Flashcards in Session 7 - UTI Deck (59)
How are urine samples collected?
• Mid stream, as urethera's normal flora should not be collected
How can samples be collected from small children?
• Adhesive bag places over genitals
What is the issue with using an adhesive bag to collect urine from children?
• False positive rate of 20%
Where are catheter samples collected from?
• Needle placed up catheter tube
• Not from the bag
What is suprapubic aspiration of urine?
• Needle placed through suprapubic region of pelvis into bladder and urine aspirated up
How are collected samples stored between collection and culture?
• Transported at 4*C with a small amount of boric acid in collection tube
• Prevents bacterial division
• Prevents bacterial division
What investigations can be performed on cloudy urine?
• Turbidity test
• Dipstick testing
What is turbidity?
• Whether the urine looks cloudy - If so, indicative of UTI
What are four dipstick tests which can be performed on urine?
• Leukocyte esterase - Indicates presence of WBCs
• Nitrite - Indicates presence of nitrate reducing bacteria
• Haematuria - Present in UTI and many other conditions
• Proteinuria - Present in UTI and many other conditions
In what 6 situations is microscopy used on urine culture?
• Kidney disease
• Suspected endocarditis
• Children under 6
• Suprapubic aspirate
• When requested
What is urine culture and what needs to occur before infection can be confirmed?
• A number of colony forming units must occur - >100,00 per ml (10^5 cfu/ml) distinguished bacteriuria/contamination
What are the five main advantages of urine culture?
• To investigate complicated UTIs
• Gives epidemiology of isolates
• Sensitivity testing
• Specificity testing
• Control of specimen quality
○ Can differentiate between properly collected and contaminated samples (poorly collected samples may contain epithelial cells)
What 5 details are needed to correctly interpret a urine culture?
• Clinical details
○ Previous antibiotics
• Quality of specimen
• Delays in culture
• Organsims location
What is sterile pyuria?
Pus in urine
What does sterile pyuria indicate?
• A UTI is present but unable to be cultured
Give three situations where sterile pyuria would be present?
• Patient already treated with antibiotics
• OR infected with bacteria that are difficult isolate or culture
OR can be due to tuberculosis or appendicitis (appendix stuck on bladder
What are three other causes of UTI symptoms
• Vaginal infection/inflammation
• Sexually transmitted pathogens
• Mechanical/physical/chemical causes
What are general treatments for UTI?
• Increase fluid intake
• Address underlying disorders
How is an uncomplicated UTI treated?
• 3 day course of antibiotics
• 3 day course reduces the selection pressure for resistance
What is given for complicated UTI treatment?
5 day course antibiotics
Should amoxicillin be used to treat complicated UTI's?
50% of isolates (bacteria) resistance
How should pyelonephritis/septicaemia be treated?
• 14 day course of antibiotics
• Use more potent agent with systemic activity
When is antibiotic prophylaxis indicated?
• Three or more episodes of UTI in one year
No treatable underlying condition
What is antibiotic prophylaxis
• Single, low, nightly dose of antibiotics to prevent bacteria build up in static urine
• All breakthrough infections documented
What is pyelonephritis?
• Infection in kidney
What is the worst case scenario in a UTI?
• Bacteria manage to invade blood stream from urinary tract
• Gram negative septicaemia will occur
What are you likely to see in a culture of contaminated urine?
• Simple Squamous Epithelial cells
What is sensitivity of a test?
The rate of true positives