1. ‫بسم ا الرحمن الرحيم‬
GENUS:
CORYNEBACTERIUM
Prof. Khalifa Sifaw Ghenghesh

2. •
•
•
•
•
Diptheroides = Coryneforms
Gram +ve,
Nonmotile Rods.
Arranged in V forms or Palisades
Catalase +ve

3. 1. Corynebacterium diphtheriae
• Diphtheria.
Morphology
• Pleomorphic Bacilli
• Cells Contain Metachromatic Granules.

4. Corynebacterium diphtheriae
Club-shaped, Gram-positive rods

5. Cultural Characteristics
• i. Loeffler's Serum Slope.
• ii. Tellurite BA.
- Temp. 37oC,
- Aerobic and Facultative AnO2.

6. Corynebacterium diphtheriae forms black
colonies on tellurit agar (left), on blood agar
colonies appear white (right)

7. PATHOGENICITY
• Diphtheria is a Toxaemia.
– Exotoxin: M. wt 62000
– 2 Fragaments >> A & B
– Inhibits Protein Synthesis.
– Has Special Affinity for Certain Tissues
"Mycocardium, Adrenals, Nerve Endings".
• Toxin >> Toxoid.
• Site of Infection >> Faucial.
– Toxin >> Pseudomemebrane.

8. LABORATORY DIAGNOSIS
• Important >> Specific Treatment Should Be
Started
Immediately on Suspicion of Diphtheria.
• Specimen: Two Swabs from the Lesion.
• Culture:
i. Loeffler's Serum Slope >> Albert Stain.
ii. Tellurite BA.
iii. BA >> Streptococcal or Staphylococcal
Pharyngitis.

9. PATHOGENICITY TESTS
• In-vivo Tests:
i. Subcutaneous Test:
ii. Intracutaneuos Test:
• In-vitro Test:
– Elek Test ( Gel Precipitaion Test).
• Tissue Culture:

10. TREATMENT
• i. Antitoxin: > Moderate Cases:
> Severe Cases:
• ii. Antibiotic:
PREVENTION
• i. Active Immunization >> PDT.
• ii. Passive Immunization:
• iii. Combined:

11. SCHICK TEST
• > Injection of 0.2 ml of Diphtheria Toxin
Intradermally.
• > Positive Reaction >>
Erythema +
Swelling

12. SCHICK TEST
______________________________________________________________________
Result
Test Arm
Control Arm
Interpretation
Diphthri
(Toxin)
Inactivated Toxin
Immunization
36h 120h
36h 120h
______________________________________________________________________
Negative
----Immune,
Not
Not Hypersensitive Required
--------------------------------------------------------------------------------------Positive
+
+
--
--
Not Immune, Not Required
Hypersensitive
--------------------------------------------------------------------------------------------------------------------Negative
+
-+
-Immune
Not
Hypersensitive
Required
--------------------------------------------------------------------------------------------------------------------Positive &
+
+
+
-Not Immune
ContraPseudo
Hypersensitive
indicated
______________________________________________________________________

13. ‫بسم ا الرحمن الرحيم‬
Listeria monocytogenes

14. • Listerosis.
•
•
•
•
•
G+ve Coccobacilli > in Short Chains.
Motile at 25oC But Not at 37oC.
Aerobic to Microaerophilic.
On BA > Narrow Zone of β-Haemolysis.
Listerolysin O >

15. • Incidence and Transmission >
DISEASE
• i. In Adults:
• ii. Neonatal Infections:
a. Early Type:
b. Late Type:

16. LABORATORY DIAGNOSIS
• i. Specimen: Depend on Syndrome: Blood,
CSF, Genital Tract Secretions.
• ii. Media: Selective Media.
TREATMENT
• Penicillin, Ampicillin.