Mycobacterium, the Acid Fast Genus
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Questions and Answers

What characteristic distinguishes Mycobacterium from other bacteria?

  • They have a spherical shape.
  • They are strict anaerobes.
  • They contain mycolic acids in their cell wall. (correct)
  • They reproduce by binary fission.
  • At what temperature do Mycobacterium species best grow?

  • 24 degrees Celsius
  • 37 degrees Celsius
  • 34 degrees Celsius (correct)
  • 30 degrees Celsius
  • In an acid fast stain, what color do acid fast Mycobacterium appear?

  • Yellow
  • Green
  • Pink (correct)
  • Blue
  • What is the main mode of transmission for leprosy?

    <p>Direct contact with an infected person</p> Signup and view all the answers

    Which organism has been successfully cultured only in the footpad of mice and armadillos?

    <p>Mycobacterium leprae</p> Signup and view all the answers

    Why is leprosy not highly contagious despite direct contact with an infected individual?

    <p>Prolonged contact is needed for transmission.</p> Signup and view all the answers

    What is a unique challenge in studying Mycobacterium leprae?

    <p>It cannot be cultured using standard techniques.</p> Signup and view all the answers

    Which regions are reported to have endemic occurrences of leprosy?

    <p>Brazil, India, and parts of Africa</p> Signup and view all the answers

    Which feature is typical for all Mycobacterium species?

    <p>They are strict aerobes.</p> Signup and view all the answers

    What is the consequence of Mycobacterium's preference for cooler body tissues?

    <p>They primarily infect nerve and skin tissues of extremities.</p> Signup and view all the answers

    What is the primary reason leprosy has been historically stigmatized?

    <p>People lack knowledge about the disease and its transmission.</p> Signup and view all the answers

    What characterizes tuberculoid leprosy as compared to lepromatous leprosy?

    <p>It has a strong immune response preventing further diseases.</p> Signup and view all the answers

    Which of the following is NOT a symptom of tuberculoid leprosy?

    <p>Formation of spongy nodules.</p> Signup and view all the answers

    What type of treatment is effective for lepromatous leprosy?

    <p>Aggressive antibiotic therapy.</p> Signup and view all the answers

    Which statement is true about the immune response in lepromatous leprosy patients?

    <p>It is weak, leading to further infection spread.</p> Signup and view all the answers

    What physical issues might arise from lepromatous leprosy?

    <p>Permanent scarring and disfigurement.</p> Signup and view all the answers

    How is the bacterium associated with leprosy commonly referred to in medical documentation?

    <p>Hansen's Bacillus.</p> Signup and view all the answers

    Which of the following best describes the progression of tuberculoid leprosy?

    <p>It remains localized and progresses slowly.</p> Signup and view all the answers

    Which of the following can be a consequence of untreated lepromatous leprosy?

    <p>Formation of facial deformations.</p> Signup and view all the answers

    Which factor distinguishes lepromatous leprosy from tuberculoid leprosy?

    <p>Severity of tissue damage.</p> Signup and view all the answers

    Mycobacterium species are classified as strict anaerobes.

    <p>False</p> Signup and view all the answers

    The only laboratory method successfully used to culture Mycobacterium leprae is through the use of armadillos.

    <p>True</p> Signup and view all the answers

    Mycobacterium bacteria grow best at human body temperature, around 37 degrees Celsius.

    <p>False</p> Signup and view all the answers

    The presence of mycolic acids in the cell wall allows Mycobacterium to be classified as non acid fast.

    <p>False</p> Signup and view all the answers

    Leprosy is considered highly contagious and easily spreads from person to person.

    <p>False</p> Signup and view all the answers

    Leprosy primarily affects the cooler body tissues of the skin and nerves.

    <p>True</p> Signup and view all the answers

    Worldwide, rates of leprosy have increased in the last decade.

    <p>False</p> Signup and view all the answers

    Countries such as Brazil and India have reported endemic occurrences of leprosy.

    <p>True</p> Signup and view all the answers

    M. leprae can be easily cultured in standard laboratory media.

    <p>False</p> Signup and view all the answers

    Recent evidence suggests leprosy might have become endemic in Florida.

    <p>True</p> Signup and view all the answers

    Tuberculoid leprosy is more severe and less common compared to lepromatous leprosy.

    <p>False</p> Signup and view all the answers

    Lepromatous leprosy can potentially lead to permanent scarring and disfigurement.

    <p>True</p> Signup and view all the answers

    Tuberculoid leprosy patients have a weak immune response.

    <p>False</p> Signup and view all the answers

    Mycobacterium leprae is the bacterium associated with leprosy infections.

    <p>True</p> Signup and view all the answers

    Lepromatous leprosy is not easily transmitted to others.

    <p>False</p> Signup and view all the answers

    In tuberculoid leprosy, patients can feel small injuries due to the preservation of nerve function.

    <p>False</p> Signup and view all the answers

    The social stigma around leprosy has led to the disease being referred to as Hansen's Disease.

    <p>True</p> Signup and view all the answers

    Both forms of leprosy can be treated successfully with antibiotics if diagnosed in time.

    <p>True</p> Signup and view all the answers

    Lepromatous leprosy patients have a strong immune response, allowing the infection to stay localized.

    <p>False</p> Signup and view all the answers

    Tuberculoid leprosy infections can result in skin discoloration and loss of sensation.

    <p>True</p> Signup and view all the answers

    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.

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