anaerobic infections and normal flora Flashcards Preview

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Flashcards in anaerobic infections and normal flora Deck (42)
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1
Q

noticeable characteristics of most anaerobic infections:

A
  • abscesses - from native flora
  • foul-smelling discharge
  • gas in necrotic tissue
2
Q

where do most anaerobic infections occur?

A

deep or necrotic tissue where the oxygen is low ( lack of oxidation-reduction potential) and access to endogenous local bacteria is available

3
Q

predisposing conditions for anaerobic infections:

A
  • pulmonary aspiration
  • bowel surgery
  • poor dental hygiene
  • abortion
  • human or animal bites
  • trauma
  • malignancy
4
Q

do most anaerobic infections involve only one organism?

A
  • no, in contrast to aerobic infections, most anaerobic infections involve multiple offending organisms
5
Q

diaphragm and bacteroides fragilis

A

bacteroides fragilis is penicillin resistant and is only found in infections below the diaphragm (distinguishes upper from lower GI tract infection)

6
Q

common anaerobes in dental infections

A
  • prevotella
  • fusobacterium nucleatum
  • peptostreptococcus
  • actinomyces
7
Q

common anaerobes in CNS infections

A

oral anaerobes

8
Q

common anaerobes in otitis media

A

oral anaerobes

9
Q

common anaerobes in lung infections

A
  • prevotella
  • fusobacterium
  • peptostreptococcus
10
Q

common anaerobes in peritonitis

A
  • bacteroides fragilis
  • fusobacterium
  • peptostreptococcus
  • clostridium
11
Q

common anaerobes in liver and subphrenic abscesses

A

colonic flora

12
Q

common anaerobes in OB/GYN infections

A

colonic flora

13
Q

common anaerobes in perirectal abscesses

A

colonic flora

14
Q

common anaerobes in skin and muscle infections

A

clostridium

15
Q

bacteroides fragilis shape and gram stain

A

gram negative rod

16
Q

which two anaerobes combined cause about 80% of all anaerobic septicemias and about 8% of all septicemias?

A

bacteroides fragilis and clostridium perfringens

17
Q

where is bacteroides fragilis found

A

large numbers in large intestine

18
Q

what is the most important characteristic of bactericides fragilis?

A

penicillin resistant

19
Q

is prevotella sensitive to penicillin?

A

yes, many strains are

20
Q

which is more sensitive to oxygen when trying to culture? bacteroides fragilis or prevotella?

A

prevotella

21
Q

shape and gram stain of prevotella

A

gram negative rod

22
Q

shape and gram stain of fusobacterium

A

gram negative rod - but very thin and needle shaped

23
Q

is fusobacterium senstive to oxygen? penicillin?

A

yes to both

24
Q

most common bacteroides infections

A

intraabdominal, female genital

25
Q

most common prevotella infections

A

peridontal, sometimes genital

26
Q

most common fusobacterium infections

A

oral infections, lung abscesses, abdominal

27
Q

name 3 anaerobic gram negative rods

A
  • bacteroides fragilis
  • prevotella melaninogenicus
  • fusobacterium
28
Q

what are the spore forming anaerobic gram positive rods?

A

clostridium species

29
Q

4 non-spore forming anaerobic gram positive rods

A
  • bifidobacterium
  • corynebacterium
  • lactobacillus
  • actinomyces
30
Q

corynebacterium infections

A
  • endocarditis in compromised patients
31
Q

where is corynebacterium usually found?

A

normal inhabitant of skin

32
Q

where is lactobacillus found?

A

normally in intestine and vagina

33
Q

lactobacillus is important for:

A

maintaining low pH

34
Q

actinomyces normally found in

A

oral pharynx, GI tract

35
Q

what feature is characteristic of actinomyces infections?

A

sulfur granules, yellow granules seen in lesions that are composed of micro colonies

36
Q

name 2 anaerobic gram positive cocci

A
  • peptostreptococcus

- peptococcus

37
Q

peptostreptococcus normally found in:

A

mouth, urogenital and GI tract

38
Q

peptococcus normally found in:

A

mouth, upper resp tract, large intestine

39
Q

name an anaerobic gram negative cocci

A

veillonella

40
Q

what antibiotics are effective against bacteroides fragilis?

A

newer cephalosporins such as cefoxitin

41
Q

what is the proper treatment for mixed aerobe-anaerobe infections? (very common)

A

aminoglycoside + antibiotic for anaerobes

like: gentamicin + cefoxitin or gentamicin + clindamycin

42
Q

is penicillin effective against anaerobes?

A

yes, except for bacteroides fragilis, therefore penicillin alone is not used for infections below the diaphragm