• Follow local guidelines, when these are available.
• Do not treat asymptomatic bacteriuria.
• Considerable clinical judgement is required to diagnose urinary tract infection (UTI) in men with an indwelling urinary catheter.
• If symptoms are severe (for example severe nausea and vomiting, confusion, tachypnoea, tachycardia, hypotension, reduced urine output), admit the person to hospital; intravenous antibiotics may be required.
• Check that the catheter is correctly positioned and is not blocked. If the catheter has been in place for more than a week, consider changing it before starting antibiotic treatment.
• If there is fever or loin pain (or both), manage as upper UTI. See the CKS topic on Pyelonephritis - acute.
• Otherwise, treat for lower UTI:
• Relieve symptoms with paracetamol or ibuprofen.
• Before starting antibiotic treatment, obtain a urine sample for culture and microscopy.
• Treat with an antibiotic for 7 days.
• If symptoms are mild, consider withholding antibiotics until the result of urine culture is available to guide choice of antibiotic.
• If treatment cannot wait for the culture results, start empirical treatment with trimethoprim or nitrofurantoin.
• Trimethoprim 200 mg twice daily, for 7 days. Trimethoprim should not be used for empirical treatment if the man has a history of recurrent infections or has taken trimethoprim within the past 12 months.
• Nitrofurantoin 50 mg four times daily, or 100 mg (modified-release) twice daily, for 7 days. The standard formulation is suitable for most people. Consider prescribing the modified-release formulation if nausea has previously been troublesome with the standard formulation, or if adherence with taking medication four times daily is likely to be poor.
• Follow up after 48 hours (or according to the clinical situation) to check response to treatment and the urine culture results.

In depth

• Ensure an indwelling urinary catheter is appropriate.
• Use an indwelling catheter only after alternative methods of management have been considered.
• Regularly review the clinical need for catheterization and remove the catheter as soon as possible.
• Use intermittent catheterization in preference to an indwelling catheter if this is clinically appropriate and is a practical option for the person.
• Prevent the introduction of infection.
• Healthcare personnel should be trained and assessed in their competence to perform urethral catheterization using aseptic procedures.
• Urine samples should be obtained from a sampling port using an aseptic technique.
• Catheters should be changed only when clinically necessary (for example to prevent blockage), or according to the manufacturer's recommendations.
• When changing catheters, antibiotic prophylaxis should only be used for people with a history of catheter-associated urinary tract infection following catheter change.
• Do not use:
• Bladder instillations or washouts.
• Prophylactic antibiotics when changing catheters in men with a heart valve lesion, septal defect, patent ductus, or prosthetic valve.
• Topical antiseptics or antibiotics applied to the catheter, urethra, or meatus — daily washing of the meatus with soap and water is sufficient.

In depth

• Review after 48 hours, or according to the clinical situation, to ensure the man is responding to treatment, and to check the results of the urine culture.
• If urine culture shows that the organism is resistant to the current antibiotic, and:
• If symptoms have not resolved, change to an antibiotic that the organism is sensitive to.
• If symptoms have resolved, consider continuing with the current antibiotic.
• If symptoms recur, start treatment with an antibiotic shown in the laboratory report to cover the infecting organism.
• If the man fails to respond to two courses of antibiotic shown by urine culture to be appropriate treatment, and compliance has been good, consider referring for assessment and investigation.

In depth

• Consider referring for assessment and investigation if the man fails to respond to two courses of antibiotic shown by urine culture to be appropriate treatment, and treatment adherence has been verified.
• If cancer is suspected, refer urgently. Refer the man to a team specializing in the management of urological cancer if:
• He is of any age, with macroscopic haematuria and urine culture fails to confirm a urinary tract infection (UTI) or the haematuria does not resolve with treatment of a UTI. 
• He is 40 years of age or older, and presents with recurrent or persistent UTI associated with haematuria.
• He is 50 years of age or older, and has unexplained microscopic haematuria — exclude causes such as the urinary catheter and infection.
• An abdominal mass is identified (clinically or on imaging) that is thought to arise from the urinary tract.
• If there is persistent microscopic haematuria, and this is not thought to be caused by a urinary catheter:
• Refer for urological assessment those men younger than 50 years of age who do not have proteinuria or raised serum creatinine.
• Refer for renal assessment those men with proteinuria or raised serum creatinine.

In depth