1. ‫مممممم‬ ‫مممممم‬ ‫مممم‬ ‫ممم‬‫مممممم‬ ‫مممممم‬ ‫مممم‬ ‫ممم‬
FAMILY: BACILLACEAEFAMILY: BACILLACEAE
Prof. Khalifa Sifaw GhengheshProf. Khalifa Sifaw Ghenghesh

2. 1. GENUS:1. GENUS: BACILLUSBACILLUS
• Gram +ve bacilli
• Aerobic
• Spore-Forming

3. i.i. Bacillus anthracisBacillus anthracis
• >> Anthrax.
• Large, Square - ended Rods, Arranged in
Chains.
• Non-Motile.
• Spores:
• Capsule:
– Purple Stained >> McFadyan's Method
(Polychrome Methylene Blue).
• Colonies on BA: "Medusa Head Appearance"

4. Bacillus anthracisBacillus anthracis

5. An electron micrograph of spores fromAn electron micrograph of spores from
the Sterne strain ofthe Sterne strain of Bacillus anthracisBacillus anthracis

6. Bacillus anthracisBacillus anthracis McFaydean capsuleMcFaydean capsule
stain, grown at 35stain, grown at 35oo
C, in defibrinatedC, in defibrinated
horse blood.horse blood.

7. DISEASE:
• In Animals: >> Septicaemia.
• In Humans:
i. Cutaneous Anthrax > Malignant pustule
ii. Pulmonary Anthrax (Wool-Sorter'sDisease).
iii. Gastrointestinal Anthrax.

8. Cutaneous AnthraxCutaneous Anthrax

9. Anthrax lesion on the skin of theAnthrax lesion on the skin of the
forearm caused byforearm caused by Bacillus anthracisBacillus anthracis

10. PATHOGENESIS
• Capsule > Invasiveness
– D-glutamic acid
• Exotoxin (Plasmid mediated)
i. Protective Factor (Antigen).
ii. Oedema Factor.
iii. Lethal Factor.
Blocks the Adenyl Cyclase Pathway >
Increases vascular Permeability > Shock

11. LABORATORY DIAGNOSIS:
• Specimens obtained from:
a malignant pustule, sputum, blood.
- Gram stain + fluorescent-antibody stain.
- Motility
- Capsule formation: Sodium bicarbonate
+CO2
- String-of-pearls reaction:
- Mouse test:
- API
>> Demonstration of Abs to the organism:

12. Bicarbonate agar and blood agarBicarbonate agar and blood agar
plate cultures ofplate cultures of Bacillus anthracisBacillus anthracis

13. Negative encapsulation: Blood agar andNegative encapsulation: Blood agar and
bicarbonate agar plate cultures ofbicarbonate agar plate cultures of
Bacillus cereusBacillus cereus

14. • TREATMENT
– Penicillin, Ciprofloxacin
• IMMUNIZATION
–Animals > Live spore vaccine
(Sterne strain)
–Workers at Risk of Exposure >
Anthrax Vaccine Absorbed (AVA) >>
“Alum precipitated toxoid”

15. ii.ii. Bacillus cereusBacillus cereus
• Food Poisoning.
• Clinical Syndromes:
i. Severe Nausea &Vomiting.
ii. Abdominal Cramps & Diarrhoea.

16. PATHOGENICITY:
>> Due to an Enterotoxin.
• Also Causes Disease in Patients with
Underlying Disease.
• TREATMENT:
>> Tetracycline, Erythromycin.
• iii. B. subtilis:
• iv. B. stearothermophilus.

17. 2. GENUS:2. GENUS: CLOSTRIDIUMCLOSTRIDIUM
• Gram +ve bacilli
• Anaerobic,
• Spore Forming
- Spores:

18. Ink Stain of SporulatingInk Stain of Sporulating ClostridiumClostridium--
spores appear clear, vegetative cellsspores appear clear, vegetative cells
darkdark

19. i.i. Clostridium perfringensClostridium perfringens
• Nonmotile
• Spores Not Produced in Ordinary
Media.
• Aerotolerant Anaerobe.
• 5 Types: A - E

20. Gram stain ofGram stain of Clostridium perfringensClostridium perfringens

21. Exudate smear ofExudate smear of
Clostridium perfringensClostridium perfringens

22. Tissue smear ofTissue smear of
Clostridium perfringensClostridium perfringens

23. DISEASE:
• Clostridial Myonecrosis.
• Less Severe Wound Infections.
• Food Poisoning.

24. Patient with gas gangrenePatient with gas gangrene

25. LABORATORY IDENTIFICATION
• In Chopped Meat - Glucose Medium:
• On BA:
• On Egg Yolk Agar:
>> Precipitation (Opalescence).
• Milk Media: Stormy Formation.
• Nagler Reacrion:

26. Blood agar plate withBlood agar plate with Cl. perfringensCl. perfringens
characteristic double zone of hemolysischaracteristic double zone of hemolysis

27. PATHOGENICITY & CLINICAL INFECTION
 α-Toxin: Acts on Lecithin-Containing Lipo-
protein Complexes in the Cell Membrane.
• Predisposing Factors:
i. Trauma with Deep and Lacerated or Crush
Wounds of Muscle Etc.
ii. Require a Reduced Oxygen Tension and
Reduced Oxidation Reduction Potential
for Growth.

28. FOOD POISONING:
• Cl. perfringens Type A >> Enterotoxin.
> Acute Abdominal Pain and Diarrhoea.

29. LABORATORY DIAGNOSIS:
• Important: Diagnosis of Clostridium
Myonecrosis Should Be Rapid and Made on
Clinical Grounds.
i. Direct Smear and Gram Stain of Material
from Deep Within the Wound.
ii. Culture:
Tissue Aspirates or Deep Swabs Taken
from Affected Muscle.

30. TREATMENT:
• Clostridium Myonecrosis:
i. Surgical Removal of All Infected and
Necrotic Tissue.
ii. Antibiotic and Antitoxin Therapy.
iii. Adminstration of Hyperbaric Oxygen.
• Food Poisoning:

31. Clostridia That May Be Associated
with Gas Gangrene:
• Cl. perfringens Type A
• Cl. septicum
• Cl. novyi Type A
• Cl. histolyticum
• Cl. Sordellii

32. Human case of malignant edemaHuman case of malignant edema
caused bycaused by Cl. septicumCl. septicum

33. ii.ii. Clostridium tetaniClostridium tetani
• > Tetanus.
• > Terminal Spores with Drumstick
Appearance.
• > Obligate Anaerobe.

34. Clostridium tetaniClostridium tetani
Gram Positive RodsGram Positive Rods

35. Clostridium tetaniClostridium tetani

36. VIRULENCE FACTORS:
• Tetanus Toxin (Tetanospasmin) >
Neurotoxin.
i. An Intercellular Toxin Released by
Cellular Autolysis.
ii. Inhibits the Release of Inhibitory
Transmitters.
iii. Toxoid.

37. CLINICAL INFECTION & PATHOGENESIS
• "Tetanus is Generalized in Nature".
i. Unimmunized Rural Population.
ii. In Practice: Simple Puncture Wounds >
Nail, Splinter or Thorn.
iii. In Traumatic Wounds > Compound
Fractures, Dental Extractions, Etc.
iv. Tetanus Neonatrum:
v. Postoperative Tetanus:

38. Drawing of a Soldier dying ofDrawing of a Soldier dying of
Tetanus (Opisthotonos)Tetanus (Opisthotonos)

39. A patient presented with facial tetany.A patient presented with facial tetany.
Note the contraction of the masseter andNote the contraction of the masseter and
neck musclesneck muscles

40. LABORATORY DIAGNOSIS:
• > Diagnosis on Clinical Grounds.
TREATMENT:
• i. Antitoxin.
• ii. Debridement of Wound and Removal of
• any Foreign Bodies.
• iii. Pencillin >>> In Large Doses.
• iv. Mild Tetanospasm: >>> Barbiturates.
• v. Severe Cases:
• >>> Use Curare - Like Agents.
• >>> Tracheostomy.
• >>> Careful Control of the Environment.

41. PREVENTION:
> Prompt and Adequate Cleaning of
Wounds.
i. Active Immunity.
ii. Passive Immunity.

42. iii.iii. Clostridium botulinumClostridium botulinum
• > Botulism.
• > Gram +ve, Spore Forming Bacilli.
• > Strict Anaerobe.

43. Gram Stain ofGram Stain of Cl. botulinumCl. botulinum,,
Characteristic Long RodsCharacteristic Long Rods

44. A photomicrograph ofA photomicrograph of
Clostridium botulinumClostridium botulinum type Atype A

45. Blood Agar Plate withBlood Agar Plate with C. botulinumC. botulinum

46. VIRULENCE FACTORS
• Botulinum Toxin >>> Neurotoxin.
–Serologically 8 Toxins >>
A, B, C1, C2, D, E, F & G.
> Affect the Cholinergic System > Blocks
the Release of Acetylcholine (at Points
in Peripheral Nervous System).

47. DISEASE IN HUMANS
1. Food - Borne Botulism:
> Incubation Period: 12-36 Hours to 8 days.
2. Infant Botulism:
LABORATORY DIAGNOSIS
i. Diagnosis Made Clinically.
ii. Detection of Organism or Its Toxin in the
Suspected Food
iii. Samples of Stool or Vomit

48. TREATMENT & PREVENTION
Important: Specific Treatment Should
Begin as Quick as Possible.
>Polyvalent Antitoxin >>> Immediately.
>Physiological Support >>> ICU.
>NEVER Use a Swollen or Defective Can.

49. iv.iv. Clostridium difficileClostridium difficile
• Antibiotic Associated Colitis.
• Produce Two Major Protein Toxins
(A &B).
• Risk Factors:
–Antibiotic Exposure.
–Old Age.

50. Clostridium difficileClostridium difficile

51. Scanning electron micrograph ofScanning electron micrograph of
Clostridium difficleClostridium difficle

52. Intestinal Smear- Close AssociationIntestinal Smear- Close Association
ofof Cl. difficileCl. difficile with Neutrophilswith Neutrophils

53. • Infection Can Be:
–Endogenous or Exogenous.
• Nosocomial Spread: Due to Spores.
LAB DIAGNOSIS:
1. Demonstration of Cytotoxin in Stool.
2. Isolation of the Microorganism.
TREATMENT:
–Discontinuing Treatment.
–Vancomycin.