45 Anaerobes I Flashcards Preview

HDID 2 > 45 Anaerobes I > Flashcards

Flashcards in 45 Anaerobes I Deck (32):
1

anaerobes fail to grow on the surface of what?

solid media in air (18% O2) supplemented w/5-10% CO2

moderate anaerobe: 2-8% O2 (eg propionibacterium, clostridium)

strict anaerobe:

2

probiotics containing anaerobes (eg _____ & _______) are ingested by many people to maintain indigenous anaerobe flora.

lactobacilli, bifidobacteria

3

majority of anaerobic infections are endogenous or exogenous?

endogenous, but most exogenous infections are caused by clostridia

4

what is the disease assoc w/each?:
C.tetani
C.botulinum
C.perfringens
C.difficile

C.tetani - tetanus

C.botulinum - botulism

C.perfringens - food poisoning, cellulitis, myositis, myonecrosis

C.difficile - diarrhea, pseudomembraneous colitis

5

body parts w/highest [Anaerobes]?

teeth, gingiba, colon, vagina (not stomach because of acidic pH)

6

which anaerobic bacteria is the outlier that colonizes the skin?

propironibacterium

7

infection w/a facultative anaerobe does what to anaerobes?

uses up the already diminished O2 supply and thus encouraces growth of obligate anaerobes

8

clinical and lab clues for anaerobic infections?

- foul odor from lesion or discharge

- infection near mucosal surface

- tissue necrosis, gangrene, abscess formation w/gas

- assoc w/malignancy

- diarrhea assoc w/Abx tx

- massive hemolysis

- sulfur granules in discharge

- unique gram stain morphology

- fail to grow aerobically

9

problems w/identification of anaerobic infections?

- derived from normal flora - is it a pathogen or contaminant? Tell by clinical sxs

- death by air

- slow growth of orgs (due to inefficiency of fermentation)

10

appropriate specimens for anaerobic cx?

- collected in a sterile manner
- tissue biopsies, surgical specimens, needle aspirates, blood

NOT: contaminated w/orgs colonizing the skin and mucosal surfaces like swabs, sputum, or urines

11

anaerobic, non-spore forming GP rods?

actinomyces, lactobacillus, mobiluncus, propionibacterium

12

anaerobic GP cocci?

peptostreptococcus

13

peptostreptococcus disease?

Polymicrobial infections:
- Sinusitis, pleuropulm infecteions, brain abscesses
- intraabd. Infections
- endometritis, pelvic abscesses
- cellulitis, necrotizing fasciitis
- osteomyelitis

14

peptostreptococcus treatment?

- usu susceptible to penicillin but tx should cover all orgs of infection – generally combination therapy: beta-lactam-beta-lactamase inhibitor, can include metronidazole combined w/extended spectrum cephalosporin, aminoglycoside, or FQ
- empiric therapy adjusted when results of susceptibility tests available

15

actinomyces general characteristics?

- delicate filamentous structure

-sulfur granules colony

16

actinomyces pathogenesis?

- chronic lesions that become suppurative and form abscesses connected by sinus tracts
- involves disruption of mucosal barrier (surgery like dental procedures/GI surgery, trauma, aspiration, foreign body like IUD, diverticulitis, appendicitis)

17

actinomyces disease?

Actinomycosis
- cerebral
- cervicofacial
- thoracic
- abdominal
- pelvic

Chronic infection w/relapsing/remitting course assoc w/abscess, draining sinuses, fibrosis

- often mistaken for malignancy

18

actinomyces treatment?

Abx: penicicllin; erythromycin or clindamycin

Surgical debridement (liver is highly vascular, thus [Abx] is high enough and don’t need debridement)

19

lactobacillus general characteristics?

long, thin GP rods (non-spore-forming)

mostly clinically insignificant (found in probiotics)

20

lactobacillus disease?

may cause septicemia in immunocompromised or endocarditis in ppl w/underlying valve abnormalities

- bloodstream infection of lactobacillus causing endocarditis

21

lactobacillus treatment?

Abx: high [penicillin] and gentamicin (pcn or a combo of Abx) – bacteria resistant to vancomycin

22

mobiluncus general characteristics?

curved rod, GN or G-variable

colonizes genital tract

23

mobiluncus disease? dx? tx?

- multiplies to high numbers in women w/ bacterial vaginosis (may be impt cause or marker of disease)

- clue cells suggest Dx of BV

- tx of BV w/metronidazole (even though Mobiluncus itself is resistant)

24

propionibacterium general characteristics?

clumps of short rods
- most commonly isolated anaerobe in microbiology lab

25

propionibacterium disease and treatment?

- acne
- invasive infections in pts w/indwelling foreign bodies: prosthetic heart valves, prosthetic joints, indwelling catheters

- topical benzoyl peroxide
- penicillin, tetracyclines, erythromycin, clindamycin

26

bacteroides fragillis general characteristics?

anaerobic GN rod w/LPS but lacks endotoxin activity

most common clinically significant anaerobe

grows easily in culture (pleimorphic GNRs w/inflammatory cells)

27

B.fragilis virulence?

polysaccharide capsule prevents phagocytosis and stimulates abscess formation

other factors too

28

B.fragilis disease? dx? treatment?

abscess formation:
- intraabdominal infections
- PID and endometritis
- surgical wound infections
- S/ST infections after surgery or trauma

dx: grows well in culture, always consider post-op (tends to be necrotic and thus crepitus present)

tx: - resistant to penicillins
- metronidazole plus active vs other organisms in infection (polymicrobial)
- surgical debridement

29

fusobacterium general characteristics?

anaerobic GNR

- normal flora of oropharynx, GI and GU, long, filamentous

30

fusobacterium pathogenesis?

- untreated dental caries extend to dental alveoli and result in osteomyelitis or may spread into mandible
- spreads to thorax via parapharyngeal spaces

31

fusobacterium disease?

- acute necrotizing ulcerative gingivitis (“trench mouth”)
- pharyngitis, tonsillitis (Vincent’s angina)
- Jugular venous thrombophlebitis (Lemierre’s syndrome) = pharyngitis complicated by peritonsillar abscess w/subsequent spread through pharyngeal spaces inferiorly  into internal jugular  localized thrombophlebitis  clots embolize to other organs (**lung) and form abscesses at those sites

32

fusobacterium treatment?

- penicillin and clindamycin

For Lemierre’s: B-lactam-B-lactamase inhibitor and debridement of abscess