26. Anaerobic Bacteria Most Commonly Isolated from Infection

Question 1

Sensitivity of aerotolerant anaerobes to O2

Answer 1

> 5% O2

Question 2

Anion that is lethal to strict anaerobes

Answer 2

Superoxide (SO) anion

Question 3

Enzyme produced by facultative and aerobic bacteria that converts SO to H2O2 and O2

Answer 3

Superoxide dismutase (SOD)

SO –SOD–> H2O2 + O2

Question 4

System lacking in strict anaerobes to use O2 as terminal electron acceptor

Answer 4

Cytochrome system

Question 5

The means by which energy is produced by strict anaerobes

Answer 5

Fermentation

Question 6

Microscopic characteristics of Peptostreptococcus

Answer 6

Gram-positive cocci in chains

Question 7

The only genus of gram-positive anaerobic cocci involved in disease

Answer 7

Peptostreptococcus

Question 8

Microscopic appearance of Veillonella

Answer 8

Gram-negative cocci

Question 9

Microscopic appearance of Propionibacterium

Answer 9

Gram positive bacillus

Question 10

Resembles Corynebacterium in morphology and arrangement

Answer 10

Propionibacterium

Question 11

Acid produced by Propionibacterium

Answer 11

Propionic acid

Question 12

Causative agent of acne vulgaris (pimples)

Answer 12

Propionibacterium acnes

Question 13

Microscopic appearance of P. acnes

Answer 13

Gram-positive rod/bacillus

Question 14

P. acnes is a common resident in the

Answer 14

Pilosebaceous glands of the human skin

Question 15

P. acnes is highly susceptible to

Answer 15

β-lactam antimicrobial agents (Penicillin G)

Question 16

Microscopic appearance of Actinomyces israelii

Answer 16

Gram-positive bacillus
Tends to form branches
Sometimes with beaded appearance

Question 17

Oxygen requirements of A. israelii

Answer 17

Aerotolerant anaerobe

Question 18

Drugs for A. israelii

Answer 18

Penicillin class

Question 19

Disease caused by A. isralii

Answer 19

Lumpy jaw

Question 20

Gram-positive anaerobic cocci in chains

Answer 20

Peptostreptococcus

Question 21

Gram-positive, non-spore forming, anaerobic rod

Answer 21

Propionibacterium acnes

Question 22

Gram-positive bacillus that may form branches or have a beaded appearance

Answer 22

Actinomyces israelii

Question 23

Gram-positive, non-spore forming, anaerobic bacillus

Answer 23

Propionibacterium

Question 24

Gram-negative anaerobic cocci

Answer 24

Veillonella

Question 25

Appropriate specimens for anaerobic culture

Answer 25

- Blood - Other normally sterile sites (pleural fluid) - lung - dental/sinus - soft tissue - female genital tract - abdomen (aspirate, peritoneal fluid) - bone

Question 26

How to transport tissue specimens for anaerobic culture?

Answer 26

- Anaerobic pouch | - Anaerobic transport tube with medium

Question 27

How to transport fluid or aspirated pus for anaerobic culture?

Answer 27

- express into anaerobic transport vials | - leave in syringe, discard needle and cover with sterile cap

Question 28

How to transport swabs for anaerobic culture?

Answer 28

Must be collected in a sterile surgical field then placed in a special anaerobic swab device

Question 29

Characteristics of primary media used for anaerobic culture

Answer 29

Non-selective Selective Differential

Question 30

All primary media for anaerobic culture must be supplemented with

Answer 30

Vitamin K | Hemin

Question 31

Substances in media that keep O2 levels low

Answer 31

Reducing agents

Question 32

Anaerobic media that selects for gram-negative anaerobic bacilli

Answer 32

Laked kanamycin-vancomycin (KV) blood agar

Question 33

Anaerobic media that is differential/selective for Bacteroides fragilis

Answer 33

Bacteroides bile esculin agar (BBE)

Question 34

Selective/differential media or recognition of C. difficile

Answer 34

CCFA

Question 35

Component in CCFA that inhibits gram-negative bacteria

Answer 35

Cycloserine

Question 36

Component in CCFA that inhibits gram-positive and gram-negative organisms

Answer 36

Cefoxitin

Question 37

Appearance of C. difficile in CCFA

Answer 37

C. difficile ferments fructose resulting in yellow colonies

Question 38

PEA is selective for

Answer 38

Gram-positive cocci and bacilli

Question 39

Nonselective and differential medium that allows detection of lecithinase and lipase

Answer 39

Egg Yolk Agar (EYA)

Question 40

Result of lecithin breakdown in EYA

Answer 40

Opaque precipitate

Question 41

Effect of lipase on EYA

Answer 41

Iridescent sheen on colony surface

Question 42

Phase of bacterial growth that anaerobes are most sensitive to O2

Answer 42

Log/exponential phase

Question 43

Temperature for incubation of anaerobic culture

Answer 43

35-37°C

Question 44

Indicators used to validate anaerobic conditions

Answer 44

Methylene blue | Resazurin indicator

Question 45

Incubation time for anaerobic rapid growers

Answer 45

24 hours

Question 46

Incubation time if Actinomyces is suspected

Answer 46

> 7 days

Question 47

Microscope used to look at tiny anaerobic colonies

Answer 47

Dissecting microscope

Question 48

Anaerobes not inhibited by 20% bile

Answer 48

Bacteroides | Bilophilia

Question 49

Percent of H2O2 used in the catalase test for anaerobes

Answer 49

15% H2O2

Question 50

Antibiotic disks that may be used for presumptive identification of anaerobes

Answer 50

Kanamycin Vancomycin Colistin

Question 51

Sensitivity to O2 of strict anaerobes