Idit Exam 3 - Steinauer - Anaerobes

Front 1

What are the two kinds of anaerobes?

Back 1

1. Strict anaerobes - will die in presence of O2
2. Aerotolerant - will survive temporarily in O2

Front 2

Why can't anaerobes metabolize oxygen?

Back 2

Don't have cytochrome systems

Front 3

Since they don't metabolize oxygen, how do anaerobes get energy?

Back 3

Fermentation

Front 4

What is a thioglycollate broth?

Back 4

Contains sodium thioglycolate that is a reducing agent that consumes oxygen

Allows growth of anaerobes

Front 5

Can an obligate anaerobe grow in thioglycollate broth?

Back 5

Only at the top where O2 is present

Front 6

Can facultative organisms grow in thioglycollate broth?

Back 6

Can grow throughout but more concentrate on the top where O2 is present

Front 7

Can aerotolerant anaerobes grow in thioglycollate broth?

Back 7

Everywhere evenly

Front 8

Can strict anaerobes grow in thioglycollate broth?

Back 8

No growth at the top layer

Evenly elsewhere

Front 9

Why ix oxygen toxic to anaerobes?

Back 9

Some species may not have Superoxide Dismutase or Catalase --> cannot get rid of toxic metabolites

Oxygen's high redox potential can react with iron-sulfur centers of sensitive enzymes -->non functional enzyme

Front 10

What is autoassasination

Back 10

Where metabolism generates oxygen products that are toxic to the anaerobic microbe

Front 11

2 ways you can culture anaerobes?

Back 11

1. Use reducing agent medium
2. Culture in a chamber without oxygen

Front 12

6 endogenous anaerobes?

Back 12

1. Fusobacterium
2. Porphyromonas
3. Prevotella
4. Actinomyces
5. Propionibacterium
6. Peptostreptococcus

Front 13

1 exogenous anaerobe?

Back 13

Clostridium

Front 14

3 anatomic sites with high anaerobes:aerobes ratio?

Back 14

1. Gingival crevices
2. Terminal ileum/colo
3. Female genital tract

Front 15

Bacteriodes - shape and gram? Where does it colonize?

Back 15

Gram negative coccobacillus

Colon, oral and vagina flora

Front 16

Fusobacterium - shape and gram? Where colonize?

Back 16

Fusiform (fused ends)
gram negative

Oral, vagina, colon

Front 17

Porphyromonas - shape and gram? what pigment? Where colonize?

Back 17

Gram negative rod

Black pigment

Oral

Front 18

Prevotella - shape and gram? what pigment? where colonize?

Back 18

Gram negative rod or cocci

Black pigment

Oral, vaginal flora. Brain, lung abcesses, repro abcesses

Front 19

Actinomyces - shape and gram? Where colonize?
Granules?

Back 19

Gram positive rod with branches

Oral and vaginal flora (IUD infection)

Yellow sulfur granules

Front 20

Propionibacterium - shape and gram? Where colonize?

Back 20

Gram positive rod

Skin (acne and bite wounds), GI tract

Front 21

Peptostreptococcus - shape and gram? Where colonize?

Back 21

Gram positive rod

Oral and colon (think PEPTO BISMOL - colon issues...)

Front 22

Characteristics of endogenous anaerobic infections?

Back 22

1. Proximity to colonized mucosa
2. Tissue necrosis/abcesses from trauma or injury
3. Foul smelling discharge
4. Mixed infections w/ faculatatives
5. Presence of gas in infected tissue
6. Can grow in anaerobic culture

Front 23

Can endogenous anaerobic infections respond to Aminoglycosides? Clindamycin? Metrondazole?

Back 23

DOES NOT respond to AmiNOglycosides

DOES respond to Clindamycin and Metronidazole

Front 24

What causes the foul smell in anaerobe discharge? Is the smell there during acute or chronic infection?

Back 24

Fatty acids produced from metabolism

Typically present in CHRONIC infection

Front 25

Why are anaerobic infections typically present with facultatives?

Back 25

Can help each other to establish infection

Facultative bacteria can consume oxygen for anaerobe proliferation

Front 26

What causes gas in anerobe infected tissue?

Back 26

Fermentation

Front 27

When studying anaerobes, why should you do a gram stain in addition to a cell culture?

Back 27

They will often be seen in gram stain but may not be in culture b/c culture of anaerobes can be difficult.

Front 28

What is a difference that is sometimes seen in gram staining of anaerobes compared to aerobes?

Back 28

May stain faintly - pink instead of red gram negative

Front 29

What symptoms can bacteroides cause?

Back 29

Intra-abdominal, lung, brain, pelvic abcesses

Front 30

What does "complex of species" refer to?

Back 30

B. fragillis may consist of different species - more studies needed

Front 31

How do you typically get B. fragilis infections?

Back 31

Part of normal bowel flora but can cause intra-abdominal infection post surgery/trauma

Front 32

6 virulence factors of Bacteroides fragillus

Back 32

1. Polysaccharide capsule
2. Penicillin/Aminoglycoside resistant
3. WEAK endotoxic LPS
4. Aerotolerant
5. Lipase, proteases, cytolysins
6. Some strains produce enterotoxin

Front 33

What is the function of the polysaccharide capsule?

Back 33

Antiphagocytic

Promotes abscess formation

Front 34

What does B. fragilis produce that make it aerotolerant?

Back 34

SOD and catalase

Front 35

What does the B. fragilis toxin cause? What part of the genome codes for the toxin?

Back 35

Diarrhea

Pathogenicity island

Front 36

Two endogenous anaerobes that produce black pigment?

Back 36

Porphyromonas

Prevotella

Front 37

What anaerobes cause periodontitis?

Back 37

Prevotella and Porphyromonas

Front 38

How does Fusobacterium's LPS compares to Bacteriodes'?

Back 38

Fusobacterium has NORMAL LPS - can cause septic shock and vascular collapse

Bacteriodes has WEAK LPS - won't cause septic shock

Front 39

What can Fusobacterium cause in the mouth?

Back 39

ANUG --> trenchmouth

Front 40

Clostridium - gram? Does it form spores?

Back 40

Gram +

Forms spores

Front 41

Where is Clostridium found?

Back 41

Soil --> enters through wounds and through food

Front 42

Is Clostridium part of our normal flora?

Back 42

YES

Front 43

Does clostridium produce endotoxin or exotoxin?

Back 43

Produces exotoxin

Front 44

What Clostridium causes tetanus?

Back 44

C. tetani

Front 45

What Clostridium causes gas gangrene?

Back 45

C. perfringens


(engines use gas)

Front 46

What Clostridium causes botulism?

Back 46

C. botulinum

Front 47

What Clostridium causes pseudomembranous colitis?

Back 47

C. difficile?

Front 48

What does C tetani look when stained?

Back 48

Tennis rackets (due to spores)

Front 49

What does C. tetani look on blood agar?

Back 49

Frosted appearance

Front 50

Sequence of events in pathogenesis of Clostridium tetani?

Back 50

1. Enter wound
2. Incubation period of 4 days to weeks to germinate and proliferate

Front 51

What are one way Clostridiium tetani can enter? What kind of tissue does it proliferate well in?

Back 51

Through splinters

Necrotic tissue

Front 52

Does Clostridium tetani produce local effects?

Back 52

nope

Front 53

What is the toxin C. tetani produces? What are its effects?

Back 53

Tetanospasmin (makes you spazzy)

Neurotoxic effects --> continuous contraction of voluntary muscles

Front 54

Two clinical signs of C. tetani infection?

Back 54

Clenched jaw

Arching of back

Front 55

Mechanism of tetanospasmin?

Back 55

Attacks inhibitory NT so that they cannot be relased --> get convulsive contraction of voluntary muscles

Starts at peripheral nerves and spreads to spinal cord

Front 56

Are the effects of tetanospasmin permanent?

Back 56

Yes

Front 57

How do you treat tetanospasmin infection?

Back 57

Antitoxin - human tetanus immune globulin (HTIG) - binds unbound toxin

Only way to correct damage is to grow new neurons

Front 58

Is there a vaccine for tetanospasmin?

Back 58

YES DTaP (diptheria, pertussis, tetanus)

Front 59

What precaution for tetanospasmin should you take with wound patients

Back 59

Make sure vaccines are up to date - within 10 years

Front 60

Two ways you can get infected with Clostridium botulinum toxin?

Back 60

1. Consumption of toxin--> food poisoning

2. Spores enter wound and produce toxin

Front 61

Why shouldn't babies eat honey?

Back 61

Their GI flora haven't fully developed yet

C. botulinum spores reside in honey --> can germinate inside GI tract and infect baby

Front 62

Why should you take precaution when making home-canned food?

Back 62

C. botulinum spores is often found there

They can resist boiling --> release its very potent toxin

Front 63

What is the pathogenesis of Botulinum toxin

Back 63

Highly potent neurotoxin that blocks release of acetylcholine (activator of motor neurons)

Front 64

What symptoms do you get from Botulinum toxin

Back 64

Flaccid paralysis (blurred vision, double vision, drooping eyelids, slurred speech --> paralysis)

Respiratory failure

Front 65

What causes floppy baby syndrome? What are the symptoms?

Back 65

Botulism infection of infants

Lethargic, poor feeding, weak cry, constipation decreased movements, poor muscle tone

Front 66

What patients should not be given the antitoxin for Botulinum toxin?

Back 66

Infants

They usually recover spontaneously

Front 67

Is the botulinum toxin heat stable or heat labile?

Back 67

Heat labile

Front 68

What is the pathogenesis of Clostridium perfringens?

Back 68

Gas gangrene (wound and soft tissue infections)
- gas is from fermentation
- 12 necrotizing toxins
- septic shock

Front 69

How do you treat gas gangrene?

Back 69

Remove necrotic tissue then antibiotics

Front 70

What else can C. perfringens cause other than gas gangrene?

Back 70

Food posioning due to enterotoxin

Found in rich meat dishes that are kept warm --> allows spores to germinate

Front 71

Clostridium difficile can produce diarrhea in patients on what antibiotic?

Back 71

Fluroquinolones

Front 72

What are the toxins that C. difficile produce? What symptoms do they cause?

Back 72

"A" enterotoxin --> disruption of cellular junctions --> watery diarrhea

"B" cytotoxin --> tissue necrosis --> pseudomambranous plaques

Front 73

What other symptoms can C. difficile produce?

Back 73

Toxic megacolon and abdominal distension (due to gas production)

Front 74

What type of patients are susceptible to recurrent C. difficile infections?

Back 74

65+ age

Immunocompromised

Spores are also common in healthcare envirnments

Front 75

What are pseudomembranous plaques in C.difficile infections composed of?

Back 75

Inflammatory debri on mucosal surface