Enterobacteriaceae

Question 1

Enterobacteriaceae spp.- Gram, where does it reside, spores?, o2,\

Answer 1

• Gram neg
• Reside in digestive tract (intra/extracellular)
• do not form spors
• faculatative anaerobes

Question 2

what is a common factor of enterobacteriaceae to secrete its toxins

Answer 2

Have needle like protein complexes called secretion systems that secrete exotoxins into host cells

Question 3

How do you differentiate different types of enterobacteriaceae (+ what do u use to do this)

Answer 3

Can ferment lactose into lactic acid in macconkeys agar (causing it to turn pink)

Question 4

What are the lactose fermenting enterobacteria (2)

Answer 4

• E. coli

- Klebsiella pneumoniae

Question 5

What are the non lactose fermenting enterobacteria (3)

Answer 5

Salmonella spp
Shigella
Yersinia

Question 6

Where does e coli usually reside + produce

Answer 6

Reside in colon normally

-produces vit K

Question 7

What human pathologies can e coli cause + how is it typically transfered

Answer 7

• Food poisining
• UTIs
• Peritonitis

-ingestion of food/drink contaminated w fecal matter

Question 8

What are the 3 main pathotypes of e coli (antigen they present + what does it mean)

Answer 8

O- LPS
H- flagellin
K- Capsul

Question 9

What is enterohemorrhagic e coli (EHEC) due to and whatt type of toxins does it produce (+ what do the toxins do)

Answer 9

Undercooked beef, unwashed vegs/eggs

Shigga toxins- disruption of gut endothelial cells

Question 10

What are symptoms enterohemorrhagic e coli (EHEC)

Answer 10

• Cramps/ watery diarrhea

- Hemolytic uremic syndrome (kidney failure)

Question 11

What is the cause of 95% of UTIs and what is the virulece factor of it

Answer 11

Uropathgenic e coli

• Virulence factors include P fimbriae and type I fimbriae which help bacteria attach to urinary tract epithelial cells
• inflamation triggered by LPS

Question 12

Klebsiella pneumoniae- lactose fermenting?, whos it mc in, assocuated syndrome

Answer 12

lactose fermenting

• mc in chronically ill hospital pts.
• Associated w ankylosing spindylititis (autoimune infection triggered by it)

Question 13

What is peritonitis and what is the mc cause of it

Answer 13

Damage to the digestive tract usually results in release of bacteria into the normally sterile peritoneum

-e coli mc cause

Question 14

What are the 2 subspecies of salmonella spp that cause salmonellosis + what foods is it caused by

Answer 14

Non typhoidal serotypes:

1. S typhimurium
2. S enteritidis

-Eggs, poultry, pork, beef, vegs contaminated w animal waste

Question 15

What subspecies of salmonella spp cause human disease

Answer 15

S. enterica

Question 16

Pathology of salmonellosis + when do symptoms appear

Answer 16

6-72hrs after exposure

Large numbers of bacteria enter digestive tract
Bacteria invade intestinal epithelial cells (replication) and induce a strong immune response (LPS, damage)

Question 17

What salmonella spp cause enteric (typhoid) fever (2)

Answer 17

Typhoidal serotypes

1. S typhi
2. S. paratyphi

Question 18

How is typoid fever transmitted and normal incubation period

Answer 18

Oral-fecal transmission (contaminated food/drink)

8-14 days

Question 19

What are the symptoms of typoid fever

Answer 19

w 1-2-high fever, diarrhea, tiredness, headache, loss of appetite, rash

w3-4- usual resolution

Question 20

Shigella- lactose fermenting?, flagella? what does it typically cause

Answer 20

Cause of shigellosis (food poisoning)

• non lactose fermenting
• no flagella

Question 21

transmission and typical incubation time of shigella

Answer 21

12-48 hrs

fecal-oral route
contaminated water, raw meats/vegs

Question 22

Pathology of shigellosis

Answer 22

Bacilli enter thru specialized epithelial cells called m cells and then can enter neighboring cells causing tissue damage thru LPS
-may produce shiga toxins

Question 23

Symptoms of shigellosis

Answer 23

Shigellosis usually presents with diarrhea (mild to severe, watery to dysentery) and abdominal pain.

Question 24

Yersinia spp: what are the 2 species of it and what do they produde

Answer 24

1. Yersinia enterocolitica–> yersiniosis
2. Yersinia Pestisis–> plague

-Capable of producing virulence factors that prevent production of immune factors (cytokines), increase resistance to phagocytosis and enhance intracellular survival.

Question 25

Yersiniosis- what is it, due to what, pathology

Answer 25

Type of food poisioning -insuficiently cooked pork/ contaminated milk Enters gut and migrates to gut lymphoid tissue where they replicate causing mucosal ulceration (bloody stool)

Question 26

Yersinia pestis (plauge)- how was it transmitted

Answer 26

Humans become infected through flea bites (regurgitate bacteria), direct contact with contaminated animal tissues (rats) or through inhalation of infectious aerosols

Question 27

what is the clinical presentation of yesinia pestis (plauge)

Answer 27

Bacteria carried to lympatic tissue where they replicate in large numbers - bubonic plaque due to enlarged lymph nodes - Bacteremia is comon causeing necrosis

Question 28

What is the clinical triade of autoimmune syndrome following bacteria inf

Answer 28

1. Eye inflamation 2. Inflammation of urethra/cervix 3. Arthritis of large jts.

Question 29

Reactive arthritis (reiters syndrome) due to what bac (2)

Answer 29

Salmonella spp | Shigella spp.

Question 30

What are the toxins enterotoxigenic e coli (ETEC) (2)

Answer 30

Heat labile enterotoxin | Heat stabile enterotoxin

Question 31

What does ETEC caused by and symptoms

Answer 31

Intense and prolonged secretion of ions (especially Cl-) leading to watery diarrhea with nausea and cramps