Gi - Dickinson - Dysentery

Front 1

Define Dysentery

Back 1

Frequent, bloody stools typically with mucus and pus, abdominal pain, tenesmus (=feeling like you constantly need to pass stool) and fever

Front 2

Blood, mucus and pus in the stool suggests what?

Back 2

Inflammatory invasion of colonic mucosa

Front 3

What type of stool do Salmonella and Shigella cause?

Back 3

Bloody, mucus, pus stool

Front 4

Define Enterobacteriaceae

Back 4

Bacterial antigens used for IDing purposes

Front 5

How is shigella and salmonella spread?

Back 5

fecal-oral (ex. = water with feces)

Front 6

If we look at the colon of a pt. with Shigellosis (infected with Shigella) what will we see on colonoscopy?

Back 6

Luminal narrowing, mucosal inflamm, severe inflamm infiltrate of neutrophils and macrophages in underlying mucosa

Front 7

Do we need a high or Low infective dose of shigella?

Back 7

LOW b/c its resistant to stomach acid

Front 8

What type of shigella predominates in developed countries?

Back 8

Shigella sonnei

Front 9

Which Shigella forms shiga toxin?

Back 9

shigella dysenteriae

Front 10

MOA of Shiga toxin?

Back 10

Shiga toxin --> cleaves adenine residue from 28S rRNA of Large 60S euk. ribosomal subunit --> blocks protein synth --> colonocytes die by apoptosis

Front 11

MOA of shigella invasion

Back 11

M cell is how shiga toxin enters

Front 12

What limits the spread of shiga toxin as it enters an M cell to invade epithelium?

Back 12

Neutrophils are recruited by cytokines IL-8 and IL-18 which are released by the macrophage that resides in the pocket of the M cell that shiga toxin invades

Front 13

How do surface erosion or ulcers occur with shiga toxin invasion?

Back 13

Shiga toxin invades M cell --> macrophages produce IL-8 and IL-18 --> These cytokines recruit neutrophils to clear infection --> shiga toxin doesn't spread --> cells shiga HAS invaded die and slough off = ulcer

Front 14

What feature of M cells make them easy targets for Shiga toxin?

Back 14

M cells have minimal brush border

Front 15

What three things do we use to Dx Shigella and Salmonella?

Back 15

TSI
MacConkey agar
Hektoen agar

Front 16

Shigella is a gram what organism?

Back 16

Gram Neg Bacillus

Front 17

How is Salmonella spread?

Back 17

fecal-oral

Front 18

What are the two presentations of Salmonella?

Back 18

Gastroenteritis and typhoid (enteric) fever

Typhoid fever = caused by salmonella typhi and paratyphi

Front 19

Where are the O antigens of Salmonella?

Back 19

LPS

Front 20

Where are the H antigens of Salmonella?

Back 20

Flagella

Front 21

Whats is te virulence feature of Salmonella that interferes with phagocytosis?

Back 21

Vi capsule interferes with phagocytosis

Front 22

How is salmonella obtained in the body?

Back 22

ingested with food with fecal matter on it OR through water with fecal matter in it

Front 23

What are the 5 "F"s of food-borne infection with Salmonella?

Back 23

Flies
Food
Fingers
Feces
Fomites

Front 24

Which types of salmonella cause gastroenteritis?

Back 24

Salmonella:
Choleraesuis
Enteritidis
Dublin
Typhimurium

Front 25

Which types of Salmonella cause Typhoid fever (=systemic illness, evade neutrophils = systemic spread = enter blood stream. survive and replicate in macrophages and monocytes resulting in waves of bacteremia = the symptomatic phase of the disease)

Back 25

Salmonella Typhi
Salmonella paratyphi

Front 26

Which type of Salmonella causes 70% of the infection in the US?

Back 26

Salmonella enterica serotype enteriditis

Front 27

We see exudative inflamm infiltrates in intestine that are dominated by a massive influx of neutrophils. Whats your Dx?

Back 27

Gastroenteritis prob caused by Salmonella eterica

Front 28

Whats the mortality of typhoid fever?

Back 28

10-15%

Front 29

What are the signs and symptoms of typhoid fever?

Back 29

Systemic illness due to infection with salmonella typhi or salmonella paratyphi. Evande neutrophils = systemic spread. Survive/replicate in macrophages and monocytes = symptomatic phase ie focal infections at any body site (osteomyelitis, endocarditis, pneumonia, pyelonephritis, meningitis, cholecystitis, hepatic inflamm)

Front 30

Whats the timeline for Typhoid Fever Symptoms?

Back 30

Week 1 = high fever, headache, abd. pain, enlarged spleen, rose spots on chest/trunk

Week 2 = More continuous fever

Week 3 = Typhoidal state - altered mental state, intestinal involvement ie diarrhea

Week 4 = Fever Decreases and pt starts to recover

Front 31

Pt comes in with history of having eaten beef contaminated with fecal matter. They present with an altered mental state and bloody diarrhea. What week of salmonella typhi fever are they probably in?

Back 31

3

Front 32

Pt presents with recent history of having eaten chicken contaminated with feces. They are feverish, have an enlarged spleen, and you notice rose spots on trunk and chest. What week of salmonella poisoning are they likely in?

Back 32

1

Front 33

What organism can Typhoid salmonella infect and then re-seed the GI tract with an infection?

Back 33

gallbladder

3% of pts become chronic carriers

Front 34

Salmonella uses what mechanism to invade GI?

Back 34

bacterial-mediated endocytosis ie Type III secretion system. (Also used by Shigella, EHEC, EIEC, and EPEC)

Due to profound actin cytoskeletal rearrangements

Front 35

What does salmonella use to invade the gut?

Back 35

cytoskeleton ie Type III secretion system = bacterial proteins induce actin cytoskeletal rearrangements enabling bacterial up-take

Front 36

How does Salmonella prevent itself from being eaten by host defenses?

Back 36

Type III secretion system and bacterial proteins enable it to prevent phagolysosome fusion and escape from vacuole

Front 37

Once salmonella replicates in the vacuole, what does it do to cell?

Back 37

Escapes vacuole and kills cell --> migrates to mesenteric lymph node --> Thoracic duct --> Blood Bacteremia --> Liver, spleen, bone marrow

Front 38

How does the Vi capsid virulence factor of Salmonella work?

Back 38

Prevents TLR4 activation = prevents complement deposition (opsonization) and prevents complement-mediated phagocytosis by macrophages

Inc. bacterial resistance to peroxide, a host defense

Provides resistance to complement activation via classical pathway and complement-mediated lysis

Front 39

After infected, if a macrophage in infected with Salmonella enterica serotype enteriditis, what happens?

Back 39

Macrophage transports bact. to mesenteric lymph node. Nothing more will happen, b/c the strain that infected the macrophage is not typhi or paratyphi ie ONLY the serotypes that cause typhoid fever survive in the macrophages to establish systemic infection

Front 40

If a macrophage is infected with typhi or paratyphi, what happens?

Back 40

Macrophage transports bact. to mesenteric lymph node

serotypes that cause typhoid fever survive in the macrophages to establish systemic infection

From mesenteric lymph nodes, bact, enter thoracic duct and enter bloodstream causing transient bacteremia

Front 41

Whats the treatment for a gastroenteritis salmonella poisoning?

Back 41

Self-limited, so just fluids

Front 42

Whats the tx for typhoid fever caused by salmonella typhi or salmonella paratyphi?

Back 42

Abx

Front 43

All invasive infections, whether non-typhoid or typhoid-fever causing require what treatment?

Back 43

Abx