Enterobacteriaceae - intro and E. coli

Question 1

Characteristics of Enterobacteriaceae (4)

Answer 1

Gram negative rods
LPS
Ferment glucose
oxidase negative

Question 2

Serological typing

Answer 2

O Ag (polysaccharide portion of LPS)
K (capsular) Ag
H (flagella) Ag

Question 3

Enterobacteriaceae with lac operon (lactose fermenting)

Answer 3

Klebsiella
Escherichia
Enterobacter

Question 4

What is the common Ag?

Answer 4

Polyssaccharide core

Question 5

What causes immune response?

Answer 5

Lipid A (endotoxin)

Question 6

Most common cause of bacteremia?

Answer 6

E. Coli

Question 7

Most common cause of GI tract infection?

Answer 7

Salmonella

Question 8

Most common cause of UTI?

Answer 8

E. coli

Question 9

Major cytokines induced by endotoxins

Answer 9

TNF alpha
IL-6
IL-1

Question 10

Which virulence factor goes directly into host cell?

Answer 10

Type III secretion system

Question 11

What fraction of bacteremia is caused by enterobacteriaceae?

Answer 11

1/3

Question 12

What percent of bacteremia due to Enterobacteriaceae is due to E. coli? Klebsiella? Enterobacter?

Answer 12

45%
22%
20%

Question 13

What percentage of UTI is caused by Enterobacteriacae?

Answer 13

70%

Question 14

Diseases caused by E. coli

Answer 14

Gastroenteritis
Hemolytic-uremic syndrome
UTI
Neonatal meningitis
Septicemia

Question 15

5 groups of E. coli that cause gastroenteritis

Answer 15

enterotoxigenic, enteropathogenic, enteroaggregative (SI)

Enteroinvasive, enterohemorrhageic (colon)

Question 16

Enterotoxigenic E. coli (ETEC)

Answer 16

plasmid-mediated
non-invasive
Fimbrial adhesins, CFA I and II

Question 17

Enterotoxins released by ETEC

Answer 17

Heat labile (LT)
Heat stable (ST)

Question 18

What is the cause of watery diarrhea due to ETEC

Answer 18

Enterotoxins cause iron channel to open, resulting in fluid secretions

Question 19

does ETEC cause Inflammation? Fever?

Answer 19

No

No

Question 20

Enteropathogenic E. coli (EPEC)

Answer 20

Non fibrial adhesion
Moderately invasive
Attachment-Effacement 
Bundle forming pilus
Destruction of microvilli

Question 21

What is the most significant thing about EPEC

Answer 21

Destruction of microvilli

no toxins produced

underdeveloped countries

Question 22

Enterohemorrhagic E. coli (EHEC)

Answer 22

Moderately invasive

Shiga-like toxin /verotoxin

Question 23

What does EHEC produce? What does it do?

Answer 23

Shiga-like toxin
cytotoxic to intestinal villi and colon epithelial cells
stops protein synthesis and causes necrosis

Question 24

What is significant about diarrhea caused by EHEC?

Answer 24

Bloody

Question 25

Is there inflammation with EHEC?

Answer 25

Yes - intense

Question 26

Does EPEC cause inflammation? fever?

Answer 26

Yes - some | No fever

Question 27

Enteroinvasive E. coli (EIEC)

Answer 27

nonfimbrial adhesions, omp invasive M cells Large plasmid no shiga toxin

Question 28

Characterize diarrhea caused by EIEC

Answer 28

dysentery - | mucous, bloody

Question 29

EIEC cause inflammation? Fever?

Answer 29

Yes, yes

Question 30

Enteroaggregative E. coli (EAggEC)

Answer 30

no adhesins - GVVPQ fimbriae noninvasive "Biofilm" Produce ST-like toxin and alpha hemolysin no fever

Question 31

What is different about diarrhea caused by EAggEC?

Answer 31

Chronic/persistent diarrhea in children without immunizations (non bloody)

Question 32

Common cause of UTI

Answer 32

E. coli | 80% community acquired) (40% hospital - Abx resistance common

Question 33

Community- acquired UTI are _____ infections

Answer 33

ascending

Question 34

What are some bacterial attributes/host factors that cause UTI?

Answer 34

Bacterial: P fimbriae (pilus), urease, hemolysins Host: short urethra in women, catheterization, compromised immunity etc

Question 35

Virulence factors of Uropathogenic E. coli

Answer 35

P fimbria - pyelonephritis associated pili (PAP pili) binds P blood group Ag with D-galactose-D-galactose residue

Question 36

Treatment of enteric pathogen

Answer 36

fluid replacement is the main thing. don't want dehydration infection control in hospital Abx therapy requires test for sensitivity to avoid resistance