INFECTIOUS AGENTS - Urinary Tract Pathogens Flashcards
What are the three different urinary tract infections (UTIs)?
Urethritis
Cystitis
Pyelonephritis
What is urethritis?
Infection of the urethra
What is cystitis?
Infection of the bladder
What is pyelonephritis?
Ascending infection of the bladder, resulting in infection of the kidneys
What is the difference between a simple and a complicated UTI?
A simple UTI is infection of a normal urinary tract whereas a complicated UTI is an infection of an abnormal urinary tract
What are four examples of things that contribute to a complicated UTI?
Struvite calculi (stones)
Surgery
Pregnancy
Anatomical abnormalities
Which pathogen most commonly causes UTIs?
Escherichia coli (E. coli)
What is the collective name for the species of E. coli which cause UTIs?
Uropathogenic E. coli (UPEC)
Where does uropathogenic E. coli (UPEC) originate from?
The gastrointestinal system
List five host pre-disposing factors which make individuals more susceptible to UTIs
Female animals
Diabetes
Pregnancy
Anatomical defects
Vesico-ureteric reflux
Why are females animals more susceptible to UTIs?
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
Pregnant animals often have asymptomatic bacteriuria. Why is it so important to test for and treat this?
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
What is vesico-ureteric reflux?
Vesico-ureteric reflux is the reflux of the urine from the bladder into the kidneys, causing pyelonephritis
(T/F) Most UTIs are caused by a single bacterial species
TRUE
When are you more likely to see a UTI caused my multiple species of bacteria?
You are more likely to see a UTI caused my multiple species of bacteria in a complicated infection or after inserting a urethral catheter
Describe briefly the pathogenesis of uropathogenic E. coli (UPEC)
- Adherence
- Colonisation
- Evasion of host defences
- Damage of host tissue
Why is it essential for bacteria which cause UTIs to be able to adhere to the urinary tract epithelium?
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
Which virulence factors allow bacteria to adhere to the urinary tract epithelium?
Type 1 fimbriae
P-fimbriae
Which type of fimbriae is associated with uropathogenic E. coli (UPEC) strains which cause pyelonephritis?
P-fimbriae
Describe the three toxins secreted by UPEC bacteria
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
List the virulence factors of UPEC encoded on pathogenicity islands
P-fimbriae
Haemolysin
CNF-1
List the virulence factors of UPEC encoded on the core genome
Type 1 fimbriae
Specific O-antigens
Enterobactin siderophore
Urease enzyme is a virulence factor used by some species of bacteria which cause UTI infections, what is the function of urease?
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)
Which species’ of bacteria produce the urease enzyme?
Staphylococcus and Proteus produce urease
What is a biofilm often seen in UTIs?
A biofilm is the aggregation of bacteria to each other and the bladder wall (or sometimes a urinary catheter)
(T/F) Antibiotics can penetrate the biofilm
FALSE. Antibiotics CANNOT penetrate the biofilm
What allows UTIs to persist and recur?
The invasion of the urinary tract epithelial cells by UPEC bacteria allows to the persistence and recurrence of UTIs
What would classify a clinically significant urine sample when testing for a UTI?
A urine sample with a high number of one species of bacteria would be clinically significant
What are the clinical signs of a UTI?
Dysuria
Haematuria
Pyuria
Urinary incontinence
Which two virulence factors aid in the ascending migration of bacteria into the kidneys causing pyelonephritis?
Flagella and fimbriae
What are two clinical signs specific to pyelonephritis?
Arched back
Passing of blood and pus in the urine
What are the three corynebacteria which cause cystitis and pyelonephritis in cattle?
Corynebacteria. renale (C. renale)
Corynebacteria. pilosum (C. pilosum)
Corynebacteria. cystitidis (C. cystitidis)
Other than cystitis and pyelonephritis, what other infection can be caused by C. renale, C. pilosum and C. cystitidis?
Balanoposthitis
What are the virulence factors of C. renale?
Pili
Renalin
Urease
Caseinase
