Mycobacterium ulcerans: Difference between revisions

Latest revision as of 16:30, 16 February 2025

Mycobacterium ulcerans[edit]

Mycobacterium ulcerans is a slow-growing bacterium that is the causative agent of Buruli ulcer, a chronic debilitating skin and soft tissue infection. This organism is part of the Mycobacterium genus, which also includes the pathogens responsible for tuberculosis and leprosy.

Characteristics[edit]

Mycobacterium ulcerans is an acid-fast bacillus, meaning it retains certain dyes after being washed with acidic solutions. This characteristic is shared with other mycobacteria. The bacterium grows optimally at temperatures between 29°C and 33°C, which is lower than the body temperature of humans, explaining its predilection for cooler areas of the body such as the skin.

Pathogenesis[edit]

The pathogenesis of Mycobacterium ulcerans is primarily due to the production of a toxin called mycolactone. Mycolactone is a polyketide-derived macrolide that causes tissue necrosis and immunosuppression. The toxin's effects lead to the characteristic ulcers seen in Buruli ulcer disease.

Epidemiology[edit]

Buruli ulcer is most commonly found in rural areas of West Africa, but cases have been reported in over 30 countries worldwide, including regions in Australia, Southeast Asia, and South America. The exact mode of transmission of Mycobacterium ulcerans is not fully understood, but it is believed to be associated with aquatic environments.

Clinical Presentation[edit]

The disease typically begins as a painless nodule or papule, which can progress to a large ulcer with undermined edges. The ulceration is often painless, which can delay diagnosis and treatment. If left untreated, Buruli ulcer can lead to significant morbidity, including scarring and contractures.

Diagnosis[edit]

Diagnosis of Mycobacterium ulcerans infection is primarily clinical, supported by laboratory tests such as polymerase chain reaction (PCR) to detect mycobacterial DNA, microscopy of stained smears, and culture of the organism from tissue samples.

Treatment[edit]

Treatment of Buruli ulcer involves a combination of antibiotics, typically rifampicin and clarithromycin or streptomycin, for a period of 8 weeks. Surgical intervention may be necessary for extensive lesions to remove necrotic tissue and promote healing.

Related pages[edit]

Template:Mycobacterium

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-'''Mycobacterium ulcerans''' is a species of bacteria from the [[Mycobacterium]] genus, which is responsible for causing [[Buruli ulcer]], a chronic, debilitating skin and soft tissue infection. This bacterium is an environmental pathogen found in specific aquatic environments, such as slow-moving water, swamps, and wetlands, primarily in tropical and subtropical regions. The mode of transmission to humans remains partially understood, but it is believed to involve direct contact with contaminated water or soil.
+== Mycobacterium ulcerans ==
-==Characteristics==
+[[File:Buruli_ulcer_traveler.png|thumb|right|A traveler with a Buruli ulcer on the leg.]]
-Mycobacterium ulcerans is a slow-growing mycobacterium that produces a unique toxin, mycolactone, which is responsible for the extensive skin ulcerations and necrosis observed in Buruli ulcer. This toxin has immunosuppressive properties, aiding the bacterium in evading the host's immune response. The bacterium is acid-fast, a characteristic it shares with other mycobacteria, due to the high lipid content in its cell wall.
-==Epidemiology==
+'''Mycobacterium ulcerans''' is a slow-growing [[bacterium]] that is the causative agent of [[Buruli ulcer]], a chronic debilitating skin and soft tissue infection. This organism is part of the [[Mycobacterium]] genus, which also includes the pathogens responsible for [[tuberculosis]] and [[leprosy]].
-The disease caused by ''Mycobacterium ulcerans'', Buruli ulcer, has been reported in over 30 countries, with the highest incidence rates in West Africa, Australia, and Japan. The infection is more common in rural communities located near water bodies. Both children and adults can be affected, but the disease tends to be more prevalent among children aged between 5 and 15 years.
-==Clinical Presentation==
+=== Characteristics ===
-The initial clinical manifestation of infection with ''Mycobacterium ulcerans'' is usually a painless nodule, plaque, or edema. Without treatment, these lesions can progress to massive ulcers, often leading to significant morbidity due to destruction of skin and soft tissue. Secondary bacterial infection of the ulcers can lead to further complications.
-==Diagnosis==
+Mycobacterium ulcerans is an [[acid-fast bacillus]], meaning it retains certain dyes after being washed with acidic solutions. This characteristic is shared with other mycobacteria. The bacterium grows optimally at temperatures between 29°C and 33°C, which is lower than the body temperature of humans, explaining its predilection for cooler areas of the body such as the skin.
-Diagnosis of ''Mycobacterium ulcerans'' infection is based on clinical presentation, epidemiological history, and laboratory confirmation. Laboratory tests include polymerase chain reaction (PCR) for the bacterium's DNA, culture of the organism, and histopathological examination of biopsy samples.
-==Treatment==
+=== Pathogenesis ===
-The World Health Organization (WHO) recommends a combination of antibiotics, usually rifampicin and streptomycin, for eight weeks as the standard treatment for Buruli ulcer. In some cases, surgical intervention may be necessary to remove necrotic tissue or to repair large ulcers. Early diagnosis and treatment are crucial to prevent disability.
-==Prevention==
+The pathogenesis of Mycobacterium ulcerans is primarily due to the production of a toxin called [[mycolactone]]. Mycolactone is a polyketide-derived macrolide that causes tissue necrosis and immunosuppression. The toxin's effects lead to the characteristic ulcers seen in Buruli ulcer disease.
-Preventive measures for Buruli ulcer are challenging due to the incomplete understanding of the transmission routes of ''Mycobacterium ulcerans''. Avoiding contact with potentially contaminated water and soil in endemic areas may reduce the risk of infection. Public health efforts focus on early detection and treatment to minimize morbidity.
-==Research Directions==
+=== Epidemiology ===
-Research on ''Mycobacterium ulcerans'' and Buruli ulcer is focused on understanding the bacterium's ecology, transmission mechanisms, and pathogenesis. Development of a vaccine and more effective treatments with fewer side effects are also areas of ongoing research.
+Buruli ulcer is most commonly found in rural areas of [[West Africa]], but cases have been reported in over 30 countries worldwide, including regions in [[Australia]], [[Southeast Asia]], and [[South America]]. The exact mode of transmission of Mycobacterium ulcerans is not fully understood, but it is believed to be associated with aquatic environments.
+=== Clinical Presentation ===
+The disease typically begins as a painless nodule or papule, which can progress to a large ulcer with undermined edges. The ulceration is often painless, which can delay diagnosis and treatment. If left untreated, Buruli ulcer can lead to significant morbidity, including scarring and contractures.
+=== Diagnosis ===
+Diagnosis of Mycobacterium ulcerans infection is primarily clinical, supported by laboratory tests such as [[polymerase chain reaction]] (PCR) to detect mycobacterial DNA, [[microscopy]] of stained smears, and [[culture]] of the organism from tissue samples.
+=== Treatment ===
+Treatment of Buruli ulcer involves a combination of antibiotics, typically [[rifampicin]] and [[clarithromycin]] or [[streptomycin]], for a period of 8 weeks. Surgical intervention may be necessary for extensive lesions to remove necrotic tissue and promote healing.
+== Related pages ==
+* [[Buruli ulcer]]
+* [[Mycobacterium]]
+* [[Tuberculosis]]
+* [[Leprosy]]
+{{Mycobacterium}}
-[[Category:Bacterial diseases]]
 [[Category:Mycobacterium]]
-[[Category:Tropical diseases]]
+[[Category:Infectious diseases]]
 [[Category:Skin conditions]]
-{{Medicine-stub}}