Reducing Unnecessary Urine Cultures: Lessons From HM17

Urine cultures are among the most frequently ordered microbiology tests in hospital care, yet a positive result does not automatically indicate a urinary tract infection. Bacteria may be present without symptoms, particularly in older adults, people with diabetes, residents of aged-care facilities and patients with urinary catheters. Treating this asymptomatic bacteriuria can expose patients to antibiotics without providing clinical benefit.

The Hospital Medicine 2017 meeting in Las Vegas brought together hospitalists and other clinicians to examine practical approaches to safer, more efficient care. Its emphasis on evidence, stewardship, workflow and patient outcomes remains relevant to Australian hospitals, where antimicrobial resistance, bed pressure and diagnostic demand affect daily decisions from emergency departments to rehabilitation wards.

A central principle is simple: do not use a urine culture as a substitute for clinical assessment. Dysuria, urinary frequency, suprapubic discomfort, flank pain, fever or haemodynamic instability may justify investigation, while an isolated positive result in a patient without urinary symptoms usually does not. Delirium, a fall or cloudy urine alone should prompt assessment for other causes rather than reflex testing.

The strongest programmes combine clear indications, electronic ordering safeguards, nurse and doctor education, and feedback on testing rates. The lessons associated with HM17 resources can be adapted to local practice in Sydney, Melbourne, Brisbane and regional hospitals, while recognising Australian prescribing standards and the requirements of state-based health services.

Why Positive Cultures Can Mislead

Asymptomatic bacteriuria means bacteria are detected in urine without signs or symptoms attributable to urinary infection. It is common in older women, people living in residential aged care, patients with long-term catheters and individuals with structural or functional urinary abnormalities. A laboratory report can therefore be accurate while still being clinically unimportant.

The problem begins when the result is treated as a diagnosis rather than one piece of evidence. A patient admitted after a fall may have bacteriuria, but the culture does not prove that bacteria caused the fall. Similarly, confusion in an older patient may reflect dehydration, medication effects, constipation, hypoxia, pain or a change in environment. Antibiotics directed at an incidental urine result can cause diarrhoea, drug interactions, allergic reactions and Clostridioides difficile infection.

Routine screening is appropriate in only a small number of circumstances. Pregnancy is a recognised exception because untreated bacteriuria can lead to significant maternal and fetal complications. Screening before selected invasive urological procedures that breach the mucosa may also be indicated. Outside such settings, testing should be guided by symptoms and examination rather than by urine appearance, smell or a non-specific change in behaviour.

Choosing A Better Testing Pathway

A practical pathway starts before the specimen is collected. The clinician should document the symptom or clinical concern, check whether the patient has a catheter, and consider whether another diagnosis better explains the presentation. If infection is suspected, urinalysis may support decision-making, but it should not become an automatic trigger for culture in every patient.

Catheter-associated bacteriuria deserves particular care. Long-term catheterisation almost guarantees bacterial colonisation over time, so a positive culture without compatible symptoms is expected. When a catheterised patient has a genuine infection, replacing an old catheter where clinically appropriate and collecting a properly obtained specimen can improve interpretation. Routine catheter changes or cultures to “check clearance” are not useful.

Australian hospitals can build these principles into local policy without requiring expensive technology. A metropolitan emergency department might remove urine culture from standing admission bundles, while a rural service may use a concise paper algorithm supported by telephone microbiology advice. In New South Wales and Victoria, the pathway should align with local antimicrobial stewardship teams, pathology collection practices and state health service protocols rather than relying on a generic international order set.

Matching Clinical Signals To Action

The following framework separates findings that warrant assessment from findings that commonly lead to unnecessary treatment. It is designed for bedside discussion, order-set development and audit rather than as a replacement for clinical judgement.

Laboratory reporting can reinforce this distinction. Comments such as “mixed growth may indicate contamination” or reminders that bacteriuria without symptoms generally does not require antibiotics can interrupt automatic prescribing. The wording must be carefully designed: an alert that is too broad may be ignored, while an overly restrictive message can delay care for a patient with sepsis or an atypical presentation.

Measurement should include more than the number of cultures ordered. Useful indicators include cultures per 1,000 occupied bed-days, the proportion obtained without documented urinary symptoms, antibiotic starts linked to a positive culture, repeat cultures within a short interval and cases of inappropriate treatment. Reviewing a sample of charts helps distinguish a genuine improvement from a fall in ordering caused by incomplete documentation.

Making Stewardship Part Of Daily Work

Behaviour changes when the safer choice is convenient. Electronic medical records can require an indication before a culture is ordered, display pregnancy and procedure exceptions, and offer a “do not culture” option for isolated delirium or cloudy urine. Such safeguards should allow an override with a brief clinical reason, since rigid rules are unsuitable for unstable or immunocompromised patients.

Education works best when it is short, repeated and linked to actual cases. A five-minute discussion during a ward round can explain why a positive culture did not represent infection in a recent patient. Nurses, junior doctors, pharmacists, emergency clinicians and laboratory staff should receive the same message, since any one of them may initiate testing or influence the response to a result.

Daily coordination tools can support this approach by making diagnostic uncertainty visible. For example, teams reviewing daily goals sheet data can include an explicit question: “Does this patient have urinary symptoms or a valid screening indication?” That prompt links urine stewardship to broader ward communication, rather than treating it as a laboratory issue in isolation.

Feedback should be timely and non-punitive. A monthly report showing that one ward reduced cultures while maintaining safety is more persuasive than a distant annual target. In Australia, local comparisons can be useful: a large Melbourne teaching hospital may benchmark against similar medical wards, whereas a small Queensland or Western Australian service may track its own baseline and review every clinically significant missed or delayed diagnosis.

Recommendations For Safer Ward Practice

A sustainable programme can begin with a small number of consistent actions:

• Remove automatic urine cultures from admission, delirium and fall assessment bundles unless a valid indication is recorded.
• Use a symptom-based order prompt that clearly identifies pregnancy and selected invasive urological procedures as exceptions.
• Teach staff that cloudy urine, odour, pyuria, bacteriuria, falls and delirium alone do not establish urinary infection.
• Review antibiotic prescriptions linked to positive cultures and provide feedback to the treating team.
• Pair culture reduction with safety monitoring, including sepsis recognition, treatment delays and clinically significant urinary infections.

Patient communication is equally important. Patients and families may expect a test when someone becomes confused or develops a fever, and declining to collect urine can appear like inaction. Clinicians can explain that bacteria are common in urine, that unnecessary antibiotics have real harms, and that the team is looking for the cause most likely to respond to treatment.

Australian settings also require attention to access and equity. A patient transferred from an aged-care home in Adelaide may arrive with a recent positive culture and a request to continue antibiotics, while a remote patient may have delays in pathology transport or limited access to specialist review. The response should be based on symptoms, examination, previous microbiology and clinical stability, with early consultation when the situation is complex.

A daily ward huddle can make the process reliable: identify patients with new fever or confusion, confirm whether urine symptoms exist, check pending cultures, and stop antibiotics that were started solely for asymptomatic bacteriuria. The immediate next step is to audit the previous month’s urine cultures on one medical ward and classify each order by symptoms, indication and treatment outcome.