Bacterial and Viral GI Infections (Quiz 2) Flashcards
what feature of GI bacteria allows them to live in the stomach and survive stomach acid
- those without envelopes (have sturdy capsids)
- secretion of enzymes to buffer pH (H. pylori & urease)
- inherent acid resistance (Shigella spp.)
how does bacterial overgrowth syndrome occur
symptoms it can cause
- decrease amount of acidity in the stomach
- increase number of microbes
- grow further into the stomach/small intestine
- vitamin deficiencies
- fat malabsorption
- malnutrition
which classification of enteric bacterial pathogens is caused by facultative intracellular pathogens and relies on invasion of host cells
examples and gram stain
- enteroinvasive
- Salmonella enterica (gram -)
- Shigella (gram -)
- Yersinia enterocolitica
- Campylobacter jejuni (gram -)
- Listeria monocytogenes (gram +)
- Enteroinvasive E. coli
ENTEROINVASIVE BACTERIA ARE CLESSY
which classification of enteric bacterial pathogens is caused by bacteria that produce enterotoxin and invasion does NOT play a role in disease
examples and gram stain
- Enterotoxic
- Vibrio cholerae (gram -)
- ETEC
- C. diff
VEC
which classification of enteric bacterial pathogens is caused by bacteria that destroy epithelium and invasion does NOT play a role in disease
example and gram stain
- Enteropathogenic
- EPEC (gram -)
- EHEC (gram -)
- H. pylori
HEE!
which classification of enteric bacterial pathogens does invasion play a role in disease
- Enteroinvasive
rice water stool associated with which bugs
- V. cholerae, ETEC
they secrete bacterial toxins
Typhoid group of Salmonella enterica affects what species
what about nontyphoid salmonella enterica
- humans only
- animals and humans
Salmonella enterica serovar typhi is a _________ pathogen
states of typhoid fever
where does it colonize?
describe its infection
- obligate human
- carrier state with shedding of bacteria
- biliary duct
- starts out as GI infection and disseminates to other organs in a systemic infection
infectious dose of S. enterica typhoid variant
what about non-typhoid
- low
- high
are antibiotics recommended as treatment for S. enterica typhi
which ones?
what about non-typhoid variants
- yes
- Ciprofloxacin or Ceftriaxone
- no
where does Shigella colonize
how?
motility patterns of Shigella spp
any animal reservoirs?
how is it transmitted
treatment
- lower intestine of humans
- acid resistant
- nonmotile
- no animal reservoirs
- person-person
- rehydration +/- Antbiotics
where would you find:
S. sonnei
S. flexneri
S. dysenteriae
- US and developed world
- developing world
- epidemics
why do we generally not give people with shigellosis antibiotics
which antibiotic
- can cause hemolytic uremic syndrome
- ciprofloxacin
Shiga toxin of S. dysenteriae and EHEC
where is its G3b receptor expressed
- A+B toxin
- blocks absorption of glucose, electrolytes, and amino acids
- associated with development of HUS
- endothelial cells of intestine, kidney, and brain
C. jejuni requires what kind of agar to grow
- charcoal
what is the most common bacterial cause of diarrheal disease in the US
shape
what is its infectious dose
treatment
- Campylobacter
- cork-screw rod
- low infectious dose
- rehydration
which bacteria grows at refrigerator temp
hosts
treatment for invasive infections
- Listeria monocytogenes
- range of hosts, humans, birds, fish
- IV antibiotics (ampicillin and gentamicin) for 14-21 days
motility pattern of L. monocytogenes
- actin-based
- propels from one cell to another using host actin so it doesn’t have to enter extracellular environment
how Listeria is spread
common objects?
- foodborne
- mother-child
- dairy
- processed meats
what population do we worry about with listeria
why
- pregnant women
- they may have mild flu-like symptoms but can cause series defects for their baby like miscarriages, stillbirth, and pre-term labor
- can also cause CNS infection in neonates
where do you normally find Vibrio in the environment
any infected animal hosts?
important shape of vibrio
transmission by
- fresh, brackish or marine water
- on shells of crustaceans
- no (humans only)
- comma-shaped rod
- contaminated water or food
how do cholera toxin and ETEC labile toxin work
- A+B toxin
- activates adenylate cyclase which results in secretion of electrolytes and water resulting in profuse, watery diarrhea
what do Enterotoxigenic E. coli do
- deliver enterotoxin
