Urinary Tract Infections Flashcards
What is micturition?
Urination
What is cystitis?
Infection confined to the bladder
What is pyelonephritis?
Kidney infection
What is urethritis?
Inflammation of the urethra
What is prostatitis?
Inflammation of the prostate
What percentage of women have more than 1 UTI in their lifetime?
20 - 30%
What age are men who usually get UTIs?
> 50 years
How often are UTIs single or isolated attacks?
90%
What can recurrent attacks (10%) be due to?
- Relapse (20%)
Being infected with another pathogen - Reinfection (80%)
Being reinfected with the same infection
What are the signs/symptoms of a lower UTI infection?
- Frequency of micturition
- Urgency to urinate
- Dysuria
- Suprapubic pain + tenderness
- Smelly/cloudy urine
What are the signs/symptoms of an infection of pelvis and kidney (acute pyelonephritis)?
- Loin pain and kenderness
- High fever
- Systemic upset
What investigation should you perform if their are complications with a UTI?
Excretion urography
CT urogram
What can result in an abnormal Excretion urogram CT urogram?
- Stones
- Obstruction
- Polycystic kidneys
- Vesicoureteric reflux
What associated diseases can cause complications with UTIs?
- Diabetes Melitus
- Sickle cell disease
- Analgesic abuse
What is the Vesicoureteric reflux?
Condition in which urine flows retrograde, or backward, from the bladder into the ureters/kidneys.
How do E.coli adhere to the bladder?
P. fimbriae adhere to the uroepithelium
What is the most common cause of UTIs?
E. coli (80% of community acquired)
What are the 2 different serotypes of UPEC E. coli?
- O (somatic)
- K (capsular)
What are the virulence factors of E. coli?
- Fimbriae (adhesion)
- K antigen
- Haemolysin
What are the 2 different types of fimbriae (pili) on E. coli?
- Type 1
- Type P
What is iron acquisition machinary on E. coli activated via?
Siderophores
What is the response of E.coli to adhesion?
- Iron acquisition machinery activated via siderphores
- 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
What are the features of the E. coli K antigen?
- Polysaccharide
- Forms a micro-capsule
- Confers resistance to phagocytosis
What are the features of the E. coli Haemolysin?
- Cytolytic exo-protein
- Damages tissue membranes in vivo
- Causes kidney damage
What are some of the main features of Proteus Mirabilis?
- Gram negative
- Faculative anaerobe
- Bacillus
- Peritrichous flagellae
- Produces urease
- Swarming ability (produce surfactant)
What does urease produced by proteus mirabilis do?
- Breaks down urea into ammonia making urine less acidic and more alkali
- Can creat crystals of calcium carbonate which build up and creat kidney stones
What are the gram negative bacteria which can cause UTIs?
- Escherichia coli
- Proteus mirabilis
- Klebsiella sp.
- Enterobacter sp.
- Serratia sp.
What are some of the gram positive bacteria which can cause UTIs?
- Staphylococcus saprophyticus
- Staphylococcus epidermidis
- Enterococcus sp.
- Corynebacteria
- Lactobacillus
Where can staphylococcus saprophyticus be found normally?
Female perineum and vagina
WHat can increase the risk of staphylococcus saprophyticus?
Sexual activity
What are the features of staphylococcus saprophyticus?
- Gram positive
- Coagulase negative
What can be the non-bacterial causes of UTIs?
- Candida albicans
- Trichomonas vaginalis
- Schistosoma haematobium
- Mycobacterium fortuitum
- Histoplasma capsulatam
- Polyomaviruses
- CMV
- Rubella
When can a candida infection become serious?
- Opportunistic infection in immunocompromised individuals (can be deadly in HIV)
- Usually commensal
- Often associated with antibiotic use
What is Trichomonas vaginalis?
- Protozoa which can cause UTIs
- Pear-shaped flagellate
- Causes trichomoniasis
What is the pH at which trichomonas vaginalis prefers?
~6
What kind of worm is Schistosoma haematobium?
Trematode worm
What is schistosomiasis treated with?
Praziquantal
Where can the entry points be for bacteria entering a catheter?
- Urethral meatus and aroun catheter
- Junction between catheter and collection tube
- Connetion to drainage bag and reflux from bag to tubing
What is the bacteria content which deems urine to have significant bacteriuria?
- Mid stream specimen with >10^5 per ml
- Catheter specimen of urine will have lower number than MSU
When is a suprapubic aspiration of bladder urine taken?
- Very rare occasions
- Can be for schistosoma haematobium
What can bacteria cause nitrates to become?
Reduce to nitrites
What can leukocytes produce which appear on a dipstick?
Leukocyte esterase
What are the Urinary Tract host defenses?
- Urine - osmolality, pH
- Sloughing of epithelial cells
- Urine flow and micturition
- Mucosal inhibitors of bacterial adherence
- Complement activation
- Inflmmatory response
- Immune responses
- Commensals
What can cranberry/blueberry juice contain which can prevent UTIs?
Proanthrocyanidins
- Prevent E. coli from adhereing to the uroepithelium
What oral antibiotics can be used to treat UTIs?
- Co-trimoxazole
- Nitrofurantoin
- Nalidixic acid
- Co-amoxiclav
- Trimethoprim
- Ciprofloxacin
