GI infections 4 Flashcards
non inflammatory diarrhea usually involves the _____ intestine
small intestine; viruses and non invasive bacteria
NO mucosal destruction
_________ toxin helps in the activity of TcdA and TcdB
binary toxin (CDT aka C. difficile transferase)
what are the top 5 food borne illness pathogens
- norovirus
- salmonella
- clostridium perfringens
- campylobacter
- staph aureus
describe the biology of Clostridium difficile:
- gram POSITIVE bacillus
- anaerobic
- endospore FORMER
- primary cause of antibiotic associated diarrhea in hospital settings
use of __________ (antibiotic) is associated with a high risk factor for C. difficile infection
clindamycin (because it affects the gut microbiota the most)
___________ is useful for initial screening for C. difficile infection
EIA for glutamic dehydrogenase antigen (GDH)
________ is the primary cause of antibiotic associated diarrhea in hospital settings
clostridium difficile
C. difficile has secreted ____toxins (exo/endo) which are TcdA and TcdB which cause __________ by ________
EXOtoxins that can cause disruption of the actin cytoskeleton by inhibiting GTPase activity by transferring glucose onto GTPases involved in regulation of the cytoskeleton
describe course of clostridium difficile infection
- can be mild and be a self limiting diarrhea
- can also develop into pseduomembranous colitis
- severe cases can develop into toxic megacolon
is C. difficile a food borne illness?
no, technically it is not because it is part of the normal microbiota of the gut and get infection when you alter the gut microbiota
______ infection can regress to pseudomembranous colitis
clostridium difficile
describe the biology of bacteroides fragilis
- GNAR: gram negative anaerobic, NON SPORE forming rod
- part of the normal flora of the large intestine
- mostly associated with opportunistic infections
what are some risk factors that increase the chance of acquiring a C. difficile infection?
- antibiotic use: ↑ with days and number
- type of antibiotic use: clindamycin has the highest risk and ahminoglycosides have the lowest
- patient age: older than 65 higher risk
- history of hospitalization and length of stay
__________ is a very common cause of intrabdominal abscesses
bacteroides fragilis
a doctor orders a glutamate dehydrogenase antigen assay for a patient who has had water diarrhea for the past 4 days. What pathogen is he screening for?
C. difficile
in what settings do you seen clostridium difficile infection?
- hospital settings
- after exposure to antibiotics which alter the gut microbiota
routine stool culture is for : (4)
- campylobacter
- salmonella
- shigella
- E. coli (all types)
describe the oxygen demands for clostridium difficile
obligate anaerobes
inflammatory (blood-pus, fever) diarrhea usually invites the _________ intestine
large intestine; invasive bacteria and toxin producing bacteria
what are some virulence factors of bacteroides fragilis?
- fimbrae for adhesion
- polysaccharide capsule: evasion of host response and triggers abscess formation
- β lactamases
- NO CONTRIBUTION OF LPS
_______ is the form of Clostridium difficile that you seen on fomites such as health care workers hands and the environment
endospores
spore forming GI microbes (2)
bacillus and clostridia
which specific pathogens have incubation period more than 7 days to weeks/months?
- listeria monocytogenes
- parasites (will do an ova and parasite stool investigation)
- liver infections such as Hep A which is a food borne hepatitis
