Term
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Definition
| organism that will only grow in an anaerobic environment (0% O2) |
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Term
| Microaerotolerant anaerobe |
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Definition
| organism that can grow in a microaerophilic environment (<5% O2) but not a CO2 environment (15% O2) or room air (21% O2) |
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Term
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Definition
| Capable of growing in an atmosphere containing room air, but grows better under anaerobic conditions |
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Term
| What are the predominant type of flora in the body? |
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Definition
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Term
| Where are anaerobes commonly found as normal flora? |
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Definition
- Skin
- Mucous Membranes
- Lower GI tract
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Term
| What is the most common way a person obtains an anaerobic infection? |
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Definition
| NF spreading from normal sites to an adjacent normally sterile site. |
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Term
| Endogenous anaerobe infection |
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Definition
| Spread from nearby NG sites as a consequence of a break in a barrier like a membrane |
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Term
| Exogenous anaerboic infection |
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Definition
| Comes from outside the body |
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Term
| Characteristics of Endogenous anaerobic infections. |
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Definition
- Spread from self's NF to normal sterile body site.
- Usually polymicrobial infection
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Term
| Characteristics of Exogenous anaerobic infections. |
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Definition
- Relatively uncommon
- Monomicrobial
- Most caused by spore-forming Clostridium spp. (botulism, tetanus, food-borne gastroenteritis, gas gangrene)
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Term
| What are some clinical diseases caused by Clostridium spp.? |
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Definition
- Botulism
- Tetanus
- Food-borne gastroenteritis
- Gas gangrene
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Term
| What is the best and worst specimen for isolation of anaerobes? What specimen in not acceptable? |
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Definition
Best: tissue, aspirates (normally sterile fluid)
Worst: swabs
Not acceptable: Contaminated with NF |
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Term
| What special transport media is used for anaerobes for liquids/solids? |
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Definition
Liquids: Anatrans
Solids or swabs: Cary Blair |
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Term
| What kind of microscopic morphologies are suggestive of an anaerobe? |
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Definition
- tiny GPC
- fusiform GNB
- bipolar staining GNB
- large GPB
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Term
| What are the 4 standard plate media used for isolation of anaerobes? And broth? |
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Definition
- Anaerobic Brucella (hemin, Vit K, and yeast extract)
- PEA
- LKV
- BBE
- Broth: CMG
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Term
| What is the purpose of PEA media in isolating anaerobes? |
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Definition
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Term
| What is the purpose of LKV media in isolation of anaerobes? |
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Definition
| Selective for anaerobic GNB |
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Term
| What is the purpose of BBE agar in the isolation of anaerobes? |
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Definition
| Selective for Bacteroides fragilis (a common GNB) |
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Term
| What is the purpose of CMG (chopped meat glucose) broth in the isolation of anaerobes (2)? |
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Definition
- Pick up low numbers of organisms
- Serves as backup in case anaerobic conditions are compromised on plates
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Term
| How long must anaerboic cultures be incubated before reading? Why? |
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Definition
24 hours
Very susceptible to O2 while in log phase
(Most don't show growth until 48 hour anyway) |
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Term
| If a mixed plate of anaerobes and aerobes is suspected, what should be done? |
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Definition
| Subculture possible anaerboes to Brucella (anaerobic) and BAP (aerobic) |
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Term
| What are four ways anaerobes can be ID'd? |
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Definition
- Rapid Tests
- Specialized media for detection of enzymes
- Commercially available ID systems based on pre-formed enzymatic reactions
- Metabolic end product analyses by gas liquid chromatography
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Term
| Is Clostridium deficile normal flora? |
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Definition
| Yes, in 20% of the population. |
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Term
| What is the population most commonly infected with Clostridium deficile infections? |
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Definition
| Hospitalized patients (on certain antimicrobials) |
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Term
| What are the clinical diseases of Clostridium deficile? |
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Definition
- Antibiotic-associated diarrhea (very water diarrhea)
- Pseudomembrane of the colon
- Megacolon (rupture)
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Term
| What toxins does C. difficile produce? How are they detected? |
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Definition
Toxin A - ELISA
Toxin B - ELISA and PCR |
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Term
| What medium is used to isolate C. deficile? What does it inhibit? |
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Definition
| CDSA - inhibits many GI anaerobes |
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Term
| What do C. difficile colonies look like on CDSA medium? |
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Definition
Yellow, flat, fringy, ground glass colonies |
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Term
| What is the microscopic morphology of C. defficile? |
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Definition
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Term
| What is the rapid confirmatory test for C. defficile? |
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Definition
| "Pro" - spot disk test (positive) |
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Term
| What 2 requirements must be met before diagnosing C. defficile? |
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Definition
- Positive toxin test
- Ioslation of the organisms
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Term
| What is the treatment for C. defficile? |
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Definition
- Metronidazole or Vancomycin
- Stop other antibiotics
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