UTIs Flashcards by sami sh

Do UTIs affect men or women more ?

• More common in women than men

20-30% women have ≥1 UTI in lifetime

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Describe the time frame of UTIs.

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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What are the signs and symptoms of lower UTIs ?

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

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

– Loin pain and tenderness
– High fever
– Systemic upset

Acute pyelonephritis

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Identify possible complications of UTIs.

Stones
Obstruction
Polycystic kidney
Vesicoureteric reflux

Overall, risk of kidney damage and septiciemia

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Identify possible diseases associated with complications from UTIs.

Diabetes Mellitus
Sickle Cell
Analgesic Abuse

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Identify factors favoring UTIs.

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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Identify the main pathogens responsible for UTIs.

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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Identify the main gram negative bacteria responsible for UTIs.

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

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Which type of E. Coli causes UTIs ?

Uropathogenic E. coli (UPEC)

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What are the main serotypes of E Coli ?

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

K (capsular) - K antigens are in capsule

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

– Fimbriae (adhesion)
– K antigen
– Haemolysin

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

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

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

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

Polysaccharide

- Forms a microcapsule, so confers resistance to phagocytosis

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

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Cytolytic exo-protein

* Damages tissue membranes in vivo, and causes kidney damage

State the main classifications of Proteus Mirabilis.

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Gram negative
Facultative anaerobe
Bacillus

Identify the main virulence factors of Proteus Mirabilis.

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Peritrichous flagellae
Produces urease
Swarming ability

Identify the main gram positive bacteria responsible for UTIs.

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Staphylococcus saprophyticus
Staphylococcus epidermidis
Enterococcus sp.

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

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More responsible for nosocomially acquired infections

State the main classifications of Staph. saprophyticus.

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Gram positive
Coagulase negative
Normal microbiota of female perineum and vagina

What UTI infection does Staph. saprophyticus usually cause ?

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Symptomatic cystitis

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

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

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

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Candidia albicans
Trichomonas vaginalis
Schistosoma haematobium

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.

What kind of pathogen is Trichomonas Vaginalis ? What infections does it cause ?

* Protozoan * Pear-shaped flagellate * Pathogenic (other species are commensal) Causes trichomoniasis.

What pH does Trichomonas Vaginalis prefer ?

• Prefers pH ~6.0

Describe the epidemiology of Trichomonas vaginalis infections.

Less common in males

What kind of pathogen is Schistosoma haematobium ?What infection does it cause ,

• Trematode worm Causes Schistosomiasis (bilharzia).

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

What is the treatment for Schistosoma haematobium infections ?

• Treatment with praziquantal

Identify the main entry points for bacteria in catheterisation.

- Urethral meatus and around catheter | - Connection to drainage bag and reflux from bag to tubing

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.)

What kind of testing may be required in UTI ?

- Urine specimens for lab analysis | - Urine dipstick test

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)

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.

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)

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

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

UTIs Flashcards

(39 cards)