Bacilli spp

Question 1

Category A bioterrorism agent; soil-isolate contracted by animals or exposed workers (industrial, military, public health personnel)

Answer 1

Bacillus anthracis

Question 2

B. anthracis capsule composition

Answer 2

Poly-D-glutamic acid

Question 3

Plasmid-borne anthrax toxins and components

Answer 3

Lethal toxin (LT) and Edema toxin (ET) composed of Protective antigen (PA), lethal factor, and edema factor

Question 4

Disease forms caused by B. anthracis

Answer 4

Cutaneous anthrax (black eschar), Pulmonary anthrax (Woolsorter’s disease), Gastrointestinal anthrax (toxemia, sepsis), Injectional anthrax (septic shock in drug users)

Question 5

Macroscopic appearance of B. anthracis on BAP

Answer 5

Gray, flat, non-hemolytic, comet-tail/Medusa-head or ground-glass colonies

Question 6

Microscopic appearance of B. anthracis

Answer 6

Large gram-positive bacilli in chains resembling bamboo-square

Question 7

Spore-inducing techniques for B. anthracis

Answer 7

Heat or alcohol shock treatment; Growth in TSI, Urea, NA with manganese sulfate, or bicarbonate medium

Question 8

Selective media and presumptive tests for B. anthracis

Answer 8

PLET agar; 10 U Penicillin susceptibility test (String of pearls appearance), PCR (capBCA capsule gene)

Question 9

Fried rice bacillus and blood bank contaminant

Answer 9

Bacillus cereus

Question 10

Diarrheal type of B. cereus symptoms and toxins

Answer 10

Diarrhea, abdominal pain; Hemolysin BL (HBL), Nonhemolytic enterotoxin (Nhe), Cytotoxin K (CyK)

Question 11

Emetic type of B. cereus symptoms and toxin

Answer 11

Profuse vomiting; Cereulide enterotoxin

Question 12

Infections caused by B. cereus

Answer 12

Diarrhea, vomiting, posttraumatic eye infections, endocarditis, bacteremia, progressive endophthalmitis

Question 13

Growth characteristics of B. cereus on BAP

Answer 13

Large, feathery, spreading beta-hemolytic colonies; wide zone of clearing on egg yolk agar (lecithinase positive)

Question 14

Food poisoning caused by B. cereus sample of choice

Answer 14

Food

Question 15

B. cereus heat shock treatment

Answer 15

70°C for 30 mins or 80°C for 10 mins

Question 16

Causative agent of food poisoning in rehydrated foods

Answer 16

Bacillus cytotoxicus

Question 17

Symptoms and toxin of B. cytotoxicus

Answer 17

Severe food poisoning; Cytotoxin K, enterotoxin

Question 18

Growth characteristics of B. cytotoxicus on BAP

Answer 18

Large, feathery, spreading beta-hemolytic colonies

Question 19

Unknown virulence factors causing opportunistic infections and food poisoning

Answer 19

Bacillus circulans, B. firmus, B. licheniformis, B. subtilis, B. thuringiensis

Question 20

Insecticidal use of B. thuringiensis

Answer 20

Cereulide toxin in insecticides and pesticides

Question 21

Opportunistic infections caused by B. subtilis

Answer 21

Eye infections among drug users

Question 22

Colony characteristics of B. subtilis on BAP

Answer 22

Large, flat, dull, ground-glass, beta-hemolytic, may be pink/yellow/orange pigmented colonies

Question 23

Unique feature of B. thuringiensis

Answer 23

Parasporal crystals/Insecticidal proteins

Question 24

Opportunistic infections and food poisoning caused by Paenibacillus polymyxa

Answer 24

Unknown virulence factors

Question 25

Growth characteristics of Paenibacillus polymyxa on BAP

Answer 25

Large, moist blister colonies with ameboid spreading in young cultures; wrinkled old cultures; non-hemolytic

Question 26

Positive wide-zone lecithinase, capsule, Penicillin G sensitive

Answer 26

Bacillus anthracis

Question 27

Positive wide-zone lecithinase, motility, hemolysis, gelatinase, Penicillin G resistant

Answer 27

Bacillus cereus