T2: Anaerobic Bacteriology Introduction

Question 1

a bacterium that is able to replicate without oxygen

Answer 1

An anaerobe

Question 2

Anaerobes often require a ______ redox potential

Answer 2

low

Question 3

Three types of Anaerobes

Answer 3

1. Strict obligate anaerobes
2. Moderage obligate anaerobes
3. Aerotolerant anaerobes

Question 4

Three types of Aerobes

Answer 4

1. Facultative anaerobe
2. Microaerophile
3. Obligate aerobe

Question 5

Strict obligate anaerobes

- 2 facts about oxygen

Answer 5

• Extremely oxygen sensitive

- Killed by oxygen

Question 6

Strict obligate anaerobes

- 2 examples

Answer 6

Clostridium novyi and C. haemolyticum

Question 7

Tolerate moderate exposure to Oxygen, Require an anaerobic environment for growth

Answer 7

Moderate Obligate Anaerobes

Question 8

Example of a moderate obligate anaerobe

Answer 8

Bacteroides fragilis

Question 9

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

Answer 9

Aerotolerant anaerobes

Question 10

Three examples of Aerotolerant anaerobes

Answer 10

Clostridium tertium, C. carnis, and C. histolyticum

Question 11

grow under aerobic or anaerobic conditions, classified as an aerobe

Answer 11

Facultative anaerobes

Question 12

two examples of facultative anaerobes

Answer 12

E. coli and Staphylococcus spp

Question 13

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

Answer 13

microaerophiles

Question 14

Example of a microaerophile

Answer 14

Campylobacter spp

Question 15

Require oxygen and usually don’t grow under anaerobic conditions

Answer 15

Obligate aerobes

Question 16

two examples of obligate aerobes

Answer 16

Pseudomonas spp and Micrococcus spp

Question 17

Where can anaerobes be found as normal flora?

Answer 17

Nose, Mouth, oropharynx, vagina, gastrointestinal tract, skin, colon, soil, and freshwater/saltwater sediments

Question 18

In the colon ______ outnumber facultative anaerobes 1000:1

Answer 18

anaerobes

Question 19

Most anaerobic infections are _________ infections caused by trauma to skin or mucous membranes

Answer 19

Endogenous

Question 20

_______ infections are usually by spore forming GPRs and often from soil or ingestion of contaminated food

Answer 20

Exogenous

Question 21

Infections are most often ________ ; containing multipe anaerobes

Answer 21

Polymicrobic

Question 22

Factors that predispose a person to anaerobic infection

Answer 22

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

Question 23

List acceptable specimens for anaerobic culture

Answer 23

Needle aspirates at active site of infection, tissue, blood (anaerobic blood cult. bottle), lower respiratory specimens, normally sterile body fluids, Stool (only for C. diff)

Question 24

Unacceptable specimens for anaerobic culture

Answer 24

voided urine, upper respiratory specimens, stool (except for C. diff), vaginal or cervical, surface wounds; swabs are NOT appropriate (usually)

Question 25

Direct smear microscopic evaluation may present with what two signs?

Answer 25

polymicrobial and pleomorphic

Question 26

Characteristics of Myonecrosis (gangrene)

Answer 26

absence of inflammatory cells (WBCs), Large GPRs, gas, and possible spores

Question 27

All primary plates should have these 3 requirements for anaerobes

Answer 27

1 vitamin K 2 hemin 3 yeast extract

Question 28

Prior to inoculation what should be done to media?

Answer 28

1 Stored at room temp | 2 Pre-reduced (ensures redox potential stays low)

Question 29

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

Answer 29

1 hour

Question 30

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

Answer 30

Enriched thioglycollate (THIO), chopped meat, serum, cysteine, and rumen fluid

Question 31

What does PRAS stand for?

Answer 31

Pre-Reduced Anaerobically Sterilized; made with no oxygen exposure and sealed in oxygen free tubes

Question 32

Purpose of ABAP

Answer 32

Anaerobe blood agar plate; non-selective

Question 33

Purpose of PEA

Answer 33

Phenylethyl alcohol, anaerobe blood agar, selective, supports Gram Positive

Question 34

Purpose of PV, KV, and LKV

Answer 34

Paromomycin-Vancomycin, Kanamycin-Vancomycin, and Laked Blood Vancomycin; Selective isolation of gram negative anaerobes

Question 35

Purpose of BBE

Answer 35

Bacteroides Bile Esculin; supports growth of Bacteroides (selective), media turns black with esculin hydrolysis (differential)

Question 36

Incubation Conditions | -Ambient Air

Answer 36

21% O2, 0.03% CO2

Question 37

Incubation Conditions | -CO2

Answer 37

15-21% O2, 5-10% CO2

Question 38

Incubation Conditions | -Microaerophilic

Answer 38

5% O2, 10% CO2

Question 39

Incubation Conditions | -Anaerobic

Answer 39

0% O2, 5-10% CO2

Question 40

List 3 anaerobic systems used in lab to maintain anaerobic conditions

Answer 40

1 Anaerobic Chamber (glove box) 2 Anaerobic Jars 3 Anaerobic Bags and Pouches

Question 41

Advantages of using an anaerobe chamber (5)

Answer 41

Specimens never exposed to oxygen during set up, plate observed as often as desired, incubator option, large volume cultures, gloves allow for less Oxygen introduction

Question 42

Disadvantages of using an anaerobe chamber (4)

Answer 42

Cumbersome, airlock, space, contamination

Question 43

Anaerobe Chamber requirements (4)

Answer 43

Catalyst, desiccant, oxidation reduction indicator, and anaerobic gas (5% H2, 5-10% CO2, and 85-95% N2)

Question 44

removes residual O2, often composed of palladium coated aluminum pellets

Answer 44

catalyst

Question 45

used to absorb water

Answer 45

desiccant

Question 46

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

Answer 46

N2

Question 47

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

Answer 47

Oxidation Reduction Indicator

Question 48

useful for small labs with SMALL anaerobe VOLUME

Answer 48

Anaerobic jars

Question 49

Anaerobic jars must be incubated for ______ hours because especially susceptible

Answer 49

48 hours

Question 50

Disadvantages of Anaerobic Jars

Answer 50

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

Question 51

Anaerobic bags and pouches advantages

Answer 51

Transport of organisms, plates can be examined without removal from bag

Question 52

Gas Liquid Chromatography 2 forms of extraction

Answer 52

1 Ether Extraction (Most common); short chain volatile acids | 2 Chloroform Extraction; organic acids, non-volatile

Question 53

Media used to grow anaerobes for gas liquid chromatography

Answer 53

PYG Broth (peptone yeast extract-glucose)

Question 54

To detect fermentation large tubes contain ______ or ________ biochemical test media; reactions measure the _____ with a _______

Answer 54

PRAS or Non-PRAS; pH; Probe

Question 55

List 3 tests for Proteolysis

Answer 55

1 Gelatin Hydrolysis 2 Milk Liquefaction 3 Meat Digestion

Question 56

Two newer technologies that are very reliable for ID of bacteria including anaerobes

Answer 56

16S rRNA sequencing and MALDI-TOF