INFECTIOUS AGENTS - Urinary Tract Pathogens

Question 1

What are the three different urinary tract infections (UTIs)?

Answer 1

Urethritis
Cystitis
Pyelonephritis

Question 2

What is urethritis?

Answer 2

Infection of the urethra

Question 3

What is cystitis?

Answer 3

Infection of the bladder

Question 4

What is pyelonephritis?

Answer 4

Ascending infection of the bladder, resulting in infection of the kidneys

Question 5

What is the difference between a simple and a complicated UTI?

Answer 5

A simple UTI is infection of a normal urinary tract whereas a complicated UTI is an infection of an abnormal urinary tract

Question 6

What are four examples of things that contribute to a complicated UTI?

Answer 6

Struvite calculi (stones)
Surgery
Pregnancy
Anatomical abnormalities

Question 7

Which pathogen most commonly causes UTIs?

Answer 7

Escherichia coli (E. coli)

Question 8

What is the collective name for the species of E. coli which cause UTIs?

Answer 8

Uropathogenic E. coli (UPEC)

Question 9

Where does uropathogenic E. coli (UPEC) originate from?

Answer 9

The gastrointestinal system

Question 10

List five host pre-disposing factors which make individuals more susceptible to UTIs

Answer 10

Female animals
Diabetes
Pregnancy
Anatomical defects
Vesico-ureteric reflux

Question 11

Why are females animals more susceptible to UTIs?

Answer 11

The female urethra is shorter than the male urethra and is thus closer to the bladder so the bacteria doesn’t have as far to travel to reach the bladder

Question 12

Pregnant animals often have asymptomatic bacteriuria. Why is it so important to test for and treat this?

Answer 12

Asymptomatic bacteriuria is the presence of bacteria in the urine. If left untreated, this predisposes the female animal to pyelonephritis which can allow the bacteria to enter the blood, causing bacteraemia and sepsis

Question 13

What is vesico-ureteric reflux?

Answer 13

Vesico-ureteric reflux is the reflux of the urine from the bladder into the kidneys, causing pyelonephritis

Question 14

(T/F) Most UTIs are caused by a single bacterial species

Answer 14

TRUE

Question 15

When are you more likely to see a UTI caused my multiple species of bacteria?

Answer 15

You are more likely to see a UTI caused my multiple species of bacteria in a complicated infection or after inserting a urethral catheter

Question 16

Describe briefly the pathogenesis of uropathogenic E. coli (UPEC)

Answer 16

1. Adherence
2. Colonisation
3. Evasion of host defences
4. Damage of host tissue

Question 17

Why is it essential for bacteria which cause UTIs to be able to adhere to the urinary tract epithelium?

Answer 17

It is essential for bacteria which cause UTIs to be able to adhere to the urinary tract epithelium to prevent the bacteria from being flushed out by urine

Question 18

Which virulence factors allow bacteria to adhere to the urinary tract epithelium?

Answer 18

Type 1 fimbriae
P-fimbriae

Question 19

Which type of fimbriae is associated with uropathogenic E. coli (UPEC) strains which cause pyelonephritis?

Answer 19

P-fimbriae

Question 20

Describe the three toxins secreted by UPEC bacteria

Answer 20

Haemolysin: pore forming toxin
CNF-1: causes inflammation, allows for bacterial cell uptake and apoptosis of epithelial cells
Secreted autotransporter toxin (SAT): vacuolating cytotoxin for epithelial cells

Question 21

List the virulence factors of UPEC encoded on pathogenicity islands

Answer 21

P-fimbriae
Haemolysin
CNF-1

Question 22

List the virulence factors of UPEC encoded on the core genome

Answer 22

Type 1 fimbriae
Specific O-antigens
Enterobactin siderophore

Question 23

Urease enzyme is a virulence factor used by some species of bacteria which cause UTI infections, what is the function of urease?

Answer 23

Urease enzyme breaks down urea into ammonia which increases the pH of the urine. This causes components of the urine to precipitate and form struvite calculi (bladder and kidney stones)

Question 24

Which species’ of bacteria produce the urease enzyme?

Answer 24

Staphylococcus and Proteus produce urease

Question 25

What is a biofilm often seen in UTIs?

Answer 25

A biofilm is the aggregation of bacteria to each other and the bladder wall (or sometimes a urinary catheter)

Question 26

(T/F) Antibiotics can penetrate the biofilm

Answer 26

FALSE. Antibiotics CANNOT penetrate the biofilm

Question 27

What allows UTIs to persist and recur?

Answer 27

The invasion of the urinary tract epithelial cells by UPEC bacteria allows to the persistence and recurrence of UTIs

Question 28

What would classify a clinically significant urine sample when testing for a UTI?

Answer 28

A urine sample with a high number of one species of bacteria would be clinically significant

Question 29

What are the clinical signs of a UTI?

Answer 29

Dysuria
Haematuria
Pyuria
Urinary incontinence

Question 30

Which two virulence factors aid in the ascending migration of bacteria into the kidneys causing pyelonephritis?

Answer 30

Flagella and fimbriae

Question 31

What are two clinical signs specific to pyelonephritis?

Answer 31

Arched back
Passing of blood and pus in the urine

Question 32

What are the three corynebacteria which cause cystitis and pyelonephritis in cattle?

Answer 32

Corynebacteria. renale (C. renale)
Corynebacteria. pilosum (C. pilosum)
Corynebacteria. cystitidis (C. cystitidis)

Question 33

Other than cystitis and pyelonephritis, what other infection can be caused by C. renale, C. pilosum and C. cystitidis?

Answer 33

Balanoposthitis

Question 34

What are the virulence factors of C. renale?

Answer 34

Pili
Renalin
Urease
Caseinase