Synopsis
Distinguish symptomatic catheter associated infection from expected bacteriuria, collect a valid specimen and coordinate catheter source management with appropriate antimicrobial treatment.
- Bacteriuria becomes common with an indwelling catheter; a positive culture, cloudy urine or pyuria alone does not establish symptomatic infection.
- Assess new attributable symptoms and other causes. Before applying the usual no-antibiotic bacteriuria rule, exclude pregnancy and a planned urological procedure that will breach mucosa.
- With symptomatic infection and a catheter present for more than seven days, consider removal or change as soon as possible; neither action should delay antibiotics.
Key red flags
A painful distended bladder, little urine in the bag despite bladder filling, hypotension, altered consciousness or rigors requires urgent assessment. Check for obstruction and systemic illness while arranging necessary treatment.
Investigation priorities
Obtain a specimen that represents current bladder urine.
Management branches
A sixty eight year old woman has new suprapubic pain after twelve days with a catheter.
- The catheter is still needed during recovery from postoperative bladder dysfunction. She is afebrile with stable observations, no flank pain, eGFR 61 and no relevant allergy or G6PD deficiency; examination finds no alternative cause and confirms drainage without upper tract features.
- Because the catheter has been present for more than seven days, it is changed aseptically without delaying treatment. Urine is collected from the new catheter port before nitrofurantoin modified release 100 mg orally twice daily for seven days is started for the lower-only syndrome.
Key medicines
Nitrofurantoin 100 mg modified release capsulesFor an adult with an unblocked catheter and lower-only symptomatic infection, give 100 mg orally twice daily for seven days with food.A blocked catheter needs drainage, and upper tract or prostate involvement requires another antibiotic strategy. Standard use requires eGFR at least 45 ml/min/1.73 m²; the resistant uncomplicated lower-infection exception at 30–44 needs an individual benefit–risk decision. Exclude G6PD deficiency, acute porphyria, nitrofuran or formulation hypersensitivity, and pregnancy at term, during labour or delivery. Reconcile citrate or other urinary alkalinisers, magnesium trisilicate and probenecid or sulfinpyrazone because activity, absorption or excretion can be affected. Stop and investigate new respiratory, hepatic or neurological symptoms promptly. Verify the modified release capsule; this seven-day treatment does not establish a long-term prophylaxis plan.
Cefalexin 500 mg capsulesFor catheter associated infection with upper tract symptoms in an adult suitable for oral therapy, use 500 mg orally twice or three times daily for seven to ten days.Severe illness, vomiting or suspected sepsis can require intravenous treatment and hospital care instead. Exclude allergy to cefalexin, its excipients or the cephalosporin class; clarify any penicillin reaction and seek specialist selection after a severe reaction. Check renal dose adjustment and previous resistant isolates. Monitor for antibiotic-associated diarrhoea, severe rash and neurological effects with accumulation; the named formulation does not remove the need to individualise treatment in renal impairment.