Mycobacteria Flashcards
What are the unique characteristics of Mycobacterial cell walls?
Acid fast bacteria with a layer of peptidoglycan surrounded by layer of arabinogalactan surrounded by outermost layer of mycolic acid. Gives cell waxy texture that makes it resistant to drying out and antimicrobial agents.
What does Mycobacterium tuberculosis cause?
Causes TB, a respiratory disease characterized by nodules in the lung
What is Arabinogalactan made of?
D-arabinose and D-galactose.
What is the virulence factor of M. tuberculosis?
Cell walls contain cord factor, which enhances its survival in host by preventing phagosome-lysosome fusion.
What is the treatment for tuberculosis?
Combination antibiotics for a number of months. If drug resistant, must be treated with expensive drugs up to 2 years.
What are the 3 types of tuberculosis?
Primary=initial infection
Secondary= reestablishment of dormant infection
Disseminated= Systemic infeciton
What does the tuberculoid Mycobacterium leprae cause?
Cell mediated, non progressive disease that is characterized by loss of sensation in regions of the skin.
What does the Lepromatous Mycobacterium leprae cause?
Anti-body mediated, gradual tissue destruction that results in loss of facial features, digits, and other structures.
How can M Leprae be cultivated?
Can’t be cultivated in vitro, only the the footpads of mice and bellies of 9-banded armadillos.
What is the virulence factor of M. leprae?
Virulent due to structure of mycobacterium cell wall.
WHat is the treatement for tuberculoid leprosy? Lepromatous form?
Tuber=dapsone and rifampin 6 mo
Lep= Dapsone, rifampin, clofazamine 2 years, dapsone 10 more years.
What is Mycobacterium ulcerans cause? How?
Causes buruli ulcer. Associated with slow moving bodies of water, enters through skin abrasions and grows extracellularly. Skin is destroyed and sloughed off revealing large ulcer underneath.
What is the virulence factor of M ulcerans?
produces polyketide toxin Mycolactone, which destroys skin tissue and acts as immunosuppressant.
How is M. ulcerans treated?
No reliable drug therapy, treated with skin grafts.
