Unit 9: Anaerobes Flashcards

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1
Q

What are the two primary groups of anaerobic GPCs?

A

Peptostreptococcus

Anaerococcus

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2
Q

What do P. anaerobius and B. dentium have in common and how would you differentiate them?

A

Both indole and Nitrate reduction NEG

P. anaerobius is SPS disc SS

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3
Q

What is the 2nd most common group of anaerobes ?

A

GPCs

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4
Q

How would you treat P. anaerobius?

A

Treated with penicillin G and cephalosporins

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5
Q

Habitat of Veillonella?

A

-Normal flora of mouth and gut

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6
Q

What would you do if the Vancomycin disk is sensitive but you had a gram stain with GNC?

A

Redo gram stain, you probably overdecolorized

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7
Q

What is a common cause of blood culture contamination?

A

Propionibacterium acnes

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8
Q

Propionibacterium acnes: habitat

A

-Normal skin flora

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9
Q

What result would give a presumptive ID of Propionibacterium acnes?

A

A GPB that is Indole POS

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10
Q

Why would you perform a Nitrate test on presumptive P. acnes?

A

To rule out C. diff. P. acnes is POS

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11
Q

Eubacterium lentum: habitat

A

Normal flora of intestinal tract

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12
Q

What are significant test results for Eubacterium lentum? What does it need to be differentiated from and how?

A
  • POS catalase so Differentiate from Propionibacterium w/ gram stain; E. lentum=small GPB and P. acnes is pleiomorphic
  • Colistin R
  • Very little biochemical activity
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13
Q

What genus produces sulfur granules?

A

Actinomyces

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14
Q

What is the main issue caused by Actinomyces species in general?

A

problems with IUDs

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15
Q

Actinomyces israelii: habitat

A

Normal flora of mouth

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16
Q

Are Actinomyces species generally Nitrate production pos or neg?

A

POS

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17
Q

Which Actinomyces is Nitrate NEG?

A

A. meyeri

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18
Q

How would you differentiate A. Israelii and A. naeslundii? And why is it necessary?

A

Both are Nitrate POS Actinomyces species and A. Israelii is always able to hydrolyze esculin while A. naeslundii is variable.

A.naeslundii is urease POS

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19
Q

How would you differentiate A. vicosus and A. naeslundii? And why is it necessary?

A

Both are Nitrate POS Actinomyces species that are urease POS

A. vicosus is catalase POS

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20
Q

A nitrate POS and catalase NEG anaerobic GPB: What are the possibilities and how to you differentiate?

A

A. israelii- can hydrolyze esculin
A.naeslundii-Urease POS
A.odontolyticus-neither

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21
Q

What is the only Actinomyces that is catalase POS?

A

A. vicosus

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22
Q

A nitrate POS and catalase POS anaerobic GPB: What are the possibilities and how to you differentiate?

A

P.acnes- pleomorphic
E. lentum- small GPB
A. vicosus- Urease POS

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23
Q

What are the 5 Actinomyces species we care about?

A
A. israelii
A.naeslundii
A.odontolyticus
A.vicosus
A. meyeri
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24
Q

A nitrate NEG and catalase NEG anaerobic GPB: What are the possibilities and how to you differentiate?

A

A. meyeri

B. dentium- Can hydrolyze esculin

25
Q

B. dentium: habitat

A

normal flora of mouth, GI and stool

26
Q

anaerobic GPB: -Aerotolerant and Microaerophilic

A

A.odontolyticus
B. dentium
Lactobacillus spp

27
Q

anaerobic GPB: Aerotolerant NOT Microaerophilic

A

A.vicosus

A.naeslundii

28
Q

How can you presumptively ID Lactobacillus?

A

GPB in chains

Catalase NEG

29
Q

What is special about catalase used for anaerobes?

A

It is 15% instead of 3%

30
Q

How can you ID Bacteroides fragilis group?

A
  • Anaerobic GNB
  • Resistent to bile, colistin, vancomycin AND kanamycin
  • Hydrolyzed esculin
31
Q

Name and differentiate the species of the Bacteroides fragilis group

A
Indole POS, catalase POS= 
  -B. ovatus
  -B. thetaiotaomicron
Indole NEG, catalase NEG=
  -B. vulgatus 
Indole POS, catalase NEG=
  -B. uniformis
Indole NEG, catalase POS
  -B. fragilis
  -B. distasonis
32
Q

How would you presumptively ID Prevotella and Porphyromonas and what you you report?

A
  • Brick red under UV light after at east 3 days

- Pigmented Porphyromonas

33
Q

What differentiates Prevotella and Porphyromonas?

A

Porphyromonas is asaccharolytic- but difficult to determine which is which

34
Q

Which GNB pits the agar?

A

Bacteroides urealyticus

35
Q

What is the only anaerobic GNB that can grow in 20% bile? Plus another 2

A

B. fragilis group

also F. mortiferum and F. varium

36
Q

Which anaerobic GNB is nitrate POS and urease POS?

A

B. urealyticus

37
Q

Which two vancomycin (only) resistant GNBs are indole POS and how do you differentiate them?

A

F. nucleatum

F.necrophorum- Lipase POS, causes greening of agar

38
Q

What do all the Fusobacterium species have in common?

A

All are vancomycin resistant ONLY

39
Q

Which is associated with ulcerative colitis?

A

F. varium

40
Q

Which two Fusobacterium species can hydrolyze esculin?

A

F. mortiferum

F. varium

41
Q

What does C.perfringens cause?

A
  • Food poisoning (endotoxin)
  • Self limiting

-Gas gangrene (rapid invasion and necrosis)

42
Q

Clostridium species: habitat

A
  • Widespread in nature
  • Normal flora in GI tract: humans and animals
  • Specifically: female genital tract and oral mucosa
43
Q

How can you tell a GPB with spores is C.perfringens?

A
  • Double zone of Beta hemolysis
  • resistant to colistin
  • Lecithinase, reverse CAMP and Nagler test POS
44
Q

How can you tell a GPB with spores is C.septicum?

A
  • Hydrolyzes esculin

- Medusa head like colony/swarms

45
Q

What does C, septicum cause? What is it associated with?

A
  • Septicemia

- Associated with malignancies

46
Q

What does C. difficile cause if untreated?

A

Pseudomembranous colitis

47
Q

C. difficile: two toxins

A

Toxin A-enterotoxin; produced in intestines

Toxin B-cytotoxin

48
Q

C. difficile: habitat

A

Prevalent in soil

49
Q

What does C. difficile cause (no matter what)?

A

Antibiotic associated diarrhea

50
Q

How can we identify C. difficile?

A
  • Grows on CCFA agar

- Rapid EIA

51
Q

C.botulinum: 3 types

A
  • Food borne
    • Infant botulism (Most common; breastmilk; honey)
    • Wound botulism
52
Q

Specimen types for C.botulinum (4)

A
  • Serum
  • Stool
  • Gastric aspirates
  • Vomit
53
Q

C.botulinum: What type of spores

A

subterminal

54
Q

How do we identify C.botulinum?

A

serological

55
Q

What toxin is associated with C. tetani? How does it work?

A

Nerotoxin-tetanospasmin - blocks inhibitory impulses of the CNS

56
Q

C. tetani: What type of spores

A

Terminal

57
Q

What clostridium is Lecithinase and lipase NEG?

A

C. tetani

58
Q

How to not confuse Bacillus spp with Aerotolerant clostridium?

A

Bacillus is Catalase POS and grows better/forms spores aerobically

59
Q

What is the better antimicrobial susceptibility testing if you can’t use commercial ID?

A

Microtube broth dilution method