Bacteriology (Gram Positive Bacilli)

Corynebacterium diphtheriae
Listeria monocytogenes

Gram (+) Bacilli
Non-spore forming
Catalase (+)
Non-branching

Corynebacterium diphtheriae

Gram (+) Bacilli that is isolated from human nasopharynx and not a normal flora

Brainpower

Read More

Kleb Loeffler's Bacillus

Corynebacterium diphtheriae

Common name

Club-shaped
Chinese character
Picket-fence
X and Y arrangement

Corynebacterium diphtheriae

C. diphtheriae is a pleomorphic bacilli that may appear as:

a. Lipophilic

b. Catalase, Oxidase, Nitrate (-) → Catalase, Oxidase, Nitrate (+)

c. Urease (+) → Urease (-)

d. Non-aerobic and motile → Aerobic and Nonmotile

Corynebacterium diphtheriae

Which is true?

a. Lipophilic

b. Catalase, Oxidase, Nitrate (-)

c. Urease (+)

d. Non-aerobic and motile

Urease (-)

C. diphtheriae - Urease (-)
C. ulcerans, C. pseudotuberculosis - Urease (+)

Corynebacterium diphtheriae

Used to distinguish C. diphtheriae from C. ulcerans and C. pseudotuberculosis

Metachromatic granules

Corynebacterium diphtheriae

Inclusion bodies

Respiratory form

Corynebacterium diphtheriae

Most common form of disease that promotes necrosis

Bull's neck

Corynebacterium diphtheriae

Appearance of Respiratory Form of disease

Cutaneous form

Corynebacterium diphtheriae

Diphtheriae common in the tropics

Ecthyma dihptheriticum

Corynebacterium diphtheriae

Initial ulcerative lesion manifested as nonhealing ulcers with a dirty gray membrane

BAP
CAP
CTBA
Tinsdale Agar

Corynebacterium diphtheriae

Culture Media

Loeffler's Serum Agar / Pai's Slant

Corynebacterium diphtheriae

Media useful for morphology and demonstration of metachromatic granules

CTB Agar

Corynebacterium diphtheriae

Preferred medium and modification of Tinsdale medium

Black, Gunmetal colonies

Corynebacterium diphtheriae

Colony morphology on CTBA

Narrow zone of B-hemolysis

Corynebacterium diphtheriae

Colony morphology on BAP

Black colonies with brown halo

Corynebacterium diphtheriae

Colony morphology on Tinsdale Medium

Gray Black colonies

Corynebacterium diphtheriae

Colony on Potassium Tellurite

Gravis
Mitis
Intermedius

Corynebacterium diphtheriae

Biotypes:

Gravis

Corynebacterium diphtheriae

Biotype with largest colony type

Mitis

Corynebacterium diphtheriae

Biotype with fried egg colony on BAP

Intermedius

Corynebacterium diphtheriae

Biotype with small, gray, translucent colonies

(+)

Corynebacterium diphtheriae

All biotypes are NO3 (+, -)

Gravis

Corynebacterium diphtheriae

All biotypes are starch (-) except:

Animal inoculation using guinea pigs

Corynebacterium diphtheriae

In vivo test for Dihptheria toxin

Modified Elek Test

Corynebacterium diphtheriae

In vitro test for Dihptheria toxin

Fine precipitin lines at 45 deg angle

Corynebacterium diphtheriae

(+) result for Modified Elek Test

Vero Cell Cytotoxicity Assay

Corynebacterium diphtheriae

Gold standard for Diphtheria Toxin Production

PCR
Schick's Test

Corynebacterium diphtheriae

Molecular methods

PCR

Corynebacterium diphtheriae

Molecular method used for the

Schick's Test

Corynebacterium diphtheriae

Skin test for susceptibility to diphtheriae

C. jeikeium

Corynebacterium

Causes prosthetic device infection and immunocompromised infections

JK Bacteria

Corynebacterium diphtheriae

C. jeikeium is also known as:

Metallic sheen

Corynebacterium diphtheriae

C. jeikeium on BAP