Transcript UTI - bpac

The laboratory investigation
of urinary tract infections
Contents
• Key messages
• Introduction
• Uncomplicated vs complicated UTI
• When is urine culture not helpful?
• When is urine culture helpful?
• Testing for asymptomatic bacteriuria
• Chlamydia trachomatis urethritis
Key messages
•
Women with symptoms of uncomplicated UTI do not
require a urine culture
•
Screening for asymptomatic bacteriuria is not
recommended except in pregnant women
•
Chlamydia trachomatis urethritis can cause similar
symptoms to a UTI
Contents
Introduction
•
Approximately 50% of all women will have a UTI, and 25%
of these will experience recurrent infections
•
In 2005, almost 800 000 urine cultures were performed in
NZ at a cost of approx $12.5 million
•
Patients with asymptomatic bacteria do not benefit from
antibiotic treatment
•
Consider C. trachomatis infection if patients present with
symptoms of a UTI + suspicious sexual history
Contents
Uncomplicated versus complicated UTI
•
People with symptoms of uncomplicated UTI do not
require a urine culture. They can be treated
empirically and no follow-up is required unless
symptoms do not improve.
•
People with complicated UTI require urine testing for
culture and susceptibility testing
Contents
Uncomplicated UTI…
Classic presentation:
• dysuria, frequency
• urgency
• suprapubic pain
Occurs in women with a normal, unobstructed
genitourinary tract.
Most frequent in young sexually active women.
Complicated UTIs are those occurring in…
• Men
• Children
• Pregnancy
• People with suspected pyelonephritis
• People with recurrent UTI
• Failed antibiotic treatment or persistent symptoms
• Catheterised patients
• Hospital-acquired infections
• Recent urinary tract instrumentation
• People with abnormalities of genitourinary tract
• People with renal impairment and
• People with impaired host defences
Urine culture is not helpful for women with
uncomplicated lower urinary tract infections as it does
not improve outcomes.
•
In women with classical presentation of uncomplicated
UTI, treatment can begin based on the strength of
clinical presentation.
•
In women with dysuria and vaginal symptoms consider
both a UTI and STIs.
•
A dipstick positive to nitrites or leukocytes has a
probability of a UTI of about 80%
•
A dipstick negative to both nitrites and leukocytes, has a
probability of a UTI of about 20%.
Contents
When is urine culture helpful?
Urine culture should be performed for:
1.
Women with a UTI with complicating features
2.
All pregnant women
3.
Men with suspected UTI
4.
Suspected acute pyelonephritis
5.
Prostatitis
Contents
Complicating features in women include:
•
Abnormal urinary tract e.g. stone, reflux, catheter,
•
Impaired host defences e.g. pregnancy, diabetes,
immunosupression,
•
Impaired renal function,
•
Suspicion of pyelonephritis,
•
More than three UTIs in one year, or
•
UTI recurrence within two weeks.
Contents
Urine culture is recommended for pregnant women
Women with asymptomatic bacteriuria in early
pregnancy have a 20-30 fold increased risk of developing
pyelonephritis, premature delivery and low birth weight
infants.
All pregnant women should be screened for
asymptomatic bacteriuria at 12-16 weeks gestation.
If bacteriuria is detected by screening, the patient should
be treated and a urine culture performed monthly
throughout the pregnancy
Contents
Urine culture is indicated for lower UTI in Men
All UTIs in men are considered complicated, therefore a
urine culture is indicated, even if the urine dipstick is
negative.
Contents
A urine culture is indicated when acute pyelonephritis is
suspected
Dipstick testing of the urine may be useful if clinical findings
are equivocal
Antibiotics should be commenced while waiting for culture
results
Post-treatment urine cultures are recommended one to two
weeks after antibiotic therapy
Contents
Acute Prostatitis
Signs and symptoms of acute prostatitis include fever,
dysuria, pelvic or perineal pain, and cloudy urine
Urine culture should be performed
If urine culture is negative, STIs (C. trachomatis, N.
gonorrhoea) should be excluded.
Contents
Chronic Prostatitis
Chronic prostatitis should be considered in men with
dysuria and frequency, no signs of acute prostatitis, and
with recurrent UTIs.
Gram-negative bacilli are most common cause, but
enterococci and Chlamydia have been associated with
chronic infection.
Contents
Screening for asymptomatic bacteriuria
Screening for asymptomatic bacteriuria is not recommended in:
1.
Non pregnant women
2.
Elderly people
3.
People with indwelling urinary catheter.
4.
People with spinal cord injuries.
The prevalence of asymptomatic bacteriuria varies from 1-5% to
100% in selected population groups.
Asymptomatic bacteriuria is a microbiological diagnosis based on
the isolation of a specified count of bacteria in the absence of
signs of UTI.
Contents
Testing for asymptomatic bacteriuria not required in
elderly people
Asymptomatic bacteriuria in the elderly occurs
frequently.
There is no benefit from treating asymptomatic
bacteriuria.
The diagnosis of UTI in this age group should be made
based on clinical signs and symptoms.
Contents
Regular urine culture or dipstick testing is not indicated
for people with in-dwelling catheters
All in-dwelling catheters eventually become colonised
with bacteria.
Contents
Asymptomatic bacteriuria and people with spinal cord
injuries
People with spinal cord injuries have a high prevalence of
bacteriuria, as well as high incidence of symptomatic
urinary tract infection
Urine culture should be performed when UTI is suspected,
for example: when the patient has non-specific symptoms,
such as vomiting and increased spasticity.
Contents
Chlamydia trachomatis urethritis
Always consider C. trachomatis urethritis when UTI is
suspected
C. trachomatis urethritis is commonly asymptomatic, but may
present with dysuria
C. trachomatis infection should be considered when a UTI is
suspected and the patients has a suspicious sexual history
Sterile pyuria (white cells in the urine but no urinary pathogen
isolated) or positive leucocyte esterase test on urinalysis may be
due to urethritis rather than a UTI
Contents
Testing for C. trachomatis
Diagnosis of C. trachomatis urethritis in men, and
screening in men and women:
– Testing can be performed on a first pass urine
sample (no urination for one hour prior to
collection)
– Urethral swabbing in men or women has little
advantage over urine testing. It may also be painful
and poorly tolerated.
In women endocervical swabs, high vaginal swab and urethral
sample (either first-catch urine or urethral swab) will exclude
most causes of genital tract infection.
Contents
Positive C. trachomatis results
If C. trachomatis infection is detected on a urine sample, a
complete STI evaluation is recommended to exclude coinfection with other sexually transmitted bacteria, protozoa
and viruses.
Resources available from bpacnz on the lab investigation
of UTIs include:
Evidence based guide ‘Laboratory Investigation of UTIs’
Interactive online quiz
Quiz feedback
UTI Clinical Audit pack for general practice
Individual UTI investigation feedback for GPs
visit
www.bpac.org.nz