MISCELLANEOUS BACTERIA (Anaerobes)

Question 1

Bacteria described as having terminal spores (“lollipop” or “tennis racket” appearance)

Answer 1

Clostridium tetani

Question 2

C. tetani produces a neurotoxin called _______ which causes ______, manifested as _______.

Answer 2

C. tetani produces a neurotoxin called tetanospasmin which causes tetanus, manifested as spastic paralysis.

Question 3

Classic symptoms of C. tetani infection:

Answer 3

• Lock jaw (trismus)
• Opisthotonos - arching of the back

Question 4

Ubiquitous organism; causes the disease botulism (“floppy baby syndrome” in infants)

Answer 4

Clostridium botulinum

Question 5

Manifestation of botulism:

Answer 5

Flaccid paralysis

Question 6

Most cases of botulism are due to ingestion of food in which C. botulinum has grown and produced the botulinum toxin - commonly found in _______ (in adults) and in ________ (in babies)

Answer 6

• Contaminated canned foods (in adults)
• Contaminated honey (in babies)

Question 7

Clostridium that causes gas gangrene

Answer 7

Clostridium perfringens

Question 8

What is the toxin present in C. perfringens? it destroys muscle tissue and causes hemolysis; degrades phospholipids in cell membranes; Phospholipase acts on lecithin (lecithinase)

Answer 8

Alpha toxin

Question 9

What toxin produced by C. perfringens that is a common cause of food poisoning (usually from undercooked meat)

Answer 9

Enterotoxin

Question 10

Characteristic hemolysis of Clostridium perfringens on blood agar:

Answer 10

Double zone hemolysis/ Target hemolysis

Question 11

Test for C. perfringens; Inhibition by anti-perfringens antitoxin of the precipitate around growth on egg yolk agar

Answer 11

Nagler’s test

Question 12

Clostridium that causes pseudomembranous colitis in patients undergoing prolonged antibiotic therapy (destroys normal flora of the gut)

Answer 12

Clostridium difficile

Question 13

what are the toxins produced by C. difficile and their effects?

Answer 13

1. Toxin A: Enterotoxin –> watery diarrhea
2. Toxin B: Cytotoxin –> Cell necrosis/ fibrin deposition

Question 14

Bacteroides fragilis grows in ___ bile and ________.

Answer 14

Grows 20% bile and hydrolizes esculin

Question 15

Bacteroides fragilis is resistant to:

Answer 15

penicillin

Question 16

Thin gram (-) rods with tapered ends; often in pairs end-to-end;

Answer 16

Fusobacterium nucleatum

Question 17

Differentiate B. fragilis and F. nucleatum

Answer 17

B. fragilis
- Grows in 20% Bile
- Does not produce butyric acid

F. nucleatum
- No growth in 20% Bile
- Produces a large amount of butyric acid

Question 18

Gram (+) non-sporulating anaerobic rods; clusters into thin branching long filaments (resembling fungi)

Answer 18

Actinomyces spp.

Question 19

Colony characteristics of Actinomyces spp.

Answer 19

Heaped, rough, lobate resembling “molar tooth”

Question 20

Causative agent of human actinomyces infection:

Answer 20

Actinomyces israelii

Question 21

Clinical picture of human actinomyces infection:

Answer 21

“wooden” or lumpy lesions