GI Acute Inflammatory Diarrhea Flashcards
the endotoxin of Shigella spp. is the _____
the endotoxin of Shigella spp. is the O antigen
the exotoxin of Shigella spp. is ____
the exotoxin of Shigella spp. is enterotoxin that acts as neurotoxin (causes meningismus, coma, ulceration)
all Shigella spp. produce NAD glycohydrolase which ____
all Shigella spp. produce NAD glycohydrolase which destroys all NAD in human cells, shuts down metabolism and leads to cell death
the mildest form of Shigella infection is caused by ____ and leads to watery type of diarrhea with vomiting, abdominal pain and dehydration
the mildest form of Shigella infection is caused by S. sonnei and leads to watery type of diarrhea with vomiting, abdominal pain and dehydration
describe the pathogenesis of Shigella spp.
- ingestion of bacteria
- attachment to LI epithelia (M cells of Peyer’s patches)
- invasion (plasmid induced endocytosis)
- lysis of phagosome
- replicate within cytoplasm
- move from host cell to host cells with aid of actin filament
- induce cell apoptosis → release of ILs
Shigella spp. attaches to the ___ epithelia (___ cells of ___)
Shigella spp. attaches to the LI epithelia (M cells of Peyer’s patches)
Shigella spp. move from host cell to host cells with aid of ____
Shigella spp. move from host cell to host cells with aid of actin filaments
Shigella spp. induce ____ which leads to the release of ___
Shigella spp. induce apoptosis which leads to the release of interleukins
Shigella dysenteriae produces ____ (cytotoxin) which _____
Shigella dysenteriae produces Shigella toxin (cytotoxin) which inhibits protein synthesis (inactivates 28s RNA in 60S ribosomal subunit)
Shiga toxin also acts as:
enterotoxin because ____
exotoxin because ____
neurotoxin because _____
Shiga toxin also acts as:
enterotoxin because it produces diarrhea
exotoxin because it inhibits sugar and AA absorption in SI
neurotoxin because affects CNS
Shigella sonnei commonly affects ____
Shigella sonnei commonly affects children <5 years (day care)
Shigella flexneri commonly affects ____
Shigella flexneri commonly affects men who have sex with men
describe diagnosis and identification of Shigella spp.
- isolation from stools, water and food
- MacConkey agar
- pale/colorless colonies
- S-S agar (Salmonella-Shigella agar)
describe characteristics of Shigella toxin
- non-motile
- G-ve rod
- NO fermentation of lactose
- NO utilization of citric acid
- NO H2S prodxn
- NO gas from glucose
describe the Sketchy
the difference between Enteroinvasive E. coli (EIEC) and Shigella is that EIEC does NOT make ____
the difference between Enteroinvasive E. coli (EIEC) and Shigella is that EIEC does NOT make Shiga toxin
EIEC is commonly found in ____
EIEC is commonly found in SE Asia/S. America
describe the pathogenesis of EIEC
- ingestion
- invasion of LI
- lysis of phagosome
- replicate in cytoplasm
- spread from host cell to host cell
- destroy colonic cells
list the complications of Salmonellosis
cardiovascular, CNS, pulmonary, reactive arthritis, osteomyelitis, hepatobiliary
describe enterocolitis (gastroenteritis) caused by Salmonella
localized infection, excessive fluid secretion from ileum & jejunum
name the 3 organisms that cause gastroenteritis
S. typhimurium, S.* *enteritidis, S. newport
describe the diagnosis of enterocolitis, septicemias and enteric fever caused by Salmonella
stool cultures from a patient with enterocolitis (caused by Salmonella) would show _____
stool cultures from a patient with enterocolitis (caused by Salmonella) would show +ve soon after onset
stool cultures from a patient with septicemias (caused by Salmonella) would show _____
stool cultures from a patient with septicemias (caused by Salmonella) would show infrequently +ve
stool cultures from a patient with enteric fever (caused by Salmonella) would show _____
stool cultures from a patient with enteric fever (caused by Salmonella) would show +ve from 2nd week on; -ve early
describe the pathogenesis of Salmonella
- ingestion of bacteria
- attachment to SI epithelia (PAI encoded)
- invade M cells of Peyer’s patches + enterocytes (PAI encoded)
- replicate within vacuole (PAI encoded)
- transported across cytoplasm
- released into blood/lymph
Salmonellosis is commonly associated with handling ____
Salmonellosis is commonly associated with handling reptiles (lizards, snakes, turtles, frogs)
in the US, cases of enteric fever are seen only in travelers to ___, ___ and ____
in the US, cases of enteric fever are seen only in travelers to Asia, Mexico and India
describe the pathogenesis of enteric fever
- in bloodstream
- macrophage engulfment
- transported to liver, spleen and bone marrow
- colonization of gallbladder
- replicate in bile
- re-enter intestines
describe the diagnosis of enteric fever
- history of travel to endemic areas
- transient, macular rash (rose-colored) on trunk
- examination of blood
- anemia, leukopenia, absence of eosinophils
- blood culture for isolation of S. typhi
- multiple samples to increase sensitivity
describe the isolation and identification of Salmonella
- isolation from stools, water and food
- MacConkey agar plate
- pale/colorless
- S-S agar (Salmonella-Shigella agar)
list characteristics of Salmonella
- motile
- G-ve rod
- NO fermentation of lactose
- H2S production
- gas from glucose
- serotyping
describe the Sketchy
