UTIs Flashcards

1
Q

Do UTIs affect men or women more ?

A

• More common in women than men

20-30% women have ≥1 UTI in lifetime

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2
Q

Describe the time frame of UTIs.

A

Usually acute and short lived (90%)

In a minority of cases (10%), they are recurrent, in which case they may either be relapses (20%) or reinfections (80%)

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3
Q

What are the signs and symptoms of lower UTIs ?

A
– Frequency of micturition
– Urgency to urinate
– Dysuria
– Suprapubic pain and tenderness 
– Haematuria
– Smelly / cloudy urine
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4
Q

What are signs and symptoms of pelvis and kidney infection ? What is the name for such an infection ?

A

– Loin pain and tenderness
– High fever
– Systemic upset

Acute pyelonephritis

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5
Q

Identify possible complications of UTIs.

A

Stones
Obstruction
Polycystic kidney
Vesicoureteric reflux

Overall, risk of kidney damage and septiciemia

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6
Q

Identify possible diseases associated with complications from UTIs.

A

Diabetes Mellitus
Sickle Cell
Analgesic Abuse

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7
Q

Identify factors favoring UTIs.

A

Bacterial attributes:

  • Urease
  • Haemolysins
  • Adhesion in uroepithelium (P. fimbriae in E. Coli)
  • Capsular antigens

Host factors:

  • Renal calculi
  • Ureteric reflux
  • Tumors in and adjacent to UT
  • Pregnancy
  • Bladder stones
  • Catheterisation
  • Short urethra in women
  • Prostatic hypertrophy
  • Neurologic problems (incomplete bladder emptying, large V of residual urine, loss of sphincter control)
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8
Q

Identify the main pathogens responsible for UTIs.

A

Community acquired:

  • E-coli
  • Coagulase negative staph

Hospital (nosocomially) acquired:

  • E-coli
  • Proteus Mirabilis
  • Other gram negatives (Klebsiella Enterobacter, Pseudomonas Aeruginosa)
  • Other gram positives (Staph epidermidis, Staph aureus)
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9
Q

Identify the main gram negative bacteria responsible for UTIs.

A
  • Escherichia coli (both community acquired and nosocomial)
  • Proteus mirabilis (esp. nosocomial infections)
  • Klebsiella sp.
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10
Q

Which type of E. Coli causes UTIs ?

A

Uropathogenic E. coli (UPEC)

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11
Q

What are the main serotypes of E Coli ?

A

O (somatic) - O antigens are found in bacterial cell wall

K (capsular) - K antigens are in capsule

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12
Q

Identify the main virulence factors for E. Coli in UTIs.

A

– Fimbriae (adhesion)
– K antigen
– Haemolysin

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13
Q

Describe how and where E. coli adheres, in UTIs.

A

-Specific adhesion to uroepithelial cells
-Through fimbriae (pili), two types:
Type 1 fimbriae
Type 2 fimbriae

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14
Q

What are the bacterial responses of E. coli to adhesion ?

A
  • Iron acquisition machinery activated via siderophores
  • Stimulates growth and reproduction
  • Once a monolayer has formed a biofilm may develop
  • Bacteria with type 1 fimbriae may become internalised in phagocytes and epithelial cells
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15
Q

What kind of molecule is K antigen ? Describe the advantages conferred by the K antigen, to E. coli in UTIs.

A
  • Polysaccharide

- Forms a microcapsule, so confers resistance to phagocytosis

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16
Q

What kind of molecule is haemolysin ? Describe the advantages conferred by Haemolysin, to E. coli in UTIs.

A
  • Cytolytic exo-protein

* Damages tissue membranes in vivo, and causes kidney damage

17
Q

State the main classifications of Proteus Mirabilis.

A
  • Gram negative
  • Facultative anaerobe
  • Bacillus
18
Q

Identify the main virulence factors of Proteus Mirabilis.

A
  • Peritrichous flagellae
  • Produces urease
  • Swarming ability
19
Q

Identify the main gram positive bacteria responsible for UTIs.

A
  • Staphylococcus saprophyticus
  • Staphylococcus epidermidis
  • Enterococcus sp.
20
Q

Are gram positive bacteria more responsible for community acquired or nosocomially acquired infections ?

A

More responsible for nosocomially acquired infections

21
Q

State the main classifications of Staph. saprophyticus.

A
  • Gram positive
  • Coagulase negative
  • Normal microbiota of female perineum and vagina
22
Q

What UTI infection does Staph. saprophyticus usually cause ?

A

Symptomatic cystitis

23
Q

What is a prediposing factor to UTI due to Staphylococcus saprophyticus ?

A

• Sexual activity increases risk of UTI due to Staphylococcus saprophyticus (commonly causes community acquired UTIs)

24
Q

Identify other pathogens (other than bacteria) associated with UTIs.

A
  • Candidia albicans
  • Trichomonas vaginalis
  • Schistosoma haematobium
25
What kind of pathogen is Candida Albicans ? What infections does it cause ?
* Diploid fungus (yeast) * Commensal (so not pathogenic straight away) Causes candidiasis (thrush). Especially in immunocompromised individuals (opportunistic pathogen), and often associated with antibiotic use.
26
What kind of pathogen is Trichomonas Vaginalis ? What infections does it cause ?
* Protozoan * Pear-shaped flagellate * Pathogenic (other species are commensal) Causes trichomoniasis.
27
What pH does Trichomonas Vaginalis prefer ?
• Prefers pH ~6.0
28
Describe the epidemiology of Trichomonas vaginalis infections.
Less common in males
29
What kind of pathogen is Schistosoma haematobium ?What infection does it cause ,
• Trematode worm Causes Schistosomiasis (bilharzia).
30
How is Schistosoma haematobium transmitted ? Briefly describe its life cycle.
* Found in contaminated water, and gains access to host through skin * Matures in liver + eggs travel to and penetrate bladder
31
What is the treatment for Schistosoma haematobium infections ?
• Treatment with praziquantal
32
Identify the main entry points for bacteria in catheterisation.
- Urethral meatus and around catheter | - Connection to drainage bag and reflux from bag to tubing
33
Why is catheterisation associated with a higher risk of UTI ?
Because 1) Gives pathogens surface to form biofilm 2) Disrupts normal protective functions of urinary system (flushing etc.)
34
What kind of testing may be required in UTI ?
- Urine specimens for lab analysis | - Urine dipstick test
35
Identify the main urine specimens for lab analysis which may be required in UTIs, and identify the main feature of each.
1) MSU–mid-stream specimen of urine (significant bacteriuria, >10^5 per ml) 2) CSU – catheter specimen of urine (significant bacteriuria, lower number of micro-organisms than MSU) 3) Suprapubic aspiration of bladder urine (for Schistosoma haematobium and other rare occasions)
36
In a mid-stream specimen of urine, how many strains of pathogens should be found ?
If infection, only one. | If more than one, means it's been contaminated.
37
What features of the urine dipstick test would point to a UTI ?
(Bright color and very foul smell in appearance) - Nitrates reduced into nitrites (so increased nitrites) - Increased leukocytes (also, leukocytes produced esterases, but that isn't shown by test)
38
Identify the main host defenses of the urinary tract.
* Urine - osmolality, pH * Sloughing of epithelial cells * Urine flow and micturition * Mucosal inhibitors of bacterial adherence * Complement activation * Inflammatory response * Immune responses * Commensals
39
Identify oral antibiotics used for UTIs.
* Co-trimoxazole (first line therapy, go-to drug) * Nitrofurantoin (go-to drug for E. coli and staph) * Nalidixic acid * Co-amoxiclav * Trimethoprim * Ciprofloxacin Also, drink plenty of water