Urinary Tract Infections Flashcards
Micturition
urination
Dysuria
pain on urination
Bacteriuria
presence of bacteria in urine
Haematuria
presence of blood in urine
Pyelonephritis
Kidney infection
Cystitis
infection confined to the bladder
Urethritis
inflammation of the urethra
Protastitis
prostate infection
Lower UTI: Signs and symptoms
- Frequency of micturition
- Urgency to urinate
- Dysuria
- Suprapubic pain and tenderness
- Haematuria
- Smelly/cloudy urine
Acute Pyelonephritis: Signs and Symptoms
- Loin pain and tenderness
- High fever
- Systematically unwell
UTI Predisposing Factors
- Obstruction: calculi, tumours, benign prostate hyperplasia
- Vesicoureteral Reflux (VUR)
- Incomplete bladder emptying (neurogenic, voluntary)
- Diabetes / Sickle Cell Anaemia / Immune Compromise
- Bladder instrumentation / Foreign bodies
- Congenital Structural Abnormalities
- Sexual activity
Catheter Associated UTI
- Each additional day of catheterisation increases the risk
- Entry Points for bacteria: urethral meatus and around catheter, junction between catheter and collection tube, connection to drainage bad and reflux from bag to tubing.
Urinary Tract Host Defenses
- Urine: osmolality, pH
- Sloughing of epithelial cells
- Urine flow and micturition
- Mucosal inhibitors of bacterial adherence
- Complement activation
- Inflammatory Response
- Immune Responses
- Commensals
Common Causes of UTIs
- E.Coli (80% of community-acquired; 40% of hospital acquired).
- Coagulase-Negative Staphylococci (10%;3%)
- Proteus Mirabilis (5%; 11%)
- Candida (5% of hospital acquired)
- Gram positives e.g. staphylococcus epidermis, staphylococcus aureus, enterococcus faecalis (2%; 16%)
- Gram negatives e.g. Klebsiella, Enterobacter, Serratia, Psuedomonas Aeruginosa (3%; 25%)
Uropathogenic E.Coli (UPEC)
- Certain serogroups of O and K serotypes
- O (somatic)
- K (capsular) - Virulence Factors
- Fimbriae (adhesions; type 1 and type P)
- K antigen
- Haemolysin
Bacterial Response 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.
E. Coli K-Antigen
Polysaccharide
Forms a micro-capsule
Confers resistance to phagocytosis
E.Coli Haemolysin
Cytolytic Exo-protein
Damages tissue membranes in vivo
Causes kidney damage
Proteus Mirabilis
- Gram negative
- Facultative Anaerobe
- Bacillus
- Peritrichous flagellae
- Produces urease
- Swarming ability
Gram Negative Bacteria
- Escherichia Coli
- Klebsiella sp.
- Proteus Mirabilis
- Enterobacter sp.
- Serratia sp.
Gram Positive Bacteria
- Staphylococcus Saprophyticus
- Staphylococcus Epidermidis
- Enterococcus sp.
- Corynebacteria
- Lactobacillus
Staphylococcus Saprophyticus
- Gram positive
- Coagulase negative
- Normal microbiota of female perineum and vagina
- Sexual activity increases risk of UTI
- Commonly causes community acquired UTIs
- Symptomatic Cystitis
Candidia Albicans
- Diploid fungus (yeast)
- Commensal
- Candidiasis (thrush)
- Important opportunistic pathogen in immunocompromised individuals
- Often associated with antibiotic use
Trichomonas Vaginalis
- Protozoan
- Pear shaped flagellate
- T. vaginalis is pathogenic
- Other species are commensal
- Prefers pH ~6
- Trichomoniasis
- Less common in males
Schistosoma Haematobium
- Trematode worm
- Schistomiasis (bilharzia)
- Found in contaminated water
- Gains access to host through skin
- Matures in liver
- Eggs travel to and penetrate bladder
- Treatment with Praziquantal
UTI Diagnosis
- Clinical Diagnosis - primarily based on signs and systems. Women who present with acute UTI signs and symptoms but are otherwise healthy have an 80% chance of bacteriuria. If dysuria and frequency are also present, probability is increased to over 90% and empirical treatment with antibiotics is indicated without further testing.
- Urine Dipstick - only use for women under 65 with no risk factors for a complicated UTI or children between 3 months and 16 years to help diagnose.
- Urine Culture - Indicated in children, male UTI, immunosuppressed, pregnancy, toxic appearance, underlying medical/urologic disorder, recently hospitalised, recently instrumented, recently on antibiotics, recent treatment failure.
Oral antibiotics for Lower UTIs
- Nitrofurantoin
- Trimethoprim
- Ciprofloxacin
- Pivmecillinam
- Amoxicillin/Cephalexin (pregnancy)
Oral Antibiotics for Pyelonephritis
- Co-trimoxazole
- Co-amoxiclav
- Ciprofloxacin
Treatments for UTIs
- Drink lots of water
- Dont hold it in
- Proanthrocyanidins (cranberry juice)
Complications of UTIs
- Recurrent infections
- Permanent kidney damage from an acute or chronic kidney infection
- Pyelonephritis due to an untreated UTI
- Increased risk of pregnant women of delivering low birth weight ir premature infants.
- Urethral narrowing (stricture) in men from recurrent urethritis, previously seen with gonococcal urethritis.
- Sepsis, a potentially life-threatening complication of an infection.
