Catheter-associated urinary tract infections — prevention and management

Definitions: catheter-associated bacteriuria is almost universal with long-term catheters and is usually asymptomatic and polymicrobial. CAUTI is bacteriuria plus signs or symptoms attributable to the urinary tract with no other identified source, in a patient with an indwelling catheter in place (or removed within the previous 48 hours).

Burden: urinary tract infection is among the commonest healthcare-associated infections, and historically 70–80% of hospital UTIs were attributable to an indwelling urethral catheter. CAUTI rates in low- and middle-income countries, including India, consistently exceed those reported from high-income settings.

Pathogenesis: organisms ascend extraluminally along the catheter–urethral interface or intraluminally from a broken drainage system, and establish a biofilm on the catheter surface that protects them from antibiotics and host defences. Risk rises with each day of catheterisation.

Microbiology: Escherichia coli, Klebsiella, Proteus (urease-producing, causes encrustation and blockage), Pseudomonas, Enterococcus, and Candida. Multidrug-resistant Gram-negative organisms, including ESBL producers and carbapenem-resistant Enterobacterales, dominate in Indian hospital practice.

Clinical features in older adults are non-specific: fever, new or worsening delirium, functional decline, falls, reduced oral intake, rigors, suprapubic or flank pain, or haematuria. Classical dysuria and frequency are often absent because the catheter bypasses the urethra.

Prevention — the four essential principles:

Avoid unnecessary catheterisation — insert only for defined indications; use bladder scanning, toileting programmes, external catheters and pads instead.

Insert aseptically by trained personnel, using the smallest suitable catheter and sterile technique.

Maintain a closed sterile drainage system, keep the bag below bladder level and off the floor, secure the catheter, avoid kinking, and perform hand hygiene before and after any catheter contact.

Remove as early as possible — daily review of continuing need, nurse-driven removal protocols and automatic stop-orders.

What does NOT prevent CAUTI: routine bladder irrigation, routine antiseptic or antibiotic instillation, routine systemic antibiotic prophylaxis, routine catheter changes to "clear" bacteriuria, vigorous daily meatal cleaning with antiseptics, and cranberry products.

Diagnostic (urine-culture) stewardship: do not send reflex urine cultures from catheterised patients without genuine urinary signs or symptoms; culture only when clinical criteria are met, and exclude other sources of fever first. Treating asymptomatic bacteriuria offers no benefit and drives resistance.

Management of established CAUTI: obtain cultures after replacing a catheter that has been in place for more than two weeks (a fresh specimen from a new catheter reflects bladder rather than biofilm flora); remove the catheter altogether if it is no longer needed; start empirical therapy guided by local antibiogram and severity, then de-escalate on culture and sensitivity.

Duration and supportive care: typically 7 days for prompt responders and 10–14 days for delayed response or bacteraemia; ensure hydration, correct electrolytes, exclude obstruction, abscess or stones if the response is poor, and review the ongoing need for catheterisation before discharge.

SHEA/IDSA/APIC/AHA/Joint Commission Compendium — CAUTI 2022 Update (published 2023) reorganises measures into essential practices (avoidance, aseptic insertion, closed system maintenance, early removal, urine-culture stewardship, surveillance and feedback) and additional approaches for outbreaks or persistent high rates; it also addresses routine replacement of catheters in place beyond 30 days and extends guidance to paediatric settings.

Urine-culture (diagnostic) stewardship is now a named essential practice — reducing inappropriate culturing has been shown to reduce reported CAUTI rates and unnecessary antibiotic use without patient harm.

An ISID guidance chapter (2024) adapts CAUTI prevention for low- and middle-income countries, noting persistently higher INICC-reported rates and emphasising bundle implementation, catheter-day reduction and antimicrobial stewardship — directly applicable to Indian district hospitals and NABH accreditation requirements.

Mnemonic for the bundle — "AIMS": Avoid unnecessary catheters · Insert aseptically · Maintain a closed system · Stop early (remove promptly).

Numbers: historically 70–80% of hospital UTIs are catheter-related; risk increases with each catheter-day; replace catheters in place >2 weeks before culturing; treat 7 days (prompt response) or 10–14 days (delayed response); catheters >30 days raise the replacement question.

The single highest-impact intervention is removing the catheter — say this explicitly. Examiner traps — (1) Do not treat asymptomatic catheter-associated bacteriuria. (2) Do not send a urine culture simply because the urine is cloudy or malodorous. (3) Do not rely on dysuria and frequency — delirium and functional decline are the geriatric presentation. (4) Do not use antibiotic prophylaxis or routine irrigation to prevent CAUTI. (5) Exclude obstruction, stones and abscess when a CAUTI fails to respond.

CAUTI = bacteriuria plus attributable symptoms; bacteriuria alone is not infection.

Biofilm formation on the catheter is the central pathogenic mechanism.

Risk rises with every catheter-day; early removal is the most effective prevention.

AIMS bundle: Avoid, Insert aseptically, Maintain closed system, Stop early.

Delirium or unexplained functional decline may be the only sign in an older patient.

Replace a long-standing catheter before taking the culture, then treat.

Urine-culture stewardship is now an essential prevention practice.