Bacillus

Question 1

Bacillus spp.

Answer 1

• Aerobic
  -non acid fast
• Spore forming
• catalase positive
• non branching
• 5% blood sheep agar, blood culture media, nutrient broths, PEA and CA media

Question 2

Clostridium spp.

Answer 2

• Anaerobic
• non acid fast
• spore forming
• catalase negative
• non branching

Question 3

Cutaneous Anthrax

Answer 3

• most human infections
• endosperm’s come in through break in the skin
• obtained from contact with animal products
• 2-6 incubation
• ring of vesicles appear that develop into an ulcer (eschar) on the skin
• no fever, fatal if lesions are on face and neck (obstructed airway)
• mortality rate of 1%

Question 4

GI Anthrax

Answer 4

• ingestion of endospores
• eating raw or undercooked meat
  1. Oral-pharyngeal lesions: sore throat , lymphadenopathy, edema of throat and chest
  2. GI lesions: nonspecific symptoms that progress to abdominal pain, nausea, vomiting, anorexia, fever, bloody diarrhea, and hematemesis
• mortality higher than cutaneous

Question 5

Inhalation (Wool-sorters Anthrax)

Answer 5

• inhalation if endospores
• most deadly
• exposure to endospores from handling infected animal hides, hair, or fibers
• macrophages ingest these in the lungs and transport them to the lymph nodes
• flu like disease: fever, chills, fatigue, cough, nausea, vomiting
  -then progression to respiratory distress, edema, cyanosis, shock, and death.
• widened mediastinum

Question 6

Injectional Anthrax

Answer 6

• happens through contaminated drugs, usually heroin (animal skins used to move drugs)
• skin site is bruised, no eschar
• leads to systemic dissemination and septic shock
  -not seen in US

Question 7

Anthracis Presumptive Identification

Answer 7

• large, non-hemolytic colony that stands up like a beaten egg (positive tenacity test)
• gram stain: large, gram positive rods
• catalase positive
• nonmotile

Question 8

Anthracis Confirmatory Identification

Answer 8

• detection of antibodies by indirect hemagglutination and enzyme linked immunosorbent assays
  -Multilocus Sequence Typing (MLST)
• DNA microarrays
• MALDI-T identifies PA, EF, and LF proteins
  -PCR is most rapid test: detects several targets on the chromosome and virulence plasmids (which code for the biosynthesis of the capsule)

Question 9

Environment Location comparison

Answer 9

Both B. cereus and B. anthracis are found in soil

Question 10

Mode of Transmission comparison

Answer 10

B. Anthracis:
- injectional, inhalation, GI, and Cutaneous

B. Cereus
- Trauma
- food borne illness (meats, vegetables, rice), immunocompromised, skin infections or systemic (endocarditis or septicemia), urinary or respiratory tract, HAI, contaminated drugs

Question 11

Morphology Comparison

Answer 11

B. Cereus:
- beta hemolytic
- large feathery
- motile, non encapsulated

B. Anthracis
- gray, flat, irregular swirling projections “Medusa head”, ground glass appearance
- non-hemolytic (gamma)
- stands up like a beaten egg (positive tenacity test)
-non motile
- gram stain: large, positive rods
- catalase positive

Question 12

Specimen Processing Comparison

Answer 12

• Heat or alcohol shock prior to plating and selects for spore forming bacilli

Anthracis
- leak proof primary container and secondary container prior to antibiotic therapy
- vesicular fluid from eschar, blood cultures, stool, CSF, pleural fluid, tissue, ascites fluid, sputum, bronchitis biopsy, or serum
- use formaldehyde prior to disposal: must alert cdc within 7 days upon ID

Question 13

Bioterrorism select agent comparison

Answer 13

B. Anthracis
- category A agent: those presenting the highest risk to public health and national security because they are easily transmitted from person to person and have high mortality rates

B. Cereus
- not a select agent

Question 14

Biohazard precautions comparison

Answer 14

• wash hands
• wear gloves
• mask, gown, eye protection
• take care to prevent injuries
• dispose of single use items properly
• ensure the reusable equipment is sterilized