Urinary Tract Infection Flashcards
Urinary tract infections (UTIs) refer to an infection of any part of the urinary system from .. to the ..
Urinary tract infections (UTIs) refer to an infection of any part of the urinary system from kidney to the urethra.
UTIs are generally defined as the presence of characteristic symptoms (e.g. dysuria, frequency) and significant bacteriuria (presence of bacteria in urine). Significant bacteriuria is defined as > … colony forming units (CFU)/ml. In the absence of symptoms, this level of bacteriuria is termed asymptomatic bacteriuria.
UTIs are generally defined as the presence of characteristic symptoms (e.g. dysuria, frequency) and significant bacteriuria (presence of bacteria in urine). Significant bacteriuria is defined as > 10^5 colony forming units (CFU)/ml. In the absence of symptoms, this level of bacteriuria is termed asymptomatic bacteriuria.
UTIs can be further categorised depending on the location of infection (e.g. upper or lower) or the presence of co-morbidities (e.g. complicated or uncomplicated).
Upper UTI: infection of the kidney (pyelonephritis)
Lower UTI: infection of the bladder (cystitis) and urethra (urethritis)
Uncomplicated UTI: if occurring in healthy non-pregnant adult women
Complicated UTI: the presence of factors that increase the risk of treatment failure (e.g diabetes, structural abnormalities, catheter and other devices and all UTIs in men)
UTIs occurring in men are generally considered ‘…’ as many occur in children and the elderly in association with urological abnormalities, malignancy or immunosuppression.
UTIs occurring in men are generally considered ‘complicated’ as many occur in children and the elderly in association with urological abnormalities, malignancy or immunosuppression.
UTIs are caused by the organism… in 75-90% of cases.
UTIs are caused by the organism Escherichia coli in 75-90% of cases.
Gram negative bacillus
Escherichia coli (E. coli) is a … bacillus that is a facultative inhabitant of the large intestines. E. coli may cause a wide range of infections including, respiratory infections, intra-abdominal infections, enteric infections and urinary infections.
Uropathogenic strains of E. coli infect the urinary tract leading to a wide range of problems including urethritis, prostatitis, cystitis, pyelonephritis and urosepsis.
Escherichia coli (E. coli) is a gram-negative bacillus that is a facultative inhabitant of the large intestines. E. coli may cause a wide range of infections including, respiratory infections, intra-abdominal infections, enteric infections and urinary infections.
Uropathogenic strains of E. coli infect the urinary tract leading to a wide range of problems including urethritis, prostatitis, cystitis, pyelonephritis and urosepsis.
Other common microorganisms associated with UTIs include: (aside from E.coli)
Proteus mirabilis
Klebsiella pneumoniae
Staphylococcus saprophyticus
A growing number of UTIs are secondary to … (ESBL) producing E. coli.
A growing number of UTIs are secondary to extended-spectrum beta-lactamase (ESBL) producing E. coli.
ESBL
A growing number of UTIs are secondary to extended-spectrum beta-lactamase (ESBL) producing E. coli.
What are they highly resistant to?
These organisms are highly resistant to most beta-lactam antibiotics, which includes penicillins and cephalosporins. Beta-lactamases are enzymes which open the beta-lactam ring of beta-lactam antibiotics rendering them inactive.
ESBL infections are a growing cause of hospital-acquired infections associated with poor outcomes. The risk of developing ESBL infections is linked to the prior administration of antibiotics, the length of ITU stay and the presence of a urinary catheter, among others. Treatment often requires …
ESBL infections are a growing cause of hospital-acquired infections associated with poor outcomes. The risk of developing ESBL infections is linked to the prior administration of antibiotics, the length of ITU stay and the presence of a urinary catheter, among others. Treatment often requires potent, broad-spectrum antibiotics (e.g. Carbapenems).
Pathophysiology of UTI - overview
The normal urinary tract is a sterile environment.
The development of UTIs results from colonisation and ascending spread of microorganisms from the urethra into the bladder (lower) and kidney (upper), or by haematogenous spread via the blood. Many pathogens have adaptions that allow them to breach host defences.
Microorganism spread - UTI
In women, infections start with the colonisation of the vaginal introitus (entrance to the vaginal canal) and periurethral area. It then ascends the urethra to cause infection of the bladder. Infections are uncommon in men for a number of reasons. They have a longer urethra, prostatic secretions have some antimicrobial properties and their periurethral area is generally drier.
Why are UTIs less common in men?
Infections are uncommon in men for a number of reasons. They have a longer urethra, prostatic secretions have some antimicrobial properties and their periurethral area is generally drier.
UTIs may also develop from the haematogenous spread of microorganisms. However, common gram-negative bacilli (e.g. E. coli) are unlikely to cause infection by this route. Haematogenous spread is more often seen with uncommon urinary microorganisms such as …
UTIs may also develop from the haematogenous spread of microorganisms. However, common gram-negative bacilli (e.g. E. coli) are unlikely to cause infection by this route. Haematogenous spread is more often seen with uncommon urinary microorganisms such as Staphylococcus aureus, Candida albicans and Mycobacterium tuberculosis.
Host and pathogen - UTI
The ability of microorganisms to infect the urinary system is dependent on both the host and pathogen. Host factors such as intercurrent illness, immunosuppression (e.g. steroid use) or co-morbidities (e.g. diabetes) can increase the risk of developing a UTI.
Some pathogens are particularly well suited to infecting the urinary tract. For example, uropathogenic strains of E. coli contain fimbriae, these are hair-like protein polymers that project from the bacterial surface. They allow strong adherence to the urothelium. Fimbriae play a crucial role in the pathogenesis of UTIs and have been shown to increase bacterial survival.
Risk factors for UTI
UTIs are extremely common especially among young, sexually active females.
Risk factors for the development of UTIs include:
Recent sexual intercourse Diabetes History of UTIs Spermicide use Catheters
… are one of the major risk factors for developing a UTI in secondary care.
Urinary catheters are one of the major risk factors for developing a UTI in secondary care. UTIs associated with catheters are a leading cause of hospital-associated bacteraemia.
Typical clinical features of UTIs include (2)
Typical clinical features of UTIs include dysuria (often described as burning) and increased frequency.
Symptoms in UTI
Dysuria Frequency Urgency Incontinence Suprapubic pain Haematuria N&V
Dysuria is commonly described, women who suffer with recurrent UTIs will often identify the symptoms early. Clinicians should be alert for signs of … which include kidney pain, myalgia, fevers, rigors and nausea/vomiting.
Dysuria is commonly described, women who suffer with recurrent UTIs will often identify the symptoms early. Clinicians should be alert for signs of pyelonephritis which include kidney pain, myalgia, fevers, rigors and nausea/vomiting.
Signs of UTI
Fever Rigors Flank pain Confusion Costovertebral angle tenderness
Signs and symptoms of…
UTI
Urosepsis - define
Urosepsis refers to a sepsis that originates from a urinary infection. Sepsis can be thought of as a dysregulated host response to infection leading to life-threatening organ dysfunction. Features include haemodynamic instability, tachypnea, changes to mental status, reduced urine ouput and pyrexia.
There are a number of scoring systems that can be used to assess risk and prognosis, each has their own limitations. An example is qSOFA (quick Sepsis Related Failure Assessment) that aims to identify patients at increased risk of poor outcomes outside the ITU environment. It consists of three components:
Mental status (score 1 if altered mental status) Respiratory rate (score 1 if ≥ 22) Systolic BP (score 1 if ≤ 100)
Mental status (score 1 if altered mental status) Respiratory rate (score 1 if ≥ 22) Systolic BP (score 1 if ≤ 100)
What scoring system is this?
qSOFA (quick Sepsis Related Failure Assessment)
aims to identify patients at increased risk of poor outcomes outside the ITU environment.
UTI - Patients with… should receive urgent review by a senior clinician and a MET/Peri-arrest call if indicated. All patients with significant infection should have a senior review.
haemodynamic instability, a lactate greater than 2 or evidence of end-organ dysfunction (or any other reason for concern)
Three In - sepsis 6 UTI
Patients should receive high flow oxygen to achieve appropriate target saturations. A target of 94-98% is appropriate for the majority of patients. Those at risk of carbon dioxide retention (COPD) should have a target of 88-92%. IV fluids should be started, often 500ml of crystalloid over 15 minutes with reference the patient’s haemodynamic status and co-morbidities. Antibiotics are key and should be given without delay, NICE recommend empirical treatment with piperacillin/tazobactam (tazocin).
Three out - sepsis 6 UTI
A minimum of two sets of blood cultures should be taken. Ideally, this should happen prior to administration of antibiotics though they should not be a cause for delay. A serum lactate should be obtained normally via a blood gas (arterial or venous) to help assess the patient’s status. Urine output should be measured ideally with a catheter with a careful fluid balance recorded.
The definitive diagnosis of a UTI is based on typical clinical features associated with positive laboratory evidence of …/…
The definitive diagnosis of a UTI is based on typical clinical features associated with positive laboratory evidence of pyuria +/- bacteriuria.
In young, non-pregnant females, typical clinical features (e.g. dysuria, suprapubic pain) in the absence of vaginal symptoms, is highly suggestive of a UTI. In this patient group, the probability of a UTI is > …%. Further laboratory testing offers little to the diagnosis, however as a minimum, the majority of clinicians would do a urine dip.
In young, non-pregnant females, typical clinical features (e.g. dysuria, suprapubic pain) in the absence of vaginal symptoms, is highly suggestive of a UTI. In this patient group, the probability of a UTI is > 90%. Further laboratory testing offers little to the diagnosis, however as a minimum, the majority of clinicians would do a urine dip.
In the presence of complicating factors (e.g. systemic upset, diabetes, pregnancy, recurrent UTIs), further laboratory testing is necessary. Urinalysis, involving a urine dipstick and urinary … is key
In the presence of complicating factors (e.g. systemic upset, diabetes, pregnancy, recurrent UTIs), further laboratory testing is necessary. Urinalysis, involving a urine dipstick and urinary microscopy, culture & sensitivity, (MC&S), is key.
A urine dipstick is useful to measure the presence of … and …
A urine dipstick is useful to measure the presence of leucocyte esterase (an enzymes released by WBCs, which reflects pyuria) and nitrites. The latter is because common urinary tract pathogens are able to convert nitrate into nitrite.
The presence of both leucocytes and nitrites is strongly associated with a UTI, however, the absence of one or both of these findings does not rule out a UTI if there is still a high clinical suspicion.
The presence of both … and … is strongly associated with a UTI, however, the absence of one or both of these findings does not rule out a UTI if there is still a high clinical suspicion.
The presence of both leucocytes and nitrites is strongly associated with a UTI, however, the absence of one or both of these findings does not rule out a UTI if there is still a high clinical suspicion.
Urinary MC&S
A urinary MC&S may identify the infecting microorganism and can help guide antibiotic sensitivities.
This is essential for patients with recurrent UTIs where resistance may have developed to previously used antibiotics.
Further investigations - UTI
Further testing involves the use of blood tests and radiological investigations. These may be warranted in those who do not respond to treatment, present with a severe infection, have an atypical infection or underlying co-morbidities.
A full blood count, urea & electrolytes and a CRP forms the basic screen of blood tests. They may show raised inflammatory markers and impaired renal function. The latter is particularly important to assess for the development of an acute kidney injury (AKI).
Radiological investigations are usually reserved for complicated pyelonephritis or uncomplicated UTIs that do not respond to conventional antibiotic therapy. It can include both ultrasonography and computed tomography. They are useful for the assessment of abscesses, haemorrhage, calculi, obstruction and emphysematous pyelonephritis.
Management of UTIs involves the prescription of appropriate antibiotic therapy according to local guidelines and concordance with any culture results.
The choice of antibiotic, route of administration and duration of therapy is dependent on multiple factors. These may include sex, severity, sensitivities, infecting organism and response to treatment. Some example regimes are shown below.
In those presenting with features of sepsis, a full assessment including sepsis six (and any other investigations indicated by review) and senior review should be sought.
Acute uncomplicated UTIs can generally be managed with antibiotics such … OR …
Acute uncomplicated UTIs can generally be managed with antibiotics such as trimethoprim or nitrofurantoin. The former should be avoided in pregnancy and the latter in renal impairment. A typical course of trimethoprim may be 200 mg BD for 3 days in women or 7-14 days in men. Nitrofurantoin is given at a dose of 50 mg QDS or 100 mg MR BD for 3 days in women or 7-14 days in men.
Acute uncomplicated pyelonephritis that does not require admission to hospital can be treated with a course of an oral fluoroquinolone such as 500 mg of ciprofloxacin 12-hourly for 14 days.
Acute uncomplicated pyelonephritis that does not require admission to hospital can be treated with a course of an oral … such as 500 mg of ciprofloxacin 12-hourly for 14 days.
Acute uncomplicated pyelonephritis that does not require admission to hospital can be treated with a course of an oral fluoroquinolone such as 500 mg of ciprofloxacin 12-hourly for 14 days.
Intravenous … (e.g. 1.2 g 8-hourly, adjusted based on renal function) or ceftriaxone may be used for patients with urosepsis or acute severe pyelonephritis.
Intravenous co-amoxiclav (e.g. 1.2 g 8-hourly, adjusted based on renal function) or ceftriaxone may be used for patients with urosepsis or acute severe pyelonephritis.
Acute complicated cystitis may be treated with an oral course of a …. In the presence of more severe disease (e.g. urosepsis) or patients unable to tolerate oral therapy, broad-spectrum IV antibiotics can be used.
Acute complicated cystitis may be treated with an oral course of a fluoroquinolone. In the presence of more severe disease (e.g. urosepsis) or patients unable to tolerate oral therapy, broad-spectrum IV antibiotics can be used.
Catheter-associated UTIs
A urinary catheter or other indwelling catheter (e.g. suprapubic) is a major risk factor for the development of a UTI.
A catheter-associated UTI is diagnosed in the presence of bacteriuria (> 103 CFU/ml) of a uropathogenic organism in the presence of clinical features suggestive of a UTI without another possible source of infection.
Asymptomatic bacteriuria is common in catheterised patients and as such the diagnosis should take the clinical picture into account.
Catheter-associated UTIs
What microorganisms typically cause these?
Microorganisms causing catheter-associated UTIs are similar to those causing normal UTIs (e.g. E. coli most common). However, other species such as Enterococcus, Candida, Pseudomonas and Klebsiella should also be considered.
Treatment involves the use of appropriate antibiotic therapy as with all UTIs. Ideally, an infected urinary catheter should be removed or changed under antibiotic coverage.
Define cystitis
Cystitis is inflammation of the bladder, usually caused by a bladder infection
Upper UTI - kidney and proximal ureter
Both = pyelonephritis
Just proximal ureter = pyelitis
E.coli - gram stain colour
red - gram negative
Staph aureus gram stain?
Violet blue
Clavulanate potassium is a potassium salt of clavulanic acid. Clavulanic acid is a beta-lactamase inhibitor.
Beta-lactamases are enzymes which open the beta-lactam ring of beta-lactam antibiotics (e.g. penicillins and cephalosporins) rendering them inactive. Clavulanic acid acts to prevent these enzymes taking effect.
What is the definition of a significant bacteriuria?
A > 100 colony forming units (CFU)/ml
B > 1,000 colony forming units (CFU)/ml
C > 10,000 colony forming units (CFU)/ml
D > 100,000 colony forming units (CFU)/ml
E > 1,000,000 colony forming units (CFU)/ml
A significant bacteriuria is defined as > 100,000 colony forming units (CFU)/ml
CFU is a measure of viable bacterial cells. A significant bacteriuria is highly indicative of UTI whilst lower levels may simply indicate contamination.
Approximately …% of patients with indicative symptoms and a nitrite positive dipstick will have a UTI.
Approximately 90% of patients with indicative symptoms and a nitrite positive dipstick will have a UTI.
Which immunoglobulin protects the bodies mucosal surfaces (including the urothelium)?
A IgA B IgD C IgE D IgG E IgM
IgA is found on the bodies various mucosal surfaces including the intestines, respiratory tracts, oral mucosa and urothelium.
It helps prevent attachment and invasion of the urothelium by pathogens.
Why do we need to worry about our antibiotic use in suspected UTI?
Rates of E. coli blood stream infections have increased by 24.3% from 2012-2016
Mandatory surveillance indicates the following risk factors
oprevious urinary tract infections (UTIs)
ourinary catheters
oantibiotics in the previous month
oolder age
Please consider the following details:-
•80 year old resident in care home
•Strong smelling urine, but clear looking
•Increasing confusion over 2 days
•No history of fever, temp 37.4°C.
•Has had antibiotics in past for suspected UTI
What else to ask?
Signs or symptoms of sepsis or pyelonephritis
➢New or worsening UTI symptoms: dysuria, urgency, incontinence, frequency
➢Suprapubic pain
➢Visible haematuria
➢Symptoms of other infections
➢Previous antibiotics and duration
➢Other causes of delirium
➢Risk factors: Urinary Catheterisation, hospitalisation, operations
➢Hydration
Suspected UTI in over ’65’ year olds
- Do not use urine nitrite and leukocyte dipsticks
- Use flowchart to help with management of suspected UTI
•Consider: post-menopausal syndrome
•Think pyelonephritis and sepsis
•Exclude other causes of delirium – PINCH ME
•Always safety-net
Set up nitrofurantoin as default antibiotic unless upper UTI
Actions to help and inform your progress
1.Share the TARGET older adult UTI patient leaflet during consultations
2.Do a UTI audit
3.Do the RCGP online UTI module
4.Use stand-by rather than daily prophylaxis for recurrent UTI and review 6 monthly for need
Please consider the following details:
80 year old resident in nursing home
•No confusion/delirium
•New dysuria
•New incontinence
•Temperature 37.5°C
•Received antibiotics previously for suspected UTI
•eGFR 48
•No allergies
What antibiotic if any, would you use to treat this patient?
Use nitrofurantoin first line if GFR>45 ml/min
100mg m/r BD,
•Trimethoprim if culture shows susceptible 200mg BD
As increased resistance in elderly, if giving antibiotics
•always safety net,
•send urine for culture & susceptibilities
•Advise pain relief and self-care
•Share a leaflet
UTI NICE/ PHE guidance:
Antibiotic choice
Second line if eGFR <45ml/min
pivmecillinam 400mg initial dose, then 200mg three times a day for 3 days
•fosfomycin 3g single dose sachet in women
The NICE guideline for lower UTI and prevention?
•no evidence found to support the use of cranberry products or urine alkalizing agents to treat a UTI
NICE guideline for recurrent UTI - prevention?
some women with recurrent UTI may wish to try cranberry products (evidence of benefit is uncertain and there is no evidence of benefit for older women)
•some women with recurrent UTI may wish to try D‑mannose supplements if not pregnant - 200 ml of 1% solution once daily in the evening
•Another option could be methenamine hippurate
National guidance for pyelonephritis
Action Planning for your UTI management
- Do not use urine nitrite and leukocyte dipsticks
- Use flowchart to help with management of suspected UTI
•Consider: post-menopausal syndrome
•Think pyelonephritis and sepsis
•Exclude other causes of delirium – PINCH ME
•Always safety-net
•Consider back-up prescription in those with mild symptoms - Set up nitrofurantoin as default antibiotic unless upper UTI
Actions to help and inform your progress
1.Share the TARGET older adult UTI patient leaflet during consultations
2.Do a UTI audit
3.Do the free RCGP online UTI module
4.Use stand-by rather than daily prophylaxis for recurrent UTI and review 6 monthly for need
Action planning for your surgery
Agree antibiotic choice in line with local guidance and have formulary available to all
2.Agree diagnostic tests in line with PHE Diagnostic tool
3.Laminate the UTI diagnostic flow-chart
4.Set up computer reminders for leaflets & back-up prescriptions
5.Do a practice UTI audit
6.Encourage others to do the RCGP Management of UTI free online course
7.Stop practice staff using urine dipsticks with nitrite and leukocytes in elderly patients
8.Encourage non-medical staff to watch the HEE UTI video
