Anaerobic Organisms

Question 1

An aerobic bacterial wound culture was reported. What organisms can you not rule out?

Answer 1

Clostridium

Question 2

Organisms that can produce spores include:
A) Bacillus (aerobic) and bacteroides (anaerobic)
B) Bacillus (anaerobic) and Bacteroides (Aerobic)
C)Bacillus (aerobic) and Clostridium (anaerobic)
D) Bacilus (anaerobic) and clostridium (aerobic)

Answer 2

C

Question 3

An organism causing pseudomembranous colitis after prolonged antibiotic use is most consistent with:

Answer 3

Clostridium difficle

Question 4

Infections caused by which anaerobic organisms are confirmed via culture?

Answer 4

Bacteroides fragilis and Clostridium perfringens

Question 5

The Gram stain reaction and morphology of the most common anaerobic organism isolated in the clinical laboratory is:

Answer 5

gram-negative bacilli- Bacteroides fragilis

Question 6

An organism causing gas gangrene in which wound direct specimen Gram stains will often lack white blood cells due to cell lysis is:

Answer 6

Clostridium perfringenes

Question 7

Organism leading to Flaccid paralysis leads to Resp paralysis (death); Wounds (rare)

Answer 7

Clostridium botulinum

Question 8

Gram stain of Clostridium sp.

Answer 8

Gram positive bacilli- most produce spores when stressed

Question 9

What is widely distributed in soil and water and associated with home canning and honey?

Answer 9

Clostridium botulinum

Question 10

Virulence factor of Clostridium botulinum

Answer 10

Neurotoxin- inactivates proteins that regulate release of Ach

Question 11

How is Clostridium botulinum identified in the lab

Answer 11

Confirmed via toxin detection Usually performed by public health lab

Question 12

Most frequently isolated clostridium sp.

Answer 12

perfringens

Question 13

Virulence factor of Clostridium perfringens

Answer 13

Alpha toxin: lyses RBCs, [;ate;ets, WBCs, tissue; hepatic toxicity; myocardial dysfunction

Question 14

Eating what type of food can put you at risk of getting Clostridium perfringens enterotoxin. How would you treat?

Answer 14

Meat products: beef, chicken, turkey. No treatment necessary.

Question 15

Clostridium perfringens reatment

Answer 15

Debridement, excision or amputation of dead tissue. Antibiotic therapy: penicillin (high dose) plus clindamycin.
-Hyperbaric oxygen- effectiveness inconclusive.

Question 16

What anaerobic organism is normal flora of mouth, Upper respiratory tract, GI tract, and urogenital tract that can cause infect wounds, abscesses, bacteremia, other infections?

Answer 16

Bacteroides fragilis group

Question 17

How is clostridum butulinum confirmed?

Answer 17

Via toxin detection- usually performed in public health lab

Question 18

How is clostridium perfringens confirmed?

Answer 18

Via anaerobic culture. Gas gangrene culture shows necrotic tissue with large rectangular rods with lack of inflammatory cells.

Question 19

How is clostridium tetani confirmed? Treatment?

Answer 19

Via clinical symptoms. Debridement, Metro, Antitoxin.

Question 20

How is clostridium difficile confirmed? Treatment?

Answer 20

Via toxin in stool (Metro and vanco)

Question 21

How is Bacteroides fragillis confirmed? How would you treat?

Answer 21

Via anaerobic culture- treat with beta lactam and beta lactamase inhibitor (Metronidazole and Imipenem)

Question 22

How do anaerobes obtain energy?

Answer 22

Fermentation

Question 23

T/F: Strict obligate anaerobes can cause human infections.

Answer 23

False: Not associated with humans. Cant be cultured because oxygen is toxic. Moderate obligate anaerobes cause human infections.