22-02-23 – Urinary Tract Infections Flashcards

1
Q

Learning outcomes

A
  • 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
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2
Q

Definitions
* Micturition
* Dysuria
* Bacteriuria
* Haematuria
* Pyelonephritis
* Cystitis
* Urethritis
* Prostatitis

A
  • 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
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3
Q

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?

A
  • 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
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4
Q

What % of UTIs are single are isolated attacks?

What % of UTIs are recurrent attacks?

A
  • 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

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5
Q

What are 6 signs and symptoms of Lower UTIs?

What are 3 signs and symptoms of Infections of pelvis and kidney (acute pyelonephritis)?

A
  • 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
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6
Q

What are 11 predisposing factors for UTIs?

A
  • 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.

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7
Q

What are 8 factors in the urinary tract host defenses?

A
  • 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  
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8
Q

What is the most common cause of community and hospital acquired UTIs?

What are 5 gram-negative bacteria that cause UTIs?

A
  • 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
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9
Q

What are 2 different serotpyes of Uropathogenic E. coli (UPEC)?

What are 3 virulence factors of Uropathogenic E. coli (UPEC)?

A
  • 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
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10
Q

How can E.coli adhere to uroepithelial cells?

What are the 2 different types of fimbriae (pili)?

A
  • E.coli can adhere to uroepithelial cells through fimbriae (pili)
  • 2 different types of fimbriae (pili):
    1) Type 1 fimbriae
    2) Type P fimbriae
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11
Q

What 4 events can occur when bacteria adhere to uroepithelial cells?

A
  • 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

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12
Q

What are 2 pathogenic factors of E.coli?

What type of structure are they?

How do they contribute to the virulence of E.coli?

A
  • 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

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13
Q

What type of bacteria is Proteus mirabilis?

What are 3 virulence factors of Proteus mirabilis?

A
  • 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

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14
Q

What are 5 gram-positive bacteria that cause UTIs?

A
  • 5 gram-positive bacteria that cause UTIs:
    1) Staphylococcus saprophyticus
    2) Staphylococcus epidermidis
    3) Enterococcus sp.
    4) Corynebacteria
    5) Lactobacillus
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15
Q

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?

A
  • 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
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16
Q

What are 8 other microorganisms that can cause UTIs?

A
  • 8 other microorganisms that can cause UTIs:
    1) Candidia albicans
    2) Trichomonas vaginalis
    3) Schistosoma haematobium
    4) Mycobacterium fortuitum
    5) Histoplasma capsulatum
    6) Polyomaviruses
    7) CMV
    8) Rubella
17
Q

What kind of microorganism is Candida albicans?

What role does Candida albicans play in the body?

What condition can Candida albicans cause?

What groups is Candida albicans an opportunistic pathogen in?

What is it often associated with?

A
  • Candida albicans is a Diploid fungus (yeast)
  • Candida albicans is a commensal organism
  • Candida albicans can cause Candidiasis (thrush)
  • Candida albicans is an important opportunistic pathogen in immunocompromised individuals
  • It is often associated with antibiotic use
18
Q

What type of microorganism is Trichomonas vaginalis?

Is it commensal, symbiotic or pathogenic?

What pH does it prefer?

What condition does it cause? What sex is it more common in?

A
  • Trichomonas vaginalis is a protozoan and a pear-shaped flagellate
  • Trichomonas vaginalis is pathogenic, while other species are commensal
  • It Prefers pH ~6.0
  • Trichomonas vaginalis causes Trichomoniasis
  • It is more common in females
19
Q

What type of microorganism is Schistosoma haematobium?

What can it cause?

Where is Schistosoma haematobium found?

How does it gain access to the host?

Where does it mature?

Where can its eggs penetrate?

How is Schistosoma haematobium treated?

A
  • Schistosoma haematobium is a Trematode worm
  • It can cause Schistosomiasis (bilharzia)
  • Schistosoma haematobium is found in contaminated water
  • It gains access to host through skin
  • It matures in liver and its eggs travel to and penetrate bladder
  • Schistosoma haematobium is treated with praziquantel
20
Q

What are 3 ways UTIs can be diagnosed?

A
  • 3 ways UTIs can be diagnosed:
    1) Clinical
    2) Urine dipstick
    3) Laboratory diagnosis
21
Q

How are UTIs primarily diagnosed?

How common is bacteriuria women that present with symptoms of acute UTI?

What does the probability rise to when dysuria and frequency are both present?

What is indicated in this case?

A
  • The diagnosis of UTI is primarily based on symptoms and signs
  • The probability of bacteriuria in otherwise healthy women who present to their general practitioner (GP) with symptoms of acute UTI is estimated at between 50- 80%.
  • If dysuria and frequency are both present, then the probability of UTI is increased to >90% and empirical treatment with antibiotic is indicated, with no need for further testing.
22
Q

Why do we use urine dipstick when testing for UTIs?

What substances are we mainly looking for?

What other substances may be present?

A
  • We use urine dipstick when testing for UTIs as it serves as an indirect marker of inflammatory response in the host
  • The main thing we are looking for is nitrites
  • We may also see blood or leukocytes and other inflammatory cells
23
Q

In what 2 scenarios would we use urine dipstick to test for UTIs?

In what 3 scenarios would we not use urine dipstick to test for UTIs?

A
  • 2 scenarios we would use urine dipstick to test for UTIs:

1) If the woman is under 65 years of age, and does not have risk factors for complicated UTI, urine dipstick can be used as an aid to diagnosis

2) Children 3 months – 16 years old, as they cant verbalise as well

  • 3 scenarios would we not use urine dipstick to test for UTIs:

1) Do not use urine dipstick tests or microscopy to diagnose UTI in men — dipsticks are poor at ruling out infection

2) Dipstick becomes more unreliable in patients over 65 years old

3) Do not use dipstick test for diagnosing UTI in older people or people with indwelling catheters

24
Q

Scottish Antimicrobial Prescribing Group (SAPG) Guidelines for diagnosing UTI in older people

A
25
Q

What are 10 indications for urine culture when testing for UTIs?

Why is urine culture advantageous?

A
  • 10 indications for urine culture when testing for UTIs:
    1) Children
    2) Male UTI
    3) Immunosuppressed
    4) Pregnancy
    5) Toxic appearance
    6) Underlying medical / urologic disorder
    7) Recently hospitalized
    8) Recently instrumented
    9) Recently on antibiotics
    10) Recent treatment failure
  • Urine culture is advantageous as it can tell is which antibiotics can work
26
Q

What are 5 oral anti-biotics for Lower UTIs?

What are 3 oral antibiotics for Pyelonephritis?

What is another way UTIs can be treated?

A
  • 5 oral anti-biotics for Lower UTIs:
    1) Nitrofurantoin (first line)
    2) Trimethoprim (first line)
    3) Ciprofloxacin
    4) Pivmecillinam
    5) Amoxicillin / cephalexin (pregnancy)
  • 3 oral antibiotics for Pyelonephritis (usually broad spectrum):
    1) Co-trimoxazole
    2) Co-amoxiclav
    3) Ciprofloxacin
  • UTIs can also be treated by drinking plenty of water
27
Q

What are 6 complications of UTIs?

A
  • 6 complications of UTIs:

1) Recurrent infections

2) Permanent kidney damage from an acute or chronic kidney infection

3) Pyelonephritis due to an untreated UTI.

4) Increased risk in pregnant women of delivering low birth weight or premature infants.

5) Urethral narrowing (stricture) in men from recurrent urethritis, previously seen with gonococcal urethritis.

6) Sepsis, a potentially life-threatening complication of an infection

28
Q

What are 4 ways to treat recurrent UTIs?

A
  • 4 ways to treat recurrent UTIs:

1) Personal hygiene measures and self-care

2) Vaginal oestrogen for postmenopausal women

3) Antibiotic prophylaxis – choice and dose dependant on age. – When exposed to a trigger – Daily dose

4) Methenamine Hippurate (an antiseptic)