Gi: Peterson Gi Infections

Front 1

How is Vibrio cholerae primarily transmitted?

Back 1

Contaminated drinking water, but V. parahaemolyticus causes seafood based infections in the US

Front 2

What are the only animal reservoirs for V. cholerae?

Back 2

Shell fish and plankton

Front 3

Are Vibrio invasive?

Back 3

No, remain within the lumen

Front 4

What are necessary for colonization of Vibrio?

Back 4

flagellar proteins

Front 5

What is the Cholera Toxin composed of?

Back 5

5B subunit and 1A subunit

Front 6

The B subunit of the Cholera Toxin bind to ________ on the cell surface, and is transported into the cell to the ER by retrograde transport

Back 6

GM1 ganglioside (The A subunit is then reduced by disulfide isomerase and it unfolds)

Front 7

Stools have a "rice-water" appearance and have a "fishy" odor

Back 7

Vibrio

Front 8

Most deaths due to Vibrio occur within ___hours of presentation

Back 8

24

Front 9

Gram -, comma shaped, flagellated bacteria often associated with traveler's diarrhea

Back 9

Campylobacter jejuni

Front 10

MC bacterial enteric pathogen in developed countries

Back 10

Campylobacter jejuni

Front 11

What are most infections of Campylobacter jejuni associated with?

Back 11

Most infections are associated with improperly cooked chicken, but may be associated with unpasteurized milk or contaminated water.

Front 12

Dysentery with Campylobacter jejuni is associated with what?

Back 12

invasion

Front 13

When does an enteric fever occur with Campylobacter jejuni?

Back 13

when bacteria proliferate within the lamina propria and mesenteric lymph nodes

Front 14

In people with HLA-B27, what may Campylobacter infection cause?

Back 14

A reactive arthritis

Front 15

Besides reactive arthritis, what other extra-GI complications can be seen in a Campylobacter infection?

Back 15

Erythema nodosum and Guillain- Barre (Antibodies cross-react with peripheral and central nervous system gangliosides leading to flaccid paralysis.)

Front 16

Cryptitis

Back 16

PMNs within the epithelium (Seen in Campylobacter); crypt abscesses are also seen

Front 17

How do you differentiate a Campylobacter infection form Inflamatory Bowel Disease?

Back 17

Architecture IS maintained with a Campylobacter infection. (In IBD, architecture is NOT maintained)

Front 18

The only known reservoir of Shigella

Back 18

Humans

Front 19

How is Shigella transmitted?

Back 19

Only need a few orgs to spread, so person to person and HIGHLY transmissible by the fecal-oral route or water contamination

Front 20

Gram negative non-motile non-encapsulated bacilli, facultative anaerobes that are closely related to enteroinvasive E. coli

Back 20

Shigella

Front 21

Is Shigella motile?

Back 21

NO

Front 22

Where do most Shigella infections occur in the US and Europe?

Back 22

Day cares, travelers, nursing homes

Front 23

What is a reason for Shigella's very low effective dose?

Back 23

It is resistant to gastric acids

Front 24

The bacteria proliferate intacellularly, escape into the lamina propria, and are phagocytosed by macrophages

Back 24

Shigella

Front 25

Carry a virulence plasmid, encoding a type III secretion system allowing for direct injection of bacterial protein into the host cell.

Back 25

Shigella spp. & Salmonella

Front 26

Shigella mostly involves what part of the colon?

Back 26

Left colon

Front 27

Possible morphology of Shigella

Back 27

Epithelium is hemorrhagic and ulcerated. Psuedomembranes may be present.
The ulcers may coalesce leading to confusion with inflammatory bowel disease.

Front 28

3 sx of Reiter syndrome (HLA-B27, pts ages 20-40)

Back 28

Sterile arthritis, Urethritis, Cojuctivitis (Shigella)

Front 29

Complications may include Reiter Syndrome and HUS

Back 29

Shigella (Note that Yersinia may also cause Reiter Syndrome)

Front 30

Antidiarrheals are CONTRA in this infection as they prolong the disease

Back 30

Shigella

Front 31

Salmonella infections peak in what seasons?

Back 31

Summer and fall

Front 32

Like Shigella, possess a virulence gene that encodes for a type III secretion system.

Back 32

Salmonella (The secreted proteins activate Rho GTPase triggering actin re-arrangement and bacterial uptake into phagosomes where they proliferate.)

Front 33

____Therapy is NOT recommended in Salmonella infections as it will prolong the carrier state

Back 33

Antibiotic

Front 34

Org that causes Typhoid fever/Enteric fever

Back 34

Salmonella typhi (endemic)/paratyphi (travelers)

Front 35

Infection is strongly associated with travel to India, Mexico, the Philippines, Pakistan, El Salvador, and Haiti.

Back 35

Salmonella typhi/paratyphi

Front 36

Gallbladder colonization may occur causing gallstones and a chronic carrier state.

Back 36

Salmonella typhi/partyphi

Front 37

Morphology may show enlarged Peyer's patches forming sharply delineated plateau-like elevations

Back 37

Salmonella typhi (Mesenteric lymph nodes also enlarge); Yersinia may also display Peyer's patch hyperplasia

Front 38

Mucosal shedding causes ulcers oriented along the axis of the ileum.

Back 38

Salmonella typhi

Front 39

The liver contains foci of necrosis, with aggregates of macrophages

Back 39

Salmonella typhi (aggregates of macs are called typhoid nodules)

Front 40

Patients experience a symptomatic disease of anorexia, nausea, vomiting, pain, bloating, and bloody diarrhea; followed by an asymptomatic phase. This gives way to bacteremia with fever and flu-like symptoms.

Back 40

Salmonella typhi

Front 41

Rose spots ( eryrthematous maculopapular lesions) may be present on the abdomen and chest.

Back 41

Salmonella

Front 42

Iron enhances virulence and stimulates systemic dissemination

Back 42

Yersinia (Individuals with hemolytic anemia or hemochromatosis are more like to develop sepsis.)

Front 43

Invades M cells by using adhesion proteins (adhesins).
Binds host cell B1 integrins.
Genes are present which encodes for iron uptake.

Back 43

Yersinia

Front 44

What part of the GI tract does Yersinia like?

Back 44

R colon, ileum and appendix

Front 45

May mimic appendicitis is teenagers and young adults.

Back 45

Yersinia

Front 46

Post infectious complication of Yersinia

Back 46

Arthritis, Reiter syndrome, myocarditis, glomerulonephritis, Thyroidits

Front 47

Extra GI sx of Yersinia

Back 47

Pharyngitis, Arthralgia, Erythema nodosum (EN also seen in Campylobacter)

Front 48

Principle cause of traveler's diarrhea

Back 48

Enterotoxigenic E. Coli (ETEC)

Front 49

Produces a heat labile toxin (LT) and heat stabile toxin (ST) that will both induce water and Cl- secretion

Back 49

ETEC (The LT is like cholera, activating adenylate cyclase/cAMP) (The ST activates cGMP)

Front 50

Produces a shiga-like toxin leading to bloody diarrhea and hemolytic uremic syndrome.

Back 50

Enterohemorrhagic E. Coli (EHEC)

Front 51

What type of E. Coli is similar to Shigella, does NOT produce toxins and invades the epithelial cell?

Back 51

Enteroinvasive E. Coli (EIEC)

Front 52

Type of E. Coli that attaches to epithelial cells via Adherence Fimbriae, aided by Dispersin (protein)

Back 52

Enteroaggregative E. Coli (EAEC)

Front 53

What main bug causes Pseudomembranous Colitis? (Also known as antibiotic associated colitis)

Back 53

Clostridium Difficile; may also be assoc with Shigella, C. perfringens or staph aureus)

Front 54

Crypts are distended by a mucopurulent exudate that looks like an “eruption from a volcano.” ; Fibrin thrombi may be present in caps; LP contains tons of PMNs

Back 54

Pseudomembranous Colitis (C. diff pretty much)

Front 55

Tx for Pseudomembranous Colitis

Back 55

Metronidazole or Vancomycin

Front 56

A rare chronic multivisceral disease caused by a gram positive rod-shaped bacillus seen by electron microscopy

Back 56

Whipple Disease (Tropheryma whippelii)

Front 57

Villous expansion of the intestinal villi cause a shaggy gross appearance.

Lymphatic dilation is present, leading to the appearance of white to yellow plaques in the mucosa.

Back 57

Whipple Disease

Front 58

Triad of diarrhea, weight loss and malabsorption

Back 58

Whipple Disease

Front 59

How do you tell the difference between Whipple disease and and mycobacterial infection?

Back 59

Mycobacterium are acid fast

Front 60

Characteristics of Norovirus

Back 60

ssRNA

Front 61

Characteristics of Rotavirus

Back 61

Encapsulated virus with a ds RNA genome

Front 62

The most common cause of childhood diarrhea and diarrhea related mortality worldwide.

Back 62

Rotavirus

Front 63

Selectively infects and destroys mature enterocytes, and the villus surface is repopulated my immature secretory cells.

Back 63

Rotavirus

Front 64

The 2nd most common cause of pediatric diarrhea. Also causes it in immunocompromised pts

Back 64

Adenovirus (nuclear inclusions can be seen on bx)

Front 65

Unique in that it does not need a stage outside of the body. It can hatch with in the intestine, invade, and cause autoinfection. Hence infections can persist for life, and become over-whelming.

Back 65

Strongyloides

Front 66

Chronic infections cause iron deficiency anemia.

Back 66

Necator duodenale and Acylostoma duodenale

Front 67

Dx of Necator duodenale and Acylostoma duodenale

Back 67

Finding eggs in stool

Front 68

Name 3 parasites that do NOT invade the host

Back 68

Trichuris trichiura (whip worm) and Enterobus vermicularis (pin worms) and Tape worms; NO eosinophilia bc there is NO invasion!

Front 69

Adult worms reside within the mesenteric veins.

Back 69

Schistosomiasis

Front 70

When is eosinophilia present?

Back 70

When invasion occurs

Front 71

Cysts have a chitin wall and 4 nuclei, and are resistant to gastric acid.

Back 71

Entamoeba histolytica

Front 72

What part of the GI tract is Amebiasis MC?

Back 72

Cecum and ascending colon (Entamoeba histolytica)

Front 73

This recruits neutrophils, causes tissue damage, and produces “flask-shaped,” ulcer.

Back 73

Entamoeba hisolytica

Front 74

Parasite that is an obligate fermenter of glucose

Back 74

Amebae (lack mito and Krebs cycle)

Front 75

The most common pathogenic parasitic infection in humans.

Back 75

Giardia Lamblia

Front 76

Secretory IgA and IL-6 are needed for clearance of infection.

Back 76

Giardia

Front 77

The oocysts are resistant to chlorine, so may be present in treated, but unfiltered water.

Contaminated drinking water is the most common mode of transmission.

Back 77

Cryptosporidium

Front 78

The ingested cysts are activated by gastric acid.
The release sporozoites are motile, and attach to the enterocyte brush border, where they elicit actin polymerization.

Back 78

Cryptosporidium

Front 79

Persistent infection in children may cause villous atrophy.

Back 79

Cryptosporidium