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. However some experts have suggested that symptomatic CAUTI might be defined as;

Culture growth of ≥103 colony forming units (cfu)/mL of uropathogenic bacteria in the presence of symptoms or signs compatible with UTI without other identifiable source in a patient with indwelling urethral, indwelling suprapubic, or intermittent catheterisation.

Compatible symptoms include fever, suprapubic or costovertebral angle tenderness, and otherwise unexplained systemic symptoms such as altered mental status, hypotension, or evidence of a systemic inflammatory response syndrome.

Exclusion: pregnancy
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
Most CAUTIs are derived from the patient’s own colonic flora. Some of these 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 

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.
• Pyuria (white blood cells in the urine) or the appearance or smell of the urine, should not be used to diagnose a UTI in a patient with no other compatible signs or symptoms. Pyuria is a frequent finding in all catheterised patients with bacteruria, and absence of pyuria in symptomatic patients suggests a diagnosis other than UTI. Odorous or cloudy urine has not been demonstrated to be indicative of either bacteriuria or UTI. 

Risk of antibiotic resistance 
 ·      Care home resident
 ·       Hospitalisation for more than 7 days in the last 6 months 
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 culture results. If prompt treatment is required, choice should be based upon the severity of the patient's infection, the results of any past cultures, prior use of antibiotics, local resistance, and allergy status. Empirical therapy should provide coverage against gram negative bacilli and be guided by local policy. For low risk patients in whom antibiotic resistance in unlikely, a 3rd generation cephalosporin, oral or IV fluoroquinolone or oral nitrofurantoin may  be appropriate. For high risk patients, or if antibiotic resistance is suspected then a broad spectrum antibiotic may be required. Consider changing or removing the catheter before starting antibiotics in patients with symptomatic CAUTI.
Follow up 
Check response to treatment after an appropriate interval, for example 24-48 hours, depending upon clinical judgement and review urine culture results. Once antibiotic therapy has been administered the resolution of symptoms and not the absence of bacteriuria indicates that infection has been treated.
Duration guide 
Advice on the optimal duration of antibiotics is conflicting. Follow local guidelines if you have them. In their absence, depending upon the clinical response, the pathogen and the antibiotic used, the IDSA recommend 7 days in patients with prompt resolution of symptoms, or 10-14 days when there is a delayed response. A shorter regime may be appropriate in some patients such as women aged ≤ 65 years without upper urinary tract symptoms after the catheter has been removed.