A Partnership between NHS Kent and Medway, Dartford and Gravesham NHS Trust, Maidstone and Tunbridge Wells NHS Trust, East Kent Hospitals University NHS Foundation Trust and Medway Hospital NHS Foundation Trust Kent and Medway Pathology Network Kent and Medway Microbiology Catheter Urines Policy A catheter specimen of urine (CSU) is defined as a specimen of urine taken aseptically through the port (after cleaning with chlorhexidine impregnated swabs) of an indwelling catheter. To prevent a healthcare associated infection, every effort must be made to avoid an indwelling catheter (please see respective trust policy). If a catheter is inserted for a good clinical reason, it should be removed as soon as it is no longer required. Catheter urines should not be submitted to the Microbiology laboratory unless the patient has clinical symptoms, e.g. loin pain, fever, supra-pubic pain or septicaemia that warrants an investigation. ACCEPTANCE CRITERIA Catheter Specimen of Urine Urine taken aseptically through the sampling port of an indwelling catheter Relevant clinical details Loin/flank pain, costovertebral angle tenderness Fever/Rigors Supra-pubic pain/acute haematuria Septic shock/Hypotension/tachycardia Increased respiratory rate Altered mental state/new onset delirium Pre-op check for urological surgery In Spinal cord injury: spasiticity, lethargy hyperreflexia, sense of unease NOTE: all CSUs or Bag urines from children should be cultured regardless of the clinical details provided. BACKGROUND Submitting catheter urines for examination in the microbiology laboratory has been traditional practice in many hospitals, particularly after abnormal dip-stick urine testing, but cultures from catheters are misleading, as they reflect colonization, and could lead to inappropriate administration of antimicrobials. Urine taken in the circumstances described below is not considered to be a CSU and should be labelled as “Urine”. This is important as the laboratory processes ‘urines’ and ‘CSU’ differently. • • • Taken post retention albeit through a catheter From short term urinary catheters for urogynaecological surgery From patients with intermittent catheterisation ‘Bag’ urines, i.e. urine collected from stoma bags or indwelling catheters, are often colonised by organisms. The criteria have not been established for differentiating asymptomatic colonisation of the urinary tract from symptomatic infection1. Urine cultures may not reflect bladder bacteriuria because sampled organisms may have arisen from biofilms on the inner surface of the catheter2. When submitted for investigation, these specimens of urine often produce monoclonal and polyclonal cultures providing little, if any, useful information that would benefit patient management. Similarly, colonization of urinary catheters soon after insertion decreases the specificity of urine culture for the diagnosis of urinary tract infection. Web page: “www.kmpathology.nhs.uk” 21st Century Techniques bringing you faster, more accurate, diagnosis POL-KPN-MIC-0001 Version 2.0 Review date: July 2014 Page 1 of 2 SUPPORTING EVIDENCE Catheter associated bacteriuria is usually asymptomatic and is not synonymous with clinically significant infection. Bacteriuria occurs in 10 – 20% of patients who are catheterised, but urinary tract infection in only 2 – 6%3. Organisms originating from the patients' perineal flora may be introduced to the bladder during catheterisation, or via the periurethral route along the external catheter surface, or the intraluminal route as a consequence of faulty catheter care4. In patients’ catheterised long term (>30 days), prevalence of bacteriuria is virtually 100%: infecting strains change frequently and polymicrobial bacteriuria may be present5. Treatment of asymptomatic bacteriuria has not been shown to be of any benefit in reducing complications in patients who are catheterised5 and is likely to encourage the emergence of resistant strains. Bacterial counts may be affected by the administration of medication or fluids that increase urine flow, rapid transit of urine from the catheterised bladder, or colonisation with relatively slow growing organisms such as Candida species3. Bacteraemia, most commonly Gram-negative, occurs more commonly in patients with UTI and develops in 1 – 4% catheterised patients with urinary tract infection causing significant morbidity (increasing hospital stay and costs). It has a mortality of 13 – 30%1. Patients presenting with a high fever, rigors (perhaps associated with renal angle tenderness) and, occasionally, confusion (in elderly patients) would usually indicate the need for investigation of urine specimens. However, patients with these indications would be given intravenous antimicrobial therapy without delay. Culture of urine specimens in such cases provides little further useful information for managing the patient. For patients that do not respond to treatment or are immuno-compromised, a blood culture should be submitted for investigation rather than a specimen of catheter urine. In some cases, where a patient presents with relevant clinical symptoms such as loin pain, fever, supra-pubic pain or sepsis, urines collected from the sampling port can be useful in determining whether infection is present or not. However, the quality of the specimen collected and clinical circumstances in the individual patient are critical in the interpretation of culture results. A CSU that is cloudy or offensive should not automatically be sent for testing. Therefore, in most cases submitting catheter urine specimens is unnecessary in terms of patient management and uses resources that could be re-directed to other areas of patient care. Dr Rella Workman – Medway NHS Foundation Trust 26th July 2012 Endorsed by the Kent and Medway Pathology Network Microbiology Sub Group References 1. Stamm WE. Catheter-associated urinary tract infections: epidemiology, pathogenesis, and prevention. Am J Med 1991; 91: 65S-71S. 2. Bergqvist D, Bronnestam R, Hedelin H, Stahl A. The relevance of urinary sampling methods in patients with indwelling Foley Catheters. Br J Urol 1980; 52: 92-5. 3. Garibaldi RA. Catheter-associated urinary tract infection. Current Opinion in Infectious Diseases 1992; 5: 517-23. 4. Stamm WE, Stapleton AE. Approach to the patient with urinary tract infection. In: Gorbach SL, Bartlett JG, Blacklow NR, editors. Infectious Diseases. 2nd ed. Philadelphia: WB Saunders Company; 1998. p. 943-54. 5. Warren JW, Tenney JH, Hoopes JM, Muncie HL, Anthony WC. A prospective microbiologic study of bacteriuria in patients with chronic indwelling urethral catheters. J Infect Dis 1982; 146: 719-23. 6.Diagnosis, prevention and treatment of Catheter-associated urinary tract infection in asults:2009 International Clinical practice guidelines from the Infectious Diseases Society of America. CID 2010:50 7.management of suspected bacterial urinary tract infection in adults: a national clinical guidance. SIGN 88 July 2006 Other associated policies 1. Rothwell R. Indwelling urinary catheters (short / long term). Dartford & Gravesham NHS Trust, 2008. 2. Preventing Infections associated with indwelling catheters. Medway NHS Foundation Trust, 2008 Page 2 of 2 POL-KPN-MIC-0001 Version 2.0 Review date: July 2014