through statistical and mathematical models will provide a major step forward in the understanding of MU ecology and mode of transmission.
Topics: Animals; Aquatic Organisms; Buruli Ulcer; Cameroon; DNA, Bacterial; Ecosystem; Fresh Water; Invertebrates; Mycobacterium ulcerans; Polymerase Chain Reaction; Spatio-Temporal Analysis; Water Microbiology
PubMed: 24831924
DOI: 10.1371/journal.pntd.0002879 -
Toxins May 2023"Recognizing a surprising fact is the first step towards discovery." This famous quote from Louis Pasteur is particularly appropriate to describe what led us to study... (Review)
Review
"Recognizing a surprising fact is the first step towards discovery." This famous quote from Louis Pasteur is particularly appropriate to describe what led us to study mycolactone, a lipid toxin produced by the human pathogen . is the causative agent of Buruli ulcer, a neglected tropical disease manifesting as chronic, necrotic skin lesions with a "surprising" lack of inflammation and pain. Decades after its first description, mycolactone has become much more than a mycobacterial toxin. This uniquely potent inhibitor of the mammalian translocon (Sec61) helped reveal the central importance of Sec61 activity for immune cell functions, the spread of viral particles and, unexpectedly, the viability of certain cancer cells. We report in this review the main discoveries that marked our research into mycolactone, and the medical perspectives they opened up. The story of mycolactone is not over and the applications of Sec61 inhibition may go well beyond immunomodulation, viral infections, and oncology.
Topics: Animals; Humans; Buruli Ulcer; Mycobacterium ulcerans; Macrolides; Bacterial Toxins; Mammals
PubMed: 37368670
DOI: 10.3390/toxins15060369