Enterics Flashcards by Walker Short

What is MacConkey agar?

contains bile salts to suppress the growth of most gram (+) organisms
suppresses growth of Neisseria & Haemophilus
also contains lactose & a pH indicator

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What type of agar plates do we use to test lactose fermentation in Gm (-) organisms?

MacConkey agar

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Which surface antigen on Gm (-) organisms confers motility?

Flagella

(H Antigen)

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What do fibriae do for Gm (-) bacteria?

allows attachment to host cell
exhibit phase variation

(used for UTI)

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What does it mean if bacteria can form a biofilm?

-they have a capsule

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Why can’t organisms that have lipooligosaccharide grow in the gut?

-sensitive to bile salts

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What infection is caused by bacteria with P-fimbriae?

Pyelonephritis

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What does LPS do to the host?

Activates the sepsis cascade

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What are siderophores?

allow Gm (-) bacteria to scavenge Fe from environment
Gm (-) bacteria need iron to live

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What is the K antigen a part of?

-the gram (-) capsule

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What diseases are caused by Klebsiella?

UTI
Pneumonia
multiple nosocomia infections (biliary infection, peritonitis, wound infxn)

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When are Morganella and Providencia infections seen?

-individuals with long-term catheters

*very close cousins of Proteus

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What diseases are caused by Proteus mirabilis?

UTI
Staghorn calculus

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What diseases are caused by Citrobacter?

Catheter associated UTI
Brain abscess in neonates

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What mediates adhesion of E. Coli to intestinal mucosa?

Fimbriae (Pili)

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In what organism do we see Hemolytic uremia syndrome (HUS)?

Enterohemorrhagic E. Coli (EHEC)
Shigella

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What are the three components of Hemolytic uremic syndrome?

Renal failure
Hemolytic anemia
Thrombocytopenia

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Pt has renal failure, hemolytic anemia, and thrombocytopenia. What organism are we thinking?

Enterohemorrhagic E. Coli (EHEC)
Shigella

* these are the components of Hemolytic uremic syndrome, seen in EHEC infection

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What diseases are caused by Enteropathogenic E. Coli (EPEC)?

-acute diarrhea in infants

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What diseases does Enteroaggregative E. Coli (EAEC) cause?

chronic diarrhea & malnutrition in developing countries
# 2 travelers diarrhea

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How do we identify Enteroaggregative E. Coli (EAEC)?

stacked brick adherence to tissue culture cells in Hep-2 cell assay

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What diseases are caused by Enteroinvasive E. Coli?

diarrhea

E. coli only causes neonatal meningitis if it has ________.

K antigen

E. coli’s heat Labile toxin increases c_MP.

cAMP

E. coli's heat Stable toxin increases c\_MP levels.

cGMP

Lactose fermenters turn _________ on mackonkey agar.

Pink

What infections are caused by klebsiella?

- lobar pneumonia - UTI

To treat klebsiella you need to use _________ because all klebsiella are ampicillin resistant.

B lactamase inhibitors

Is serratia a normal part of the human fecal flora?

A disk approximation test is used to see if there is ________ in __________ (bacteria).

- induced resistance - Enterobacter

Some subtypes of Enterobacter express a _______ in response to certain antibiotics.

B-lactamase

"swarming on blood agar"

Proteus

What is the treatment for proteus?

Sulfonamides

Biggest worry about citrobacter?

Brain abscesses

What are the 2 bugs that cause enteric fever?

- salmonella - yersinia

Which strain of E. coli is the most common cause of outbreaks of bloody diarrhea?

O157:H7 EHEC

"LEE pathogenecity island"

STEC & EHEC

Antibiotics are contraindicated in diarrhea caused by \_\_\_\_\_\_\_, becuase it will cause a massive release in toxins, resulting in HUS.

EHEC

Shiga toxin binds to the ________ portion of ribosomes, and inhibits translation.

60s

How do people get infected with Shigella?

Ass-to-mouth

Why is the infectious dose of Shigella super low? (10-100 organisms)

It is acid-stable

What are the virulence factors of Shigella?

- Invasive (more important) uses actin to propel itself - Shiga toxin

Shigella causes HUS more commonly in \_\_\_\_\_\_\_\_\_.

young children

How are shigella and Listeria similar?

- Both invade M cells - Both use Host's actin to propel themselves

Salmonella is (motile/non-motile), while Shigella is (motile/non-motile).

Salmonella = motile Shigella = non-motile

\_\_\_\_\_\_\_\_\_ is the #1 cause of osteomyelitis in patients with sickle cell.

Salmonella typhi

This diarrhea causing bug is carried by reptiles and amphibians.

Salmonella

"Rose colored macules"

Salmonella typhi

Salmonells _______ likes to live in the gallbladder.

Salmonella typhi

Recurrent salmonella is an \_\_\_\_\_-defining illness.

AIDS

Yersinia enterocolitica is commonly transfered via \_\_\_\_\_\_\_.

Puppy poop

Yersinia doesn't make \_\_\_\_\_\_\_\_\_. Thus, iron overload is a risk factor for infection.

Siderophores

Disease caused by Yersinia is exacerbated by \_\_\_\_\_\_\_\_\_.

abscence of a spleen, or sickle cell

Infection with this bug causes RLQ pain, and is often indistinguishable from acute appendicitis.

Yersinia enterocolitica