Bacillus anthracis

Note: Biohazard level III pathogen. Alert the laboratory if this organism is suspected.

Gram Stain

• Gram positive bacilli (aerobic)

Clinical Significance

These organisms are distributed in nature, especially soil environments.

B. anthracis is an obligate pathogen of animals/humans and is the cause of anthrax which can manifest in different forms including cutaneous, intestinal and inhalational infections.

Usual Susceptibility Pattern

B. anthracis is typically susceptible to penicillin/ampicillin, doxycycline, and vancomycin.

Cephalosporins, TMP/SMX, and macrolides do not have reliable activity.

Clindamycin and quinolone resistance can be considerable depending on geographical location.