Cornybacterium Diphtheriae Flashcards
What shape is C.diphteriae?
CLUB SHAPED ROD
Is C.diphtheriae gram positive or gram negative?
Gram positive - thick peptidoglycan
-takes purple stain
Outline the 3 main morphology of C.diphtheriae?
Non sporing
Non motile
Non capsulated
What special feature is found at the poles of C.diphtheriae and what dye is used to visualise them?
Metachromatic granules
> “babe ernst granules”
> methylene blue dye is used to visualise metachromatic granules
What kind of arrangement does C.diphtheriae form?
Cuniform arrangement
“chinese letters”
How is C.diphtheriae transmitted?
> through air droplets
> hand contact
Who is most at risk of C.diphtheriae?
Childrens 1-5years
newborns are protected by maternal antibody
Where does C.diphtheriae colonise in human body?
PHARYNX
Does C.diphtheriae cause TOXEMIA OR BACTERIMEA? explain why?
causes TOXIEMIA as it is non-motile and colonises in the pharynx
> produces toxins which are released into the bloodstream = TOXIEMIA
What medium is used to select for Cornybacterium and other gram positive bacterium and eliminates G negatives?
MEDIUM WITH TELLURITE - used to select Cornybac. + other gram +
2 kinds of TELLURITE:
> CYSTINE TELLURITE
> TINSDALE - helps to differentiate amongst different CORNYBACTERIUMS
What medium is used to differentiate between cornybacteriums?
TINSDALE MEDIUM
How many different types of Cornybacterium diphtheriae are found on tellurite medium? name each of them
3 morphological types of C. diphtheria found on tellurite medium
> MITIS
GRAVIS
INTERMEDIUS
What is common in all 3 morphological types of C.diphtheriae?
all produce same type of EXOTOXINS
What is the main virulence factor of C.diphtheria?
EXOTOXIN which causes diphtheria
FRAGMENT A: toxic activity
FRAGMENT B: binding the toxin to cells
What is the function of the toxins produced by C. diphtheriae?
the toxin inhibits protein synthesis by ADP ribosylating elongation factor 2
