| Mycobacterium ulcerans | |
|---|---|
 | |
Scientific classification | |
| Domain: | Bacteria |
| Kingdom: | Bacillati |
| Phylum: | Actinomycetota |
| Class: | Actinomycetia |
| Order: | Mycobacteriales |
| Family: | Mycobacteriaceae |
| Genus: | Mycobacterium |
| Species: | M. ulcerans |
| Binomial name | |
| Mycobacterium ulcerans MacCallumet al., 1950 | |
Mycobacterium ulcerans is a species of bacteria found in various aquatic environments. The bacteria can infect humans and some other animals, causing persistent open wounds calledBuruli ulcer.M. ulcerans is closely related toMycobacterium marinum, from which it evolved around one million years ago, and more distantly to themycobacteria which causetuberculosis andleprosy.
Mycobacterium ulcerans arerod-shaped bacteria.[1] They appear purple ("Gram positive") underGram stain and bright red ("acid fast") underZiehl–Neelsen stain.[1] On laboratorymedia,M. ulcerans grow slowly, forming small transparentcolonies after four weeks.[1] As colonies age, they develop irregular outlines and a rough, yellow surface.[1] The bacteria was discovered by Australian scientistsJean Tolhurst and Glen Buckle in the late 1940s.
Mycobacterium ulcerans is a species ofmycobacteria within the phylumActinomycetota. Within the genusMycobacterium,M. ulcerans is classified as both a "non-tuberculous mycobacterium" and a "slow-growing mycobacterium".[2]
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| A cladogram showing the relationships among the mycobacteria that cause disease in humans.[3] |
M. ulcerans likely evolved from the closely related aquatic pathogenMycobacterium marinum around one million years ago.[4] The two species are genetically very similar, and have identical16S ribosomal RNA genes.[1] However relative toM. marinum,M. ulcerans has undergone substantialgenome reduction, shedding over a thousandkilobases of genetic content including nearly 1300 genes (23% of the totalM. marinum genes) and sustaining theinactivation of an additional 700 genes.[5] Some of these genes were inactivated by the proliferation of twomobile genetic elements, called "IS2404" (213 copies) and "IS2606" (91 copies), neither of which are present inM. marinum.[5] Additionally,M. ulcerans has acquired a 174 kilobaseplasmid, termed "pMUM001", which is involved in the production of the toxinmycolactone.[5] Other closely related mycobacteria produce mycolactone and infect various aquatic animals; these are sometimes described as distinct species (M. pseudoshottsii,M. liflandii,M. shinshuense and sometimesM. marinum) and sometimes as different lineages ofM. ulcerans. Regardless, all mycolactone-producing mycobacteria share a common ancestor distinct from non-mycolactone-producingM. marinum.[6]
