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Questions and Answers
What characteristic distinguishes Mycobacterium from other bacteria?
At what temperature do Mycobacterium species best grow?
In an acid fast stain, what color do acid fast Mycobacterium appear?
What is the main mode of transmission for leprosy?
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Which organism has been successfully cultured only in the footpad of mice and armadillos?
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Why is leprosy not highly contagious despite direct contact with an infected individual?
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What is a unique challenge in studying Mycobacterium leprae?
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Which regions are reported to have endemic occurrences of leprosy?
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Which feature is typical for all Mycobacterium species?
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What is the consequence of Mycobacterium's preference for cooler body tissues?
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What is the primary reason leprosy has been historically stigmatized?
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What characterizes tuberculoid leprosy as compared to lepromatous leprosy?
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Which of the following is NOT a symptom of tuberculoid leprosy?
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What type of treatment is effective for lepromatous leprosy?
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Which statement is true about the immune response in lepromatous leprosy patients?
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What physical issues might arise from lepromatous leprosy?
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How is the bacterium associated with leprosy commonly referred to in medical documentation?
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Which of the following best describes the progression of tuberculoid leprosy?
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Which of the following can be a consequence of untreated lepromatous leprosy?
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Which factor distinguishes lepromatous leprosy from tuberculoid leprosy?
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Mycobacterium species are classified as strict anaerobes.
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The only laboratory method successfully used to culture Mycobacterium leprae is through the use of armadillos.
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Mycobacterium bacteria grow best at human body temperature, around 37 degrees Celsius.
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The presence of mycolic acids in the cell wall allows Mycobacterium to be classified as non acid fast.
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Leprosy is considered highly contagious and easily spreads from person to person.
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Leprosy primarily affects the cooler body tissues of the skin and nerves.
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Worldwide, rates of leprosy have increased in the last decade.
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Countries such as Brazil and India have reported endemic occurrences of leprosy.
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M. leprae can be easily cultured in standard laboratory media.
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Recent evidence suggests leprosy might have become endemic in Florida.
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Tuberculoid leprosy is more severe and less common compared to lepromatous leprosy.
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Lepromatous leprosy can potentially lead to permanent scarring and disfigurement.
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Tuberculoid leprosy patients have a weak immune response.
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Mycobacterium leprae is the bacterium associated with leprosy infections.
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Lepromatous leprosy is not easily transmitted to others.
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In tuberculoid leprosy, patients can feel small injuries due to the preservation of nerve function.
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The social stigma around leprosy has led to the disease being referred to as Hansen's Disease.
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Both forms of leprosy can be treated successfully with antibiotics if diagnosed in time.
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Lepromatous leprosy patients have a strong immune response, allowing the infection to stay localized.
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Tuberculoid leprosy infections can result in skin discoloration and loss of sensation.
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Study Notes
Mycobacterium Genus
- Mycobacterium are gram-positive, long, irregularly shaped bacilli that tend to clump together in cords.
- They are strict aerobes and grow slowly compared to other bacteria.
- They prefer cooler temperatures than most human pathogens, growing best several degrees below body temperature.
- Mycobacterium have a waxy mycolic acid in their cell wall that stains acid-fast, making them distinct from other bacteria.
- Mycobacterium are identified using an acid-fast stain, where they appear pink while other bacteria appear blue.
- Mycobacterium tuberculosis and Mycobacterium leprae are important examples of this genus.
Mycobacterium Leprae and Leprosy
- Mycobacterium leprae is a strict parasite that is difficult to culture, with the only successful lab culturing occurring in the footpads of mice and armadillos.
- Like other Mycobacterium species, M. leprae grows slowly and prefers cooler temperatures, infecting cooler tissues like nerves and skin, particularly in the extremities.
- Leprosy rates have decreased globally, but remain endemic in several regions, including Brazil, India, Nepal, parts of Africa, and the western Pacific.
- Evidence suggests leprosy may be becoming endemic in Florida, potentially introduced by travelers and possibly spreading through infected armadillos.
- Though leprosy has been documented since ancient times, certain aspects remain unclear, including the exact mechanism of transmission and the degree of contagiousness.
- Leprosy is acquired through direct contact with an infected person, but transmission is not highly contagious, with prolonged exposure often failing to lead to infection.
- Despite the low contagiousness, historical stigma surrounding leprosy led to social isolation of infected individuals.
- Medical professionals often refer to leprosy as "Hansen's Disease" and M. leprae as "Hansen's Bacillus" to minimize stigma.
Tuberculoid Leprosy
- Tuberculoid leprosy is the less severe and more common form of leprosy.
- It is a slowly progressing infection of the skin and local nerves, resulting in patches of skin discoloration and loss of sensation in and around the patches.
- These patches can occur in the nasal or ocular mucosa.
- Nerve damage leads to loss of sensation and pain perception in the affected skin area.
- Patients with tuberculoid leprosy have a strong immune response, limiting the infection's progression and spread to deeper tissues.
- Tuberculoid leprosy is not easily transmitted and can be effectively treated with antibiotics, especially with prompt diagnosis.
Lepromatous Leprosy
- Lepromatous leprosy is a more serious infection characterized by a weaker immune response, allowing infection to spread throughout the skin, nerves, and deeper tissues.
- While aggressive antibiotic therapy can stop the infection, tissue damage is often irreversible, leading to permanent scarring, disfigurement, and potentially blindness.
- The infection causes disfiguring spongy nodules on the face and extremities, potentially leading to tissue loss in areas like fingers, eyebrows, and the nose.
- While this progression is less common, it is more infectious due to the weaker immune response, resulting in a higher concentration of M. leprae in the patient's skin and tissues.
Mycobacterium Genus
- Mycobacterium are Gram-positive, irregularly shaped bacilli that clump together in cords
- Strict aerobes
- Grow slowly compared to other bacteria
- Prefer cooler temperatures than most human pathogens – optimal growth at 34°C
- Distinctive waxy mycolic acids in their cell wall
- Stain "acid fast" (pink) due to mycolic acids
- Other bacteria stain "non acid fast" (blue)
- Classic way to identify Mycobacterium
- Includes Mycobacterium tuberculosis and Mycobacterium leprae
Mycobacterium leprae
- Difficult to culture
- Only successfully grown in the footpads of mice and armadillos
- Slow-growing, preferring cooler temperatures (34°C)
- Infects cooler body tissues, primarily nerves and skin, especially extremities
- Leprosy rates have fallen globally, but remain endemic in regions like Brazil, India, Nepal, parts of Africa, and the western Pacific
- Evidence suggests leprosy may be becoming endemic in Florida, likely introduced by travelers and spreading through infected armadillos
- Acquired through direct contact with an infected person, but not highly contagious
- Leprosy patients have been historically ostracized, despite low risk to others
- Often referred to as "Hansen's Disease" and "Hansen's Bacillus" due to social stigma
Tuberculoid Leprosy
- Less severe and more common form of leprosy
- Slow-progressing infection of the skin and local nerves
- Causes patches of skin discoloration and loss of feeling around the patches
- May affect nasal or ocular mucosa
- Nerve damage leads to loss of sensation and pain perception in affected areas
- Strong immune response present, preventing infection progression and spreading
- Not easily transmitted
- Treatable with antibiotics, especially with prompt diagnosis
Lepromatous Leprosy
- Much more serious infection with weaker immune response
- Spreads through skin, nerves, and deeper tissues
- Can be stopped with aggressive antibiotic therapy, but tissue damage is often irreversible
- Causes disfiguring spongy nodules on the face and extremities, leading to tissue loss (fingers, eyebrows, nose)
- More infectious than tuberculoid leprosy due to abundant Mycobacterium leprae in infected tissues
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Description
This quiz provides an overview of the Mycobacterium genus, focusing on their characteristics, growth patterns, and significance, particularly Mycobacterium tuberculosis and Mycobacterium leprae. Test your knowledge on acid-fast staining and the unique features that distinguish these bacteria from others.
