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Flashcards in Overview of mycobacteria Deck (48)
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1

How are mycobacterium classified?

into slow growing vs rapid growing

2

Where are rapidly growing mycobacteria mainly found?

in the soil

3

What type of bacteria are mycobacteria?

aerobic non-motile weakly gram positive bacilli

4

What medium is generally used for culturing of mycobacteria?

Lowenstein-Jensen

5

What stain is used to identify mycobacteria?

acid-fast stain

6

What does acid-fast mean?

able to resist decolourisation with acidified alcohol when stained with an arylmethane stain

7

What other genus of bacteria are acid fast?

Nocardia

8

What does acid-fastness depend on?

the integrity of the waxy envelope

9

What is found on the outside of mycobacetria cell walls?

high lipi content- lots of mycolic acids

10

What does the mycobacterial cell wall allow them to do?

resist intracellular phagocytosis; complement lysis and is impermable to lots of abx

11

What are the 3 types of obligate human pathogens of the mycobacteria tuberculosis complex ?

M-tuberculosis; M. africanum and M.canneti

12

Where are M.africanum and M.canneti foudn?

M.africanum- west africa; M. canneti- east africa

13

What are the main reasons for the decline in TB in the 19th and 20th centures in britain?

transmission decreased and improved nutrition; genetics- selective pressures leading to more people being resistant; M.tuberculosis has become less pathogenic

14

What is DOTS?

directly observed therapy short course

15

What is the general transformation of latent TB to active TB per year?

5-10%

16

Why is monotherapy in treating TB not used?

always leads to drug resistance

17

What is the treatment for latent TB?

9 months of isoniazid

18

What causes the lung disease in TB?

immune response to the infection

19

What is the oldest known human specific infection?

Leprosy- Hansen's disease

20

What is the big problem with mycobacterium leprae?

cannot be cultured in labs- has to be in vivo

21

How is mycobacterium leprosae diagnosed?

demonstrating acid-fast bacilli in skin biopsies

22

What organisms does mycobacterium leprae grow in?

9 banded armadillo or the mouse footpad

23

What is leprosy?

a chronic infection of the skin and nerves

24

What are the 2 types of leprosy?

paucibacillary leprosy and multibacillary leprosy

25

What is the differnece between PB and MB?

PB- negative smears at all sites; MB- positive smear at any site

26

How is leprosy transmitted?

nasal discharges

27

Waht is the treatment for multibacillary leprosy?

rifampicin, clofazimine and dapsone for 6-12 months

28

what is hte treatment for paucibacillary leprosy?

rifampicin and dapsone for 6-12 months

29

Who does M.ulcerans affect?

school age children

30

What is the symptom of M.ulcernas?

large painless ulcer