1. Corynebacteria
Filename: Coryne.ppt

2. Outline Microbes Diseases Corynebacterium,Listeria, Erysipelothrix
Diphtheria,Listeriosis, Erysipeloid

3. Corynebacterium: Habitat
Skin
upper respiratory tract
GI tract
Urogenital tract of humans

4. Cornyebacterium: Pathogens
C. diphtheriae Diphtheria
C.pseudotuberculosis humans sheep, cattle, suppurative lymphadenitis
C. ulcerans humans pharyngitis
cattle -mastitis
C. haemolyticum pharyngitis cutaneous infection
C. pyogenes cattle, sheep, swine suppurative infection
C.pseudodiphtheriticum endocarditis

5. C. xerosis
opportunistic infections
Group J K immunocompromised host

6. Related Organisms Listeria monocytogenes Erysipelothrix rhusiopathiae
Listeriosis
Erysipelothrix rhusiopathiae
Erysipeloid

7. Diphtheria

8. Diphtheria Laboratory diagnosis
Speedy diagnosis
Differentiate from commensals
“diphteroids”
nose & throat
C. xerosis C. hofmanni
Throat swabs (confirmatory)
Blood Tellurite
Virulence test

9. Corynebacterium Aerobic gram + rods -pleomorphic: club-shaped
-pallisades
-snapping cell division
-metachromatic granules
methylene blue stain
volutin: polyphosphate

10. Cellular Morphology Gram positive rods “Snapping division”
Palisade cells
“Chinese letters”
Erysipelothrix

11. Specialized media Tellurite: black colonies
Not diagnosticallly significant
tellurite inhibits many organisms but not C. diphtheriae
Loeffler
best colonial morphology
Dextrose horse serum (1887)
now Dextrose beef serum

12. Blood tellurite Selective & differential medium
Corynebacteria are resistant to tellurite
Reduced to tellurium
Forms deposit in colonies
Colonies appear dark
Biotypes
gravis, intermedius, mitis

13. Corynebacterium Biotypes
C diphtheriae gravis
C diphtheriae intermedius
C diphtheriae mitis
Helpful for epidemiological tracing
Culture identified by biochemical tests.

14. DIAGNOSIS MUST BE CLINICAL!!!!
Diphtheria
Nasopharyngeal diphtheria
Pharyngeal
Larygngeal
Cutaneous diphtheria
Systemic complications
DIAGNOSIS MUST BE CLINICAL!!!!

15. Pharyngeal diptheria Inflammation Leucocytes TOXIN !!
similar to strept throat
Leucocytes
infiltrated
killed
embedded in fibrin clot
TOXIN !!

16. All SIGNS & SYMPTOMS CAUSED BY TOXIN
Diphtheria Symptoms
Pharyngitis
Hypoxia
Choking
“Garitillo”
Fever (103 F)
Lymphadenitis
All SIGNS & SYMPTOMS CAUSED BY TOXIN

17. Diphtheria Pseudomembrane
No True membrane
Very few live cells
Deposit of dead cells and protein

18. Pseudomembrane CONTAINS COVERS tonsils, bacteria uvula, lymphocytes
plasma cells
fibrin
dead cells
COVERS
tonsils,
uvula,
palate
nasopharynx
larynx.

19. Diphtheria Systemic complications
Nerves
toxic peripheral neuropathy
paralysis of short nerves
mouth, eye, facial extremities
Cardiac
Congestive heart failure
high amount of toxin hours
Low amount of toxin 2-6 weeks

20. Virulence Factors Diphtheria toxin !!! Dermonecrotic toxin Hemolysin
blocks protein synthesis
Dermonecrotic toxin
sphingomyelinase
increases vascular permeability
Hemolysin
Cord factor -Toxic trehalose
corynemycolic acid, corynemyolenic acid
6,6’-di-O-mycoloyl- a,a’-D-trehalose

21. DiphtheriaToxin Blocks protein synthesis Protein 63Kd
controlled by Tox gene
lysogenic phage Beta-corynephage
expressed if [iron] low
2 components A-B

22. Regulation of Diphtheria Toxin High [Fe 2+]
NO Toxin Produced P o
tox
Corynebacteriophage beta
Fe 2+ + apo DtxR
[Fe 2+ *DtxR] p
dtxR
C diphtheriae
dtxR= repressor protein

23. Regulation of Diphtheria Toxin Low [Fe 2+]
Toxin Produced!!!
tox
Corynebacteriophage beta o P
Fe 2+ + apo DtxR
[Fe 2+ *DtxR]

24. Toxin Part A Part B Active site N terminal Enzyme Binding site
Binds to membrane receptor
Transmembrane

25. Diphtheria toxin: Part A
Active site
Enzyme
Blocks protein synthesis
ADP-ribosyl transferase
elongation factor 2 (EF2)
Specific for mammalian cells
Prokaryotes have different EF2

26. Diphtheria Toxin: Part B
Binding Site
Binds to cell receptor
Bound receptor internalized
Endosome
Hydrolysed by protease
Disulfide broken
Part A released

27. Activation of Diphtheria ToxinB A B A B A B

29. Toxingenicity Tests In Vitro Elek test In Vivo Animal inoculation
rabbit skin test-necrosis
guinea pig challenge test- lethal
low [Fe 2+] induces toxin

30. Elek test

31. Animal inoculation Inject 2 mice with 5ml C.diphtheria cells
one mouse protected with 1000 units C.diphtheriae antitoxin
Autopsy - adrenals hemorrhagic

32. Control Immunization diphtheria toxoid Schick test Passive immunity
check for antibodies
Passive immunity
Antibodies
Antibiotics
Penicillin & erythromcyin

33. Schick Test for Diptheria

34. Epidemics Immune individuals Non immune individuals may be carriers
antibiotics
Non immune individuals
Exposed
passive immunity antibodies
Not exposed
immunize with toxoid

35. Diphtheria: Russian Federation

36. Diphtheria in the Soviet Union and NIS
Emerging infectious diseases: 4(4) 1998 Vitek & Wharton

37. Diphtheria Incidence

38. Diphtheria in the Russian Federation

39. The End

40. Performance Objectives
Key terms, concepts
short answers

41. Key Terms
pseudomembrane

42. Key Terms Schick test Elek Test Diphtheria toxin larnygeal diphtheria
pharyneal diphtheria

43. Key Organisms
Corynebacterium
Listeria
Erysipelothrix

44. Key Concepts

45. Epidemiology of Diphtheria
Disease/bacterial factors
Transmission
Who is at risk
Geography/ season
Incidence
Modes of control

46. Short Answers
Construct a table of the virulence factors associated with diphtheria and the biological activity of each
Use a series of no more than four diagrams to describe the mechanism of action of diphtheria toxin
Describe the clinical manifestations of diphtheria
Construct a table listing the common Corynebacteria and the associated diseases.