Mycobacterium

Question 1

Explain the epidemiology and etiology of Mycobacterium:

1. Who first described tubercle bacillus?
2. What was used for the study of the chain of infection and Postulates/Germ theory?

Answer 1

1. was first described by Robert Koch, German Bacteriologist, in 1882, “The Etiology of tuberculosis”, was the first to characterize/scientifically described Mycobacterium as a disease
2. used M.tuberculosis w/bacillus anthracis for the chain of infection and germ theory, used it to determine germ theory/Koch’s postulates/chain of infection, used

Question 2

Describe the taxonomy of Mycobacterium:

1. How many species are there predicted to be?
2. What phylum do they belong to?
3. Which ones are opportunistic and obligate?
4. What are granulomas and what is a gramulomatis disease?
5. What does MOTT mean? NTM?

Answer 2

1. over 150 species of Mycobacterium
2. belong to the phylum, Actinobacteriacae
3. (1) M.tuberculosis, (2) M. bovis (3) M. leprae (4) M. Ulcerans (5) Mott (AKA, NTM), most of the species do not cause human disease
4. Granulomas are immune tissue that are formed as response to antigens , attempt of the immune system to wall off at the site of infection to what is causing that infection, present in the dermis are are disfiguring
5. MOTT- Mycobacterium Other Than Tuberculosis, NTM- Non-tuberculosis Mycobacterium

Question 3

Describe the Morphology of Mycobacterium

Answer 3

• Slender
• Curved
• Non-motile bacilli
• Non-spore forming
• do not mistake from vibrio

Question 4

Answer this question about Mycobacterium:

1. While gram positive, Mycobacterium species are non-reactive by the gram-stain. Why does this happen?
2. Explain the role mycolic acid has in the cell wall.
3. What is a mycomembrane and what is its function?

Answer 4

1. This is due to the unique cellular envelope structure, it contains novel membrane liquid and protein chemistries, mycolic acid
2. it is covalently linked to the cell wall, forming the mycomembrane (layer of fat), not a typical lipid bi-layer, fat composed of mycolic acids, interjected with free lipids, of which are heavily glycosylated, form a capsule, mycomembrane is chemically attached to cell wall (pepi)
3. it is a capsule, it may promote macrophage phagocytosis by immune cells

Question 5

Answer these questions about Mycobacterium, Mycolic Acid:

1. Why type of dyes does mycolic acid retain and what can it be used for?
2. What does the mycomembrane protect the mycobacterium from and what does it contribute to?

Answer 5

1. it retains carbofuchsin dyes, acid-fast dyes, it can be used as a rapid diagnostic tool in sample smears, mycolic acid fat
2. it protects the mycobacterium from various stressors (ex.dissication), antimicrobial (disinfectants and antibiotics), may contribute to immune evasion, this is due to its low permeability

Question 6

Answer these questions about the Epidemiology of Mycobacterium:

1. How much of the worlds population has T.B.?
2. How many estimated infections/deaths are there a year?
3. Does T.B. have drug resistance?
4. How does T.B. enter the lungs?
5. How many T.B. infections are asymptomatic?

Answer 6

1. 1/3 of the worlds population infected with TB, in the last century it has killed >100 million people
2. enormous global disease burden, there are an estimated 10 million infections per year and over 1.8 million deaths per year, top 10 causes of death globally
3. TB has multi-drug resistance, and has been increasing over the decades
4. it enters the lung alveoli by airborne transmission during active pulmonary disease, aka- pulmonary TB, aresolized- direct transmission, highly contagious
5. over 90% of infections are asymptomatic, aka- Latent TB(LTBI) , progression to active TB is attributed with compromised immunity (HIV infection), can exist in a carrier state, pulmonary is one form of Active TB
   
   • the most impactful infection to date

Question 7

Answer these questions regarding M.bovis:

1. What type of disease it it similar to?
2. How can it be transmitted?
3. Can it be transmitted to humans?

Answer 7

1. similar to tuberculosis, causes a tuberculosis-like disease, bovine TB, in non-human animals, [cattle, deer, elk-ungulates], tubercles in the lungs
2. can be transmitted by aerosol/ contaminated foods [dairy] to humans
3. yes it can be transmitted to humans via food contamination