Bacillus anthracis

B. anthracis general characteristics

Rods w/ right angle ends

Singly or in pairs

Central oval spore

Nonmotile

B. anthracis transmission to humans

Skin contact w/ contam animal products - malignant pustule

Ingestion of contam food - gastroenteritis

Inhalation of contam dust - Woolsorter’s disease

B. anthracis virulence factors

Capsule

Anthrax exotoxin

Anthrax exotoxin components (3)

Protective antigen - adherence

Edema factor - generates camp, antiphagocytic

Lethal factor - kills macrophage

Markers of cutaneous anthrax

Painless dark pustule/black eschar

Face and neck edema

Pulmonary anthrax is a.k.a.

Woolsorter’s disease

Woolsorter’s disease pathogenesis

1. Inhalation

2. Inflammation of lymph nodes

3. Hemorrhagic necrosis → respi distress, cyanosis

4. Death within 24h

Test to demonstrate B. anthracis capsule

Bicarbonate agar - mucoid colony if (+) capsule

B. anthracis morphology on BAP

Medusa head

This test differentiates B. anthracis from B. cereus

Agar w/ bacteriophage

Lysis - anthrax

No lysis - cereus

B. anthracis treatment

Ciprofloxacin or Doxycycline

Additional: Rifampin, Vanco, Penicillin, Imipinem

B. anthracis control

Bury dead animals deep - prevent spores

Gas sterilize animal hides and wools

B. anthracis vaccines

Animals: Live spore vaccine (Stearne strain)

Man: Killed Spore Vaccine

B. anthracis BAP appearance

Cut glass

alpha/gamma hemolytic

gray-white tenacious colonies

medusa head