Bacillus species

General Information

Vancomycin as empiric therapy for systemic infections.
Food poisoning illness is usually self-limited and usually requires no antimicrobial therapy.

Bacillus species are aerobic spore forming rods that stain gram positive or gram variable.

  • Bacillus organisms are widely distributed in the environment although the primary habitat is the soil. These organisms are usually found in decaying organic matter, dust, vegetable, water, and some species are part of the normal flora. In the hospital setting, outbreaks and pseudo epidemic have been traced to contaminated ventilator equipment, disinfectant (ethyl alcohol), hospital linen and dialysis equipment.

  • The most clinically significant isolate of this group in humans is B. cereus. Sources of B. cereus in food borne outbreaks have been described including rice, meat loaf, turkey loaf, mashed potatoes, beef stew, apples and hot chocolate sold in vending machines.

  • Certain risk factors have been associated with significant Bacillus infections including intravenous drug abuse, sickle cell disease immunosuppression from malignancy, neutropenia and corticosteroid therapy and foreign devices including indwelling intravascular catheters central nervous system shunts, breast implants, and pacemakers.

  • B. anthracis can be classified as a zoonosis, causing infected animals to transmit the disease to humans. It is also an bacteria associated with bioterrorism.

  • Blood culture contaminant

  • Neonatal bacteremia and meningitis

  • Self limited food poisoning

  • Localized infections related to trauma (e.g. ocular infections)

  • Deep seated soft tissue infections

  • Systemic infections (e.g. meningitis, endocarditis, osteomyelitis, and bacteremia), rare

  • Fulminant eye infections are widely recognized complications of non anthrax Bacillus infections most commonly B. cereus.

B. anthracis is associated with four clinical syndromes in humans based on the portal of entry:
1. Cutaneous- the most common form (95%), causes a localized, inflammatory, black, necrotic lesion (eschar). Most often the sore will appear on the face, neck, arms, or hands. Development can occur within 1-7 days after exposure.
2. Inhalation- a rare but highly fatal form, is characterized by flu-like symptoms, chest discomfort, diaphoresis, and body aches. Development occurs usually a week after exposure, but can take up to two months.
3. Gastrointestinal- a rare but also fatal (causes death to 25%) type, results from ingestion of spores. Symptoms include: fever and chills, swelling of neck, painful swallowing, hoarseness, nausea and vomiting (especially bloody vomiting), diarrhea, flushing and red eyes, and swelling of abdomen. Symptoms can occur within 1-7 days of exposure.
4. Injection- symptoms are similar to those of cutaneous anthrax, but injection anthrax can spread throughout the body faster and can be harder to recognize and treat compared to cutaneous anthrax. Symptoms include, fever, chills, a group of small bumps or blisters that may itch, appearing where the drug was injected. A painless sore with a black center that appears after the blisters or bumps. Abscesses deep under the skin or in the muscle can develop where the drug was injected.