Diphtheria is caused by the bacterium Corynebacterium diphtheriae, primarily transmitted through human carriers and characterized by respiratory or skin-related symptoms. Diagnosis involves culture and specific staining techniques, with treatment typically requiring penicillin or erythromycin. Vaccination with diphtheria toxoid is crucial for prevention, given to children at specified intervals, with subsequent boosters into adolescence.

1. Diphtheria
Dr. Rachana Choudhary
Department of Microbiology
Shri Shankaracharya Mahavidyalaya Junwani
Bhilai

2. Introduction
 It is Caused by Aerobic Gram +ve rods
Cornybacterium diphtheria.
 Exotoxin production only if infected by virus
phage infected carrying toxin gene.

3. Gram +ve Bacilli and Colonies

4. Epidemiology
 Reservoir Human carriers
Usually asymptomatic
 Transmission Respiratory
Skin and fomites rarely
 Temporal pattern Winter and spring
 Communicability Up to several weeks
without antibiotics

5. Clinical Features
 Incubation period 2-5 days
(range, 1-10 days)
 May involve any mucous membrane
 Classified based on site of infection
Anterior nasal
Pharyngeal
Tonsillar
Laryngeal

6. Anterior Nasal

7. Thick Membrane

8. Pseudo membrane

9. ‘Bull Neck’

10. Skin Lesions

11. Symptoms

12. Diagnosis
 Culture
 Fluorescent antibody technique
 Albert`s staining

13. Culture

14. Fluorescent Antibody Techniques
Figure 18.10a

15. Albert staining

16. Treatment
Penicillin :
 Procaine penicillin ( 3 – 6 units IM at 12 hourly)
 Oral penicillin ( 125 – 250 mg units)
 Erythromycin ( 25 – 30 mg / kg / day ) for 14 days
 Three negative cultures at 24 hours
intervals should be obtained before the
patient is declared free of the organism

17. Retention of Penicillin G
Figure 20.7

18. Prevention
Vaccination: Immunisation with diphtheria
toxoid, combined with tetanus and pertussis
toxoid (DTP vaccine), should be given to all
children at two, three and four months of age.
The child is given a further booster vaccine before
leaving school and is then considered to be
protected for a further 10 years (16 – 18 years).

19. Reference
Book Writer
 Medical Microbiology P. Chakraverti
 Microbiology Dubey and Maheshwari
 Immunology Kubey