Flashcards in Overview of mycobacteria Deck (48)
How are mycobacterium classified?
into slow growing vs rapid growing
Where are rapidly growing mycobacteria mainly found?
in the soil
What type of bacteria are mycobacteria?
aerobic non-motile weakly gram positive bacilli
What medium is generally used for culturing of mycobacteria?
What stain is used to identify mycobacteria?
What does acid-fast mean?
able to resist decolourisation with acidified alcohol when stained with an arylmethane stain
What other genus of bacteria are acid fast?
What does acid-fastness depend on?
the integrity of the waxy envelope
What is found on the outside of mycobacetria cell walls?
high lipi content- lots of mycolic acids
What does the mycobacterial cell wall allow them to do?
resist intracellular phagocytosis; complement lysis and is impermable to lots of abx
What are the 3 types of obligate human pathogens of the mycobacteria tuberculosis complex ?
M-tuberculosis; M. africanum and M.canneti
Where are M.africanum and M.canneti foudn?
M.africanum- west africa; M. canneti- east africa
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
What is DOTS?
directly observed therapy short course
What is the general transformation of latent TB to active TB per year?
Why is monotherapy in treating TB not used?
always leads to drug resistance
What is the treatment for latent TB?
9 months of isoniazid
What causes the lung disease in TB?
immune response to the infection
What is the oldest known human specific infection?
Leprosy- Hansen's disease
What is the big problem with mycobacterium leprae?
cannot be cultured in labs- has to be in vivo
How is mycobacterium leprosae diagnosed?
demonstrating acid-fast bacilli in skin biopsies
What organisms does mycobacterium leprae grow in?
9 banded armadillo or the mouse footpad
What is leprosy?
a chronic infection of the skin and nerves
What are the 2 types of leprosy?
paucibacillary leprosy and multibacillary leprosy
What is the differnece between PB and MB?
PB- negative smears at all sites; MB- positive smear at any site
How is leprosy transmitted?
Waht is the treatment for multibacillary leprosy?
rifampicin, clofazimine and dapsone for 6-12 months
what is hte treatment for paucibacillary leprosy?
rifampicin and dapsone for 6-12 months
Who does M.ulcerans affect?
school age children