Enterobacteriacae Flashcards
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
What type of agar plates do we use to test lactose fermentation in Gm (-) organisms?
MacConkey agar
Which surface antigen on Gm (-) organisms confers motility?
Flagella
(H Antigen)
What do fibriae do for Gm (-) bacteria?
- allows attachment to host cell
- exhibit phase variation
(used for UTI)
What does it mean if bacteria can form a biofilm?
-they have a capsule
Why can’t organisms that have lipooligosaccharide grow in the gut?
-sensitive to bile salts
What infection is caused by bacteria with P-fimbriae?
Pyelonephritis
What does LPS do to the host?
Activates the sepsis cascade
What are siderophores?
- allow Gm (-) bacteria to scavenge Fe from environment
- Gm (-) bacteria need iron to live
What is the K antigen a part of?
-the gram (-) capsule
What diseases are caused by Klebsiella?
- UTI
- Pneumonia
- multiple nosocomia infections (biliary infection, peritonitis, wound infxn)
When are Morganella and Providencia infections seen?
-individuals with long-term catheters
*very close cousins of Proteus
What diseases are caused by Proteus mirabilis?
- UTI
- Staghorn calculus
What diseases are caused by Citrobacter?
- Catheter associated UTI
- Brain abscess in neonates
What mediates adhesion of E. Coli to intestinal mucosa?
Fimbriae (Pili)
In what organism do we see Hemolytic uremia syndrome (HUS)?
- Enterohemorrhagic E. Coli (EHEC)
- Shigella
What are the three components of Hemolytic uremic syndrome?
- Renal failure
- Hemolytic anemia
- Thrombocytopenia
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
What diseases are caused by Enteropathogenic E. Coli (EPEC)?
-acute diarrhea in infants
What diseases does Enteroaggregative E. Coli (EAEC) cause?
- chronic diarrhea & malnutrition in developing countries
- # 2 travelers diarrhea
How do we identify Enteroaggregative E. Coli (EAEC)?
stacked brick adherence to tissue culture cells in Hep-2 cell assay
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?
no
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
