Upper GI Micro

Question 1

predominant anaerobes in GI tract

Answer 1

bacteroidetes and firmicutes

Question 2

_____ is required for abscesses

Answer 2

both anaerobes and aerobes

Question 3

contrast supraginigival plaque-associated biofilm (PAB) and subgingival

Answer 3

supra: aerobic or aerotolerant G+ (actinomycetes)
sbu: G-anaerobes (bacteroides)

Question 4

describe bacteroides

Answer 4

G-
non spore
anaerobic

Question 5

location of bacteroides

Answer 5

oropharynx, intestines, female genital tract

Question 6

bacteroides benefits (4)

Answer 6

• fermentation of complex carbs
• acquisition of N
• recycling bile acids
• colonization resistance

Question 7

most common genus from anaerobic infections

Answer 7

bacteroides

Question 8

bacteroides infection requires ________

Answer 8

breach of epithelial barrier (they are unable to invade cells)

Question 9

describe actinomyces

Answer 9

G+, non spore, anaerobic

have hyphae like structures

Question 10

risks for actinomycosis

Answer 10

poor oral hygiene, smoking, heavy alcohol

usually following dental procedures in adults

Question 11

describe actinomyces infection

Answer 11

aka lumpy jaw

chronic infection- takes 4-6 wks penicillin and yr of antibiotics

possible drainage and sulfur granules

Question 12

describe clostridium

Answer 12

in firmicutes phylum

G+, spore forming

everywhere in environment, some are anaerobes (C diff) and some are tolerant

Question 13

clostridium fermentation

Answer 13

can ferment carbs, fatty acids, AAs

products have foul odor

Question 14

diseases from 4 clostridial pathogens

Answer 14

perfringens- gas gangrene

septicum- gas gangrene, can spread via blood since aerotoleran

botulinum- food poisoning and wound botulism

difficile- antibiotic resistant diarrhea and colitis

Question 15

contrast tetani and botulinum toxins

Answer 15

T- prevents inhibitory neurotransmitters, causes spasticity

B- prevents stim, causes paralysis

both binary AB toxins, binding and active proteins w/ S-S bond

Question 16

C perfringens toxin

Answer 16

alpha toxin, lecithinase degrades tissue

Question 17

C diff toxin

Answer 17

toxin B, single protein, cytotoxic and inflammatory

Question 18

contrast gas gangrene from septicum and perfringens

Answer 18

septicum- more spontaneous, clostridial myonecrosis can have mortality up to 100%

perfringens- from trauma

Question 19

Dx of anaerobic infection

Answer 19

use abscess, tissue, blood aspirates, NOT anything touching mucus membrane

rapid transport

Question 20

always active and never active drugs against anaerobes

Answer 20

always: MCB
metronidazole
carbapenems
B lactams/clauvanate

never: ATA
aminoglycosides
Tmp-Smx
Aztreonam

Question 21

tx of esophagitis

Answer 21

often done empirically w/ fluconazole- candida is most common pathogent

Question 22

H pylori pathogenesis

Answer 22

1. need flagellar motility
2. urease converts urea to ammonia, raises pH
3. replicate
4. mucinases and effectors damage epithelium, cause inflammation

can lead to ulcers

Question 23

Cag gene impact on H pylori

Answer 23

Cag+ strains more likely to cause ulcers and gastric cancer

found of mobile pathogenicity island

Question 24

tx of H pylori ulcers

Answer 24

triple therapy:

1. amoxicillin (or metronidazole)
2. clarithromycin
3. PPI

sometimes add bismuth