Catheter-associated urinary tract infections (CAUTI)

Last updated: Wednesday, March 15, 2017

These guidelines are based upon a range of information resources and may not represent your local policy. Always check for local guidelines first. If you need to refresh your knowledge about the management of uncomplicated UTI in primary care then click here.
Case definition
UTI is a common hospital-acquired infection in the UK, with the majority associated with catheter use. Click to learn more.
The catheter provides a focus for bacterial biofilm formation. The longer the catheter is in place, the higher the risk of developing bacteriuria. This may be asymptomatic, or lead to symptomatic UTI. Signs and symptoms such as fever, new onset confusion and suprapubic pain are common in catheterised patients without symptomatic UTI making diagnosis difficult. 

Clinical diagnosis: Signs and symptoms compatible with CAUTI include new onset or worsening of fever, rigors, altered mental status, malaise, or lethargy with no other identified cause, flank pain, costovertebral angle tenderness, acute haematuria, pelvic discomfort and in those whose catheters have been removed dysuria, urgent or frequent urination and suprapubic pain or tenderness.

Laboratory diagnosis: Microbiologically CAUTI is defined by microbial growth of > 10cfu/mL of one or more bacterial species in a single catheter urine specimen or in a mid-stream voided urine specimen from a patient whose catheter has been removed within the previous 48 hours.

Risk factors
The duration of catheterisation is strongly correlated with the risk of developing an infection. Click to read other risk factors.
• Female gender
• Older age
• Diabetes mellitus
• Bacterial colonisation of the drainage bag
• Errors in catheter care (e.g. non-sterile technique)
Typical pathogen profile
Some organisms almost never cause UTI in the absence of an indwelling catheter, but the catheter offers easy access to the bladder. An example is Candida spp. Candiduria is a common finding in patients with indwelling bladder catheters, particularly those with diabetes or taking antimicrobials. However, most patients are asymptomatic, and progression to candidaemia is uncommon. Click to see the usual pathogens.
Gram positive
Enterococcus spp. 
Staphylococcus aureus (more rare)

Gram negative
Escherichia coli (most common)
Proteus spp. 
Enterobacter spp. 
Pseudomonas aeruginosa 
Klebsiella spp. 

Candida albicans

Microbiology investigations
• Only culture urine if patient has clinical sepsis, not because the appearance or smell of the urine suggests bacteriuria is present.
• Culture urine before starting antibiotics.
• There is no value in urine microscopy or dipstick tests.
• Samples may not accurately represent the true pathogen and often contain several bacterial species. Interpret results with caution.
Evidence of infection 
• Refer to Case definition above.
• Do not treat asymptomatic bacteriuria (except for some special cases such as prior to some urological procedures). 
• The absence of fever does not appear to exclude UTI and hypothermia (<36⁰C) may also indicate infection.
• The presence, absence, or degree of pyuria (white blood cells in the urine) should not be used to differentiate bacteriuria from UTI. Pyuria is a frequent finding in all catheterised patients with bacteruria, and absence of pyuria in symptomatic patients suggests a diagnosis other than UTI.
• The presence or absence of odorous or cloudy urine should not be used to differentiate between bacteriuria or UTI.
Risk of antibiotic resistance 
 ·      Care home resident
 ·      Recent hospitalisation
Severity assessment
If the patient has systemic signs (e.g. fever, rigors, chills, vomiting, confusion, hypotension) consider pyelonephritis, urosepsis.
Choosing an antibiotic
Ideally base antibiotic selection on susceptibility results. Remember to check whether the antibiotic is suitable for your patient taking into account their medical history, their allergy status, their prior use of antibiotics and the results of any past cultures, as well as your local resistance patterns. NICE give recommendations for empirical treatment, but check if you have local guidelines too. Consider changing or removing the catheter before starting antibiotics in patients with symptomatic CAUTI, but do not delay treatment.
Follow up 
Check response to treatment after an appropriate interval, for example 24-48 hours, and review urine culture and susceptibility results. Switch antibiotics if necessary, ideally to a more narrow spectrum agent. If intravenous antibiotics are started, ensure that they are reviewed within 48 hours and switched to oral options is possible. Once antibiotic therapy has been administered the resolution of symptoms and not the absence of bacteriuria indicates that the infection has been treated.
Duration guide 
For adults including non-pregnant women with no upper UTI symptoms, NICE recommend 7 days of oral antibiotics. For other patients, including those with upper UTI symptoms, a longer course may be required. Consult your local guidelines too if you have them.