Q:
What are the 2 'classical' pathogens to cause tuberculosis?

A:
* Mycobacterium tuberculosis
* Mycobacterium bovis

Q:
What opportunistic pathogenic Mycobacterium species cause atypical mycobacterial infections?

A:
* Mycobacterium kansasii
* MAIS Complex (M. Avium, M. intercellulare, M. scrofulacium)

Q:
True or false? Mycobacterium tuberculosis is a Gram positive coccus.

A:
False. Mycobacterium tuberculosis is an acid fast rod (3 by 0.3 micrometres).

Q:
True or false? Mycobacterium tuberculosis is a facultative anaerobe.

A:
False. Mycobacterium tuberculosis is a strict aerobe.

Q:
True or false? Mycobacterium tuberculosis lasts so long in the immune system because its cell wall is not well detected by the immune system.

A:
False. Mycobacterium tuberculosis' cell wall constituents are powerful stimulators of the immune system.

Q:
True or false? Mycobacterium tuberculosis contains a waxy substance known as myopyloenic acid in its cell wall.

A:
False. Mycobacterium tuberculosis contains a waxy substance known as *mycolic* acid in its cell wall.

Q:
True or false? The mycolic acid present in the cell wall of Mycobacterium tuberculosis makes it resistant to chemical and physical agents such as antibiotics, disinfectants and drying.

A:
True.

Q:
What are the symptoms of tuberculosis?

A:
* Chronic cough or haemoptysis
* Malaise
* Weight loss
* Pyrexia (and sometimes night sweats)

Q:
What are some of the features of the transmission of tuberculosis?

A:
* Humans are the main reservoir
* It is spread by droplet nuclei
* It can be spread by fomites (inanimate objects or substances capable of transmitting infectious organisms from one individual to another)
* Can be spread by toilet flush aerosal from individuals with renal TB (not a common route)
* M. bovis can be spread via milk consumption (there are TB eradication programs present in the dairy industry)
* Possible spread from opportunistic species present in the environment

Q:
What are 'saprophytes'?

A:
Organisms which take up non-living nutrients in disolved form, usually growing on decomposing organic matter.

Q:
What percentage of TB organisms survive after being aerosolised for 3 hours at room temperature?

A:
>60%.

Q:
What percentage of TB organisms survive after being aerosolised for 9 hours at room temperature?

A:
>30%.

Q:
What are the features of Ziehl Neelsen Staining?

A:
* Basic fuchsin/phenol + heat (melts waxy coat)
* Acid - alcohol wash
* Methylene blue counterstain
* Acid fast organisms stain pink

Q:
True or false? Microbiologists may spend up to 15-20 minutes searching a suspected tuberculosis patient slide because a single acid fast bacillus (AFB) is diagnostic.

A:
True.