22-02-23 – Urinary Tract Infections Flashcards
Learning outcomes
- Identify which pathogens commonly cause UTIs
- Recognise main presenting symptoms of a patient with UTI
- Outline the clinical and laboratory diagnosis of UTIs
- Explain the complications that may arise if a UTI is left untreated
- Recognise the assoociation between different bacterial species and certain at-risk patients who develop UTIs
- Understand how the host is protected against UTIs
- Recognise the role of various bacterial virulence factors in the causation of UTIs
- Identify the most appropriate choice of treatment(s) to successfully treat UTIs
Definitions
* Micturition
* Dysuria
* Bacteriuria
* Haematuria
* Pyelonephritis
* Cystitis
* Urethritis
* Prostatitis
- Definitions
- Micturition - urination
- Dysuria - pain on urination
- Bacteriuria - presence of bacteria in the urine
- Haematuria - presence of blood in urine
- Pyelonephritis - kidney infection
- Cystitis - infection confined to the bladder
- Urethritis - inflammation of the urethra
- Prostatitis - prostate infection
How common are UTIs?
What is their incidence?
What % of antimicrobial prescriptions in primary care do they make up?
Which sex are they most common in? How common are they in women?
What age do UTIs primarily occur in in men?
- UTIs are one of the commonest infections.
- UTI incidence is 50,000 per million persons per year
- They account for 15% of all antimicrobial prescriptions in primary care.
- They are more common in women than men
- 50% of adult women have ≥1 UTI in lifetime, particularly common in postmenopause.
- Occur inn men primarily >50 years of age
What % of UTIs are single are isolated attacks?
What % of UTIs are recurrent attacks?
- 90% of UTIs are single or isolated attacks
- 10% of UTIs are recurrent attacks:
1) 20% of these recurrent attacks are relapsed, meaning infection occurs from a different microorganism from the one before
2) 80% of recurrent attacks are reinfections, meaning they are caused by the same microorganism as the infection before
What are 6 signs and symptoms of Lower UTIs?
What are 3 signs and symptoms of Infections of pelvis and kidney (acute pyelonephritis)?
- 6 signs and symptoms of Lower UTIs:
1) Frequency of micturition
2) Urgency to urinate
3) Dysuria
4) Suprapubic pain & tenderness
5) Haematuria
6) Smelly / cloudy urine - 3 signs and symptoms of Infections of pelvis and kidney (acute pyelonephritis)?
1) Loin pain & tenderness
2) High fever
3) Systemically unwell
What are 11 predisposing factors for UTIs?
- 11 predisposing factors for UTIs:
1) Obstruction: calculi, tumors, benign prostate hyperplasia
2) Vesicoureteral reflux (VUR) – urine going back up the ureter
3) Incomplete bladder emptying (neurogenic, voluntary)
4) Diabetes
5) Sickle cell
6) Immune compromise
7) Bladder instrumentation / foreign bodies
8) Congenital structural abnormalities
9) Sexual activity
10) Pregnancy
11) Catheterisation
* Incremental risk of CAUTI associated with each additional day of catheterisation.
What are 8 factors in the urinary tract host defenses?
- 8 factors in the urinary tract host defenses:
1) Urine - osmolality, pH
2) Sloughing of epithelial cells
3) Urine flow and micturition
4) Mucosal inhibitors of bacterial adherence
5) Complement activation
6) Inflammatory response
7) Immune responses
8) Commensals
What is the most common cause of community and hospital acquired UTIs?
What are 5 gram-negative bacteria that cause UTIs?
- The most common cause of community and hospital acquired UTIs is E.coli
- 5 gram-negative bacteria that cause UTIs:
1) Escherichia coli (E. coli)
2) Klebsiella sp.
3) Proteus mirabilis
4) Enterobacter sp.
5) Serratia sp
What are 2 different serotpyes of Uropathogenic E. coli (UPEC)?
What are 3 virulence factors of Uropathogenic E. coli (UPEC)?
- 2 different serotpyes of Uropathogenic E. coli (UPEC):
1) O (somatic)
* Antigen based on bacterial cell wall
2) K (capsular)
* Antigen based on capsule
- 3 virulence factors of Uropathogenic E. coli (UPEC):
1) Fimbriae (adhesion)
2) K antigen
3) Haemolysin
How can E.coli adhere to uroepithelial cells?
What are the 2 different types of fimbriae (pili)?
- E.coli can adhere to uroepithelial cells through fimbriae (pili)
- 2 different types of fimbriae (pili):
1) Type 1 fimbriae
2) Type P fimbriae
What 4 events can occur when bacteria adhere to uroepithelial cells?
- 4 events that can occur when bacteria adhere to uroepithelial cells:
1) Iron acquisition machinery activated via siderophores
2) Stimulates growth and reproduction
3) Once a monolayer has formed a biofilm may develop
4) Bacteria with type 1 fimbriae may become internalised in phagocytes and epithelial cells
What are 2 pathogenic factors of E.coli?
What type of structure are they?
How do they contribute to the virulence of E.coli?
- 2 pathogenic factors of E.coli:
1) K Antigen
* Polysaccharide
* Forms a micro-capsule
* Confers resistance to phagocytosis
2) Haemolysin
* Cytolytic exo-protein
* Damages tissue membranes in vivo
* Causes kidney damag
What type of bacteria is Proteus mirabilis?
What are 3 virulence factors of Proteus mirabilis?
- Proteus mirabilis is a Gram-negative bacillus
- It is a facultative anaerobe - an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent
- 3 virulence factors of Proteus mirabilis:
1) Peritrichous flagellae
* If a bacterium has a peritrichous arrangement of flagella, counterclockwise rotation of the flagella causes them to form a single bundle that propels the bacterium in long, straight or curved runs without a change in direction
2) Produces urease
* Bacterial urease splits urea and promotes the formation of ammonia and carbon dioxide leading to urine alkalinization and formation of phosphate salts
3) Swarming ability
* Rapid and coordinated multicellular migration of bacteria across a moist surface
What are 5 gram-positive bacteria that cause UTIs?
- 5 gram-positive bacteria that cause UTIs:
1) Staphylococcus saprophyticus
2) Staphylococcus epidermidis
3) Enterococcus sp.
4) Corynebacteria
5) Lactobacillus
What type of bacteria is Staphylococcus saprophyticus.
Where can Staphylococcus saprophyticus be found in the body?
What is it a common risk of?
What can increase the risk of UTIs from Staphylococcus saprophyticus?
- Staphylococcus saprophyticus is a gram-positive bacterium
- Staphylococcus saprophyticus is a coagulase-negative staphylococci (CoNS), which are a type of staph bacteria that commonly live on a person’s skin
- Staphylococcus saprophyticus is part of the normal microbiota of female perineum & vagina
- Staphylococcus saprophyticus is a common cause of community acquired UTIs and can cause symptomatic cystitis
- Sexual activity increases risk of UTIs from Staphylococcus saprophyticus