UPEC

Question 1

What is the difference between bacteriuria, cystitis and pyelonephritis?

Answer 1

Bacteriuria is presence of bacteria in the urine, cystitis is bacteria present in bladder and pyelonephritis is bacterial infection in the kidneys

Question 2

What are the challenges to bacterial infection in the urinary tract?

Answer 2

The force of flow of urine, the physiochemical properties, the iron binding proteins in the urine, Tamm-Horsfall protein Toll-like receptor 4 which interacts with lipopolysaccharide to activate the immune system, cytokines which attract white blood cells released by infected cells, natural exfoliation of cells which may remove infected cells

Question 3

What is the Tamm-Horsfall protein?

Answer 3

A large molecular weight protein excreted by the kidneys that binds to bacteria so that is it unable to bind to host receptors

Question 4

What are the signs and symptoms of a UTI?

Answer 4

Dysuria, Frequent urination, Uregncy and hesitancy, cloudy or bad smelling urine, lower abdominal pain, mild fever, nausea and vomiting
Flank pain indicates a kidney infection

Question 5

What behavioural factors can increase susceptibility to urinary tract infections?

Answer 5

Sexual activity, Certain drugs, condom or female condom use

Question 6

What are the hospital factors that can increase susceptibility to urinary tract infections?

Answer 6

Urogenital surgery and urinary catheter use (due to formation of a biofilm)

Question 7

What is the biofilm process of bacterial proliferation?

Answer 7

Bacteria adhere to target tissues and then secrete a sticky substance which covers them preventing access to many outside molecules like cleaning agents or immune cells. After a period of growth the biofilm with then mature releasing the bacteria to spread and form new biofilms

Question 8

What may be the genetic susceptibility to UTIs?

Answer 8

A person who secretes blood antigens in fluids such as breast milk, saliva and sweat (known as an ABH secretor)

Question 9

What medical conditions can cause sucepsitbality to UTIs?

Answer 9

Diabetes, incontinence, congenital abnormalities, urinary obstruction, prior history of UTIs and estrogen deficiency

Question 10

What is the likelihood of a man experiencing a UTI during his lifetime?

Answer 10

10%-12%

Question 11

What is the likelihood of a woman experiencing a UTI during her lifetime?

Answer 11

40-50% with a 25% chance of experiencing a second UTI and a 3% chance that women will experience a third UTI within 3 months of treatment of the initial UTI

Question 12

What are the three methods for UTI diagnosis?

Answer 12

Urinalysis, Microscopy or culture

Question 13

What is the infection process in UTIs?

Answer 13

Access by contamination, adhesion and colonisation by pili outer membrane proteins and flagella, immune evasion, multiplication controlled by iron access and damage by both the bacterial virulence factors and inflammatory processes

Question 14

What is contained on PAI 1 of UPEC?

Answer 14

Alpha haemolysin, adhesion determinants, unidentified fimbrae, hemin utilization system

Question 15

What is contained on PAI 2 of UPEC?

Answer 15

P-related fimbrae, a-hemolysin, adhesions

Question 16

What is UPEC?

Answer 16

Urinary Pathogenic Escheria Coli

Question 17

What is contained on PAI 3 of UPEC?

Answer 17

S-fimbrae, Enterochelin sidosphore uptake system, iro iron uptake system

Question 18

What is contained on PAI 4 of UPEC?

Answer 18

Yersinia bactin iron acquisition system

Question 19

What is contained on PAI 5 of UPEC?

Answer 19

Capsular synthesis

Question 20

What is the role of adhesions in UTIs?

Answer 20

Enables the bacteria to adhere to both biotic and abiotic surfaces, Protects the bacteria from clearance by the host, required for uropathogenesis

Question 21

What pili is required to cause cystitis?

Answer 21

Type 1 pili (FimH)

Question 22

What pili is required to cause pyelonephritis?

Answer 22

Pap pili (PapG)

Question 23

How can UPEC adhesions allow invasion of the cell?

Answer 23

It allows entry on the back of normal process and is not directly controlled by the bacteria as there is a shuttling of fusiform vesicles in and out of the apical membrane of the bladder cell to regulate surface area of the bladder during urine accumulation

Question 24

What is the role of type 1 pili in UPEC?

Answer 24

It is found on the surface of most Enterobacteriaceae and binds to mannose containing receptors, carries a FimH adhesion and allows non selective binding to Tamm-horsfall, type I and IV collagen, Laminin and fibronectin

Question 25

What is the role of the P-pili in UPEC mediated pyelonephritis?

Answer 25

Uses Pap G as the tip adhesion binding to globobiose receptors on the kidney epithelium
P antigen is found on erythrocytes and other blood cells, endothelial cells, renal epithelium, fibroblasts, smooth muscle cells of the digestive tract and urogenital tissues

Question 26

How do UTIs gain iron to grow?

Answer 26

Through use of siderophores such as enterobactin, aerobactin, yersiniabactin
There is also haem uptake from ChuA and Hma

Question 27

What happens to UPEC infection if one iron acquisition pathway is knocked out?

Answer 27

The bacteria can still survive and cause disease as there are many redundancies due to the large number of iron acquisition systems it has available to it

Question 28

What are the toxins produced by UPEC?

Answer 28

Alpha hemolysin which alters the structural integrity of eukaryotic cells, damaging bladder epithelium and allowing the bacteria to invade deeper tissues

Question 29

How is lipolysaccharide a virulence factor of UPEC?

Answer 29

It is an endotoxin, with toxicity associated with the lipid A, this and the O antigens cause an inflammatory response of complement activation via the alternative pathway

Question 30

How is the capsule of UPEC a virulence factor?

Answer 30

It is made of polysaccharides and provides protection from the innate immune system as it inhibits complement activation and phagocytosis

Question 31

What is the model for UTI infection and persistence?

Answer 31

UPEC binds to the surface of a bladder cell by a type 1 pili and fusiform trafficking leads to entry into the bladder cell, the bacteria replicates intracellularly forming disordered bacterial clusters in the host cell cytoplasm forming an intracellular bacterial community which is organised into a tightly packed biofilm like state
Expoliation of cells can then lead to the bacteria detaching and flux within the bladder lumen as well as filamentous bacteria which may be difficult to phagocytose