Urinary Tract Bacterial Pathogens Flashcards
Name 4 main urinary tract infections
• Urethritis- infection of urethra
• Cystitis- infection of bladder
• Pyelonephritis- ascending infection of kidney (travels up from bladder)
• Prostatitis- infection of prostate
What are the 2 types of urinary tract infections
Simple or complicated
Complicated- presence of stones, surgery, male sex, pregnancy, anatomical abnormalities
What are some host defences against urinary tract infection (UTI)
Urination/Micturition
Mucosal defence
Cell exfoliation
Normal microflora
Why is UTI more common in females?
Anatomical reason- in females there is a shorter distance for the infection to travel from the anus to the vagina and then up the urethra to the bladder
What are Pre-disposing host factors
Name some
Factors which make a host more susceptible to being infected
Female sex – short urethra
Diabetes
Pregnancy
Anatomical defects
Vesico-ureteric reflux
Usually single or multiple species caused UTI in dogs?
Single
Name the main pathogens causing UTI
Escherichia coli (37-55%) • Proteus
• Klebsiella
• Enterobacter
• Pseudomonas
• Staphylococcus, Streptococcus, Enterococcus
(23-30%)
What to remember about what staphylococci does
These organisms produce enzyme which breaks down urea to ammonia which causes ^ in urea pH which causes kidney/bladder stones
What can E.coli pathogen do to bladder epithelium
• Colonization
• Avoidance of host defence • Damage to host tissue
Clinical symptoms of UTI
dysuria (hurts to go), haematuria, pyuria (WBC/pus in urine), frequency, burning on micturition, dribbling etc
What’s the difference between bacterial lacking Fimbriae and having Fimbriae
Those lacking will get flushed away
Those with are able to adhere to epithelial cells, meaning they stay, colonise and multiply
Fimbriae characteristics
-shape
-mediate attachment to…
-bind what
-composed of…
-expression affected by what factors
• Long, thin structures 0.1-20um x 4-8 nm
• Mediate attachment to eucaryotic cells
• Bind carbohydrate residues: Lectins
• Composed of protein subunits (pilin)
• Specialised pilins at tip may act as adhesin
• Expression affected by environmental conditions, eg, not expressed at low temperature
• virulence factor
2 types of fimbriae in UTI
Type 1 fimbriae
P fimbriae
What is showing on this diagram
On anki
What is a biofilm in the bladder? what does it prevent?
Lots of pathogens stick together and adhere to surface/ epithelium
Prevents their flushing
Why does a biofilm make it difficult to treat an infection?
Prevents antibiotic penetration
Cystitis
-type of infection?
-caused by what?
-how does it colonize
-occurs when what occurs
Bladder infection
• Cystitis caused by UPEC results from transfer to the bladder by bacteria present in the rectum (carried in the gut)
• Multiplication of bacteria in the bladder
Occurs when;
• Host inflammatory response to UPEC occurs
• Tissue damage caused by UPEC occurs
Adherence of;
type 1 and P fimbriae
activates signalling pathways through what in each type?
P- activation through ceramide & TLR-4
Type 1- activation through TLR-4
UTI causes what in urine?
Blood
What do toxins cause
Bleeding and sloughing of epithelium in animal models
Lyses cells releasing nutrients
Modulates signalling pathways – cell cycle apoptosis and inflammation
Infection is cleared by…
• Cell exfoliation
• Neutrophils- release molecules that kill using
-Reactive nitrogen and oxygen species
• Other anti-bacterial compounds
Persistence of cystitis is facilitated by…
-mediated by…
-binds what
-leads to…
• Invasion of bladder epithelial cells by UPEC contributes to persistence of cystitis
• Mediated by type 1 fimbriae and FimH adhesin at tip
• Binds host cell integrins to facilitate cell invasion
• Leads to formation of intracellular bacterial communities (IBC)
-Persistence, chronic infection, recurrent UTI
How do you diagnose a UTI
Clinically then send sample to lab
-collecting urine sample from animal by using a urine pad and squeezing the pee out of it
One bacterial species in high numbers is…
Clinically significant
