Bacillus

1
Bacillus

• Saprophytic
• B.cereus
• B.subtilis
• B.megaterium
• B.Circulans
• Pathogenic
• B.anthracis

2
B.anthracis

• It is aerobic Gve, large ,square-ended
  (rectangular)bacilli with oval central spores,
  non motile, capsulated, arranged singly or in
  short chains, the organism grows well on blood
  agar. Hemolysis is uncommon with B.anthracis but
  common with saprophytic bacilli. If the colonies
  are looked under microscopic lens. They will
  appear as apiece of curled hair. The colony is
  composed of continuous chain of bacilli. The
  colony is described as "Medusa- head", this
  character is useful for DX identification of
  the colony. By G.stain, some spores will be seen
  in between the vegetative cells and these spores
  appear as empty spaces with out stain. The spores
  usually resist boiling some chemicals dry
  heat of 140C? but they are destroyed by
  autoclaving (moist heat) for 15 min.

3
Biochemical reaction

• Glucose , sucorose maltose are fermented with
  production of acid only. The bacilli are
  catalaseve and reduce nitrates to nitrites.

4
Antigens

• C.W Ag
• Capsular Ag.
• Somatic Ag

5
Types of anthrax

• There are three clinical types of anthrax based
  on the route of infection
• 1-Skin or coetaneous anthrax (Malignant pustule)
• 2- Respiratory or pulmonary anthrax (wool
  sorters' disease)
• 3- Intestinal anthrax (rare) in primitive or
  poor society. Eat meat of infected
• animals

6
Pathogenesis

• Anthrax is a zoonosis. The portal of entry is the
  respiratory tract, a cut in skin or the mouth
  when spores enter the human body, they lodge in
  one place starts to germinate they will produce
  toxins enzymes till hemorrhage oedema are
  produced .
• In susceptible persons, the bacilli resist F
  spread to lymphatic to the blood where they
  multiply freely in blood tissues. While in
  resistant people, there is more leukocyte
  response with F and decapsulation of the
  microorganisms.
• Once the organism looses its capsule, it will die
  easily because it looses its virulence.

7
Clinical findings

• Skin anthrax a papule first develops within
  12-36 hrs after entry of the organisms or spores
  through a scratch. This papule rapidly changes
  into a vesicle, then a pustule, and finally a
  necrotic ulcer from which the infection may
  disseminate. Giving rise to septicemia.
• Respiratory anthrax In inhalation anthrax ,
  early manifestations may be mediastinitis,
  sepsis, meningitis, or hemorrhagic pulmonary
  edema. Hemorrhagic pneumonia with shock is a
  terminal event.
• Intestinal anthrax Ingestion of spores cause
  severe enteritis accompanied by bloody diarrhea
  with high fatality.
• Hence, all types of anthrax, if not treated in
  time, progress to septicemia and death occurs
  from overwhelming infection.

8
Lab DX

• Specimens Pus, Blood, swabs, fluid, sputum
• Smear
• Culture
• 1-Medusa head
• 2-fir tree appearance
• 3-curled hair
• Animal inoculation
• Serodiagnosis

9
Treatment

• B.anthracis
• Pencillin, ciprofloxacin, erythromycin,
  tetracycline
• Other Bacillus spp
• Vancomycin, ciprofloxacin