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Liz's Microbiology Module 2 > Anaerobe Introduction > Flashcards

Flashcards in Anaerobe Introduction Deck (72):
1

A bacterium that is able to replicate w/o O2

Anaerobe

2

Anaerobes often require a ____ redox potential

Low

3

3 types of anaerobes

- Strict obligate anaerobes
- Moderate obligate anaerobes
- Aerotolerant anaerobes

4

3 types of aerobes

- Facultative anaerobe
- Microaerophile
- Obligate aerobe

5

Strict obligate anaerobes
- 2 facts about O2
- 2 examples

- Extremely sensitive; killed by O2
- Clostridium novyi, C. haemolyticum

6

Tolerate moderate exposure to O2; requires an anaerobic environment for growth

Moderate obligate anaerobes

7

Example of a moderate obligate anaerobe

Bacteroides fragilis

8

Able to tolerate exposure to O2; able to grow more slowly in presence of O2, grows best in anaerobic environment

Aerotolerant anaerobes

9

3 examples of aerotolerant anaerobes

- Clostridium tertium
- Clostridium carnis
- Clostridium histolyticum

10

Grows under aerobic and anaerobic conditions; classified as an aerobe

Facultative anaerobes

11

2 examples of facultative anaerobes

- E. coli
- Staphylococcus sp.

12

Need reduced O2 (5%) and increased CO2 for growth

Microaerophiles

13

Example of a microaerophile

Campylobacter sp

14

Requires O2 and usually don't grow under anaerobic conditions

Obligate aerobes

15

2 examples of obligate aerobes

- Pseudomonas spp
- Micrococcus spp

16

Where can anaerobes be found as normal flora?

- Nose
- Mouth
- Oropharynx
- Vagina
- Gastrointestinal tract
- Skin
- Colon
- Soil
- Freshwater/saltwater sediments

17

In the colon, ____ outnumber facultative anaerobes 1000:1

Anaerobes

18

Most anaerobic infections are ____ infections caused by trauma to kin or mucus membranes

Endogenous

19

____ infections are usually by spore forming GPRs and often from soil or ingetsion of contaminated food

Exogenous

20

Infections are most often ____; containing multiple anaerobes

Polymicrobial

21

Factors that predispose a person to anaerobic infections

- Vascular stasis
- Human/animal bite wounds
- Aspiration of oral contents into lungs after vomiting
- Tooth extraction
- Oral surgery
- Puncture of oral cavity
- GI tract surgery or traumatic puncture of bowel
- Genital tract surgery or traumatic puncture of genital tract
- Introduction of soil into a wound

22

List acceptable specimens for anaerobic cultures

- Needle aspirates at active site of infection, tissue, blood (anaerobic blood culture bottle)
- Lower respiratory specimens
- Normally sterile body fluids
- Stool (only for C. difficle)

23

List unacceptable specimens for anaerobic culture

- Voided urine
- Upper respiratory specimens
- Stool (except for C. difficle)
- Vaginal or cervical
- Surface wounds
- Swabs are NOT appropriate (usually)

24

Direct smear microscopic evaluation may present w/ what two signs?

Polymicrobial and pleomorphic

25

Characteristics of myonecrosis (gangrene)

- Absence of inflammatory cells (WBCs)
- Large GPRs
- Gas
- Possible spores

26

All primary plates should have these 3 requirements for anaerobes

- Vitamin K
- Hemin
- Yeast extract

27

Prior to inoculation what should be done to media?

- Stored at room temperature
- Pre-reduced (ensures redox potential stays low)

28

After inoculation, media should be stored in a holding chamber for less than ____ _____ or placed in the anaerobic chamber immediately

1 hour

29

List 5 reducing agents that can be added to media to maintain an anaerobic environment

- Enriched thioglycollate (THIO)
- Chopped meat
- Serum
- Cysteine
- Rumen fluid

30

What does PRAS stand for?

Pre-Reduced Anaerobically Sterilized
- Made w/ no O2 exposure and sealed in O2-free tubes

31

Purpose of ABAP

Anaerobe blood agar plate; non-selective

32

Purpose of PEA

Phenylethyl alcohol; anaerobe blood agar; selective; supports Gram positive

33

Purpose of PV, KV, and LKV

Paromomycin-Vancomycin; Kanamycin-Vancomycin; and Laked Blood Vancomycin; selective isolation of Gram negative anaerobes

34

Purpose of BBE

Bacteroides Bile Esculin; supports growth of bacteroides (selective); media turns black w/ esculin hydrolysis (differential)

35

Ambient air incubation conditions
- % O2 and CO2

21% O2, 0.03% CO2

36

CO2 incubation conditions
- % O2 and CO2

15-21% O2, 5-10% CO2

37

Microaerophilic incubation conditions
- % O2 and CO2

5% O2, 10% CO2

38

Anaerobic incubation conditions
- % O2 and CO2

0% O2, 5-10% CO2

39

List 3 anaerobic systems used in lab to maintain anaerobic conditions

- Anaerobic chamber (glove box)
- Anaerobic jars
- Anaerobic bags and pouches

40

5 advantages of using an anaerobe chamber

- Specimens are never exposed to O2 during set up
- Plate is observed as often as desired
- Incubator option
- Large volume cultures
- Gloves allow for O2 introduction

41

4 disadvantages of using an anaerobe chamber

- Cumbersome
- Airlock
- Space
- Contamination

42

4 anaerobe chamber requirements

- Catalyst
- Desiccant
- Oxidation reduction indicator
- Anaerobic gas (5% H2, 5-10% CO2, 85-95% N2)

43

Removes residual O2, often composed of palladium coated aluminum pellets

Catalyst

44

Used to absorb water; may be a silica gel

Desiccant

45

CO2 needed for the growth of many anaerobes and inert ____ is used as filler for remaining % of anaerobic atomosphere

N2

46

Used to verify daily that anaerobic conditions are maintained, can use indicator such as methylene blue or resazurin

Oxidation reduction indictator

47

Useful for small labs w/ SMALL anaerobe VOLUME

Anaerobic jars

48

Anaerobic jars must be incubated for ____ hours b/c especially susceptible

48 hours

49

Disadvantages of anaerobic jars

Cannot provide all advantages of a chamber, cost analysis over time shows chamber is better, plates must be removed from jar in order to examine and process

50

Advantages of anaerobic bags and pouches

Transport of organisms, plates can be examined w/o removal from bag

51

Gas liquid chromatography
- 2 forms of extraction

1. Ether extraction (most common); short chain volatile acids
2. Chloroform extraction; organic acids non-volatile

52

Media used to grow anaerobes for gas liquid chromatography

PYG broth (peptone yeast extract glucose)

53

Aerotolerance test
- Growth on SBA plate incubated aerobically in ambient air
- Growth on CHOC plate incubated anaerobically in CO2
- No growth on CDC BPA incubated anaerobically

Obligate aerobe

54

Aerotolerance test
- No growth on SBA plate incubated aerobically in ambient air
- Growth on CHOC plate incubated anaerobically in CO2
- No growth on CDC BPA incubated anaerobically

Capnophilic aerobe

55

Aerotolerance test
- Growth on SBA plate incubated aerobically in ambient air
- Growth on CHOC plate incubated anaerobically in CO2
- Growth on CDC BPA incubated anaerobically

Facultative anaerobe

56

Aerotolerance test
- No growth on SBA plate incubated aerobically in ambient air
- No growth on CHOC plate incubated anaerobically in CO2
- Growth on CDC BPA incubated anaerobically

Obligate anaerobe

57

Which form of GLC is most commonly used, volatile vs. non-volatile

Volatile

58

3 tests for proteolysis

- Gelatin hydrolysis
- Milk liquefaction
- Meat digestion

59

Gelatin hydrolysis
- Positive appearance
- Negative appearance

- Pos: liquid
- Neg: solid

60

Milk liquefaction
- Positive appearance
- Negative appearance

- Pos: curds or curdling/digestion
- Neg: no change

61

Meat digestion
- Positive appearance
- Negative appearance

- Strong pos: no individual particles
- Weak pos: some individual particles
- Neg: undigested particles

62

What media is used to anaerobic identification of biochemicals?

Egg yolk agar (EYA)

63

What reactions take place on EYA?

- Lecithinase
- Lipase
- Proteolysis

64

Lipase
- Positive test

- Pos: oil on water appearance

65

Lecithinase
- Positive test

- Pos: opaque appearance around colonies

66

Catalase
- Positive test
- Negative test

- Pos: bubbles
- Neg: no bubbles

67

Indole
- Positive test
- Negative test

- Pos: red
- Neg: no color change

68

Spot indole
- Positive test
- Negative test

- Pos: color change (blue/purple)
- Neg: no color change

69

Esculin
- Positive test
- Negative test

- Pos: black
- Neg: no color change

70

Growth in presence of bile (20%)
- Positive test
- Negative test

- Growth: orange and turbid
- Stimulated growth: opaque yellow
- No growth: no change

71

Urease
- Positive test
- Negative test

- Pos: pink
- Neg: yellow

72

2 newer technologies for identification of anaerobes

- 16S rRNA
- MALDI-TOF