CATHETER-ASSOCIATED URINARY TRACT INFECTIONS Hamid Emadi M.D Associate professor of Infectious diseases Department Tehran university of medical science
The most common nosocomial infection The urinary tract infection
The most common risk factor for UTI The urinary catheterisation
The most important risk factor for the development of catheterassociated bacteriuria Duration of catheterisation
Other risk factors include Female sex Older age Diabetes mellitus Bacterial colonization of the drainage bag Errors in catheter care (eg, errors in sterile technique, not maintaining a closed drainage system, etc)
EPIDEMIOLOGY Bacteriuria in patients with indwelling bladder catheters occurs at a rate of approximately 3 to 10 percent per day of catheterization Of those with bacteriuria, 10 to 25 percent develop symptoms of urinary tract infection (UTI)
PATHOGENESIS Urinary tract infection (UTI) associated with catheterization may be extraluminal or intraluminal.
PATHOGENESIS Extraluminal infection occurs via entry of bacteria into the bladder along the biofilm that forms around the catheter in the urethra
PATHOGENESIS Intraluminal infection occurs due to urinary stasis because of drainage failure, or due to contamination of the urine collection bag with subsequent ascending infection.
PATHOGENESIS Extraluminal is more common than intraluminal infection
PATHOGENESIS Rarely, there can be purple discoloration of the urine (the purple urine bag syndrome) The purple color of the urine is due to metabolic products of biochemical reactions formed by bacterial enzymes in the urine
PATHOGENESIS
Responsible Pathogens Escherichiacoli ( most common) Pseudomonas Enterococcus Staphylococcus aureus coagulase - staphylococci Enterobacter yeast
Antimicrobial resistance Organisms that cause catheterassociated UTI and asymptomatic bacteriuria are increasingly resistant to antimicrobial agents.
CLINICAL FEATURES Fever is the most common symptom Localizing symptoms may include flank or suprapubic discomfort, costovertebral angle tenderness catheter obstruction. Nonspecific findings include newonset delirium or other systemic manifestations
CLINICAL FEATURES Patients with spinal cord injury may have especially atypical and nonspecific symptoms, including increased spasticity malaise/lethargy autonomic dysreflexia.
Laboratory findings Pyuria is a common finding in catheterized patients with bacteriuria, whether they are symptomatic (ie, have UTI) or not.
Symptomatic bacteriuria (urinary tract infection ) Culture growth of 10 3 colony forming units (cfu)/ml of uropathogenic bacteria in the presence of symptoms or signs compatible with UTI in a patient with indwelling urethral, indwelling suprapubic, or intermittent catheterization.
Asymptomatic bacteriuria Culture growth of 10 5 colony forming units (cfu)/ml of uropathogenic bacteria in the absence of symptoms compatible with UTI in a patient with indwelling urethral, indwelling suprapubic, or intermittent catheterization. Or within the past 48 h
Diagnosis Appearance (cloudy urine) or smell of the urine, should not be used to diagnose a UTI
Specimen collection Ideally urine samples for culture should be obtained by removing the indwelling catheter and obtaining a midstream specimen. If ongoing catheterization is needed, the catheter should be replaced prior to collecting a urine sample for culture, to avoid culturing bacteria present in the biofilm of the catheter but not in the bladder.
Specimen collection If a sample is being collected without catheter removal, urine should be obtained from the port in the drainage system
Specimen collection In the setting of condom catheters, it can be difficult to distinguish true infection from skin and mucosal contamination In these cases, a clean catch midstream specimen should be obtained, or urine should be collected from a freshly applied condom catheter after cleaning the glans
Prevention
Catheter use only for appropriate indications
Catheter use and duration should be minimized in all patients, especially those at higher risk for catheter-associated UTI (eg, women, elderly persons, and patients with impaired immunity)
Aseptic technique Only properly trained who know the correct technique of aseptic catheter insertion and maintenance are given this responsibility
An indwelling catheter should be introduced under antiseptic conditions
Urethral trauma should be minimised by the use of adequate lubricant and the smallest possible catheter calibre
Sterile gloves Sterile drapes Site cleaning supplies Sterile lubricant Sterile catheter attached to drainage bag
Hand Hygiene & Aseptic Technique
Antibiotic-impregnated and Silver alloy catheters may decrease the frequency of asymptomatic bacteriuria within 1 week. There is, however, no evidence that they decrease symptomatic infection. Therefore, they cannot be recommended routinely
closed system The catheter system should remain closed. The duration of catheterisation should be minimal
Removal of the indwelling catheter after non-urological operation before midnight might be beneficial.
Topical antiseptics or antibiotics applied to the catheter, urethra or meatus are not recommended.
Prophylactic antibiotics Benefits from prophylactic antibiotics have never been established, therefore, they are not recommended Chronic antibiotic suppressive therapy is generally not recommended
Interval of Changing the catheter Long-term indwelling catheters should be changed at intervals adapted to the individual patient, but must be changed before blockage is likely to occur, however, there is no evidence for the exact intervals of changing catheters ( no more than 2 weeks)
Level of urine bag The drainage bag should always be kept below the level of the bladder and the connecting tube.
Routine urine culture Routine urine culture in asymptomatic catheterised patients is not recommended.
U/C before any antimicrobial therapy Urine, and in septic patients, also blood for culture must be taken before any antimicrobial therapy is started
Empirical therapy For empirical therapy, broadspectrum antibiotics should be given based on local susceptibility patterns. After culture results are available, antibiotic therapy should be adjusted according to pathogen sensitivity.
Asymptomatic candiduria In case of asymptomatic candiduria, neither systemic nor local antifungal therapy is indicated, but removal of the catheter or stent should be considered
Symptomatic CA- candiduria In case of candiduria associated with urinary symptoms, or if candiduria is the sign of systemic infection, systemic therapy with antifungals is indicated
Patients with urethral catheters in place for > 10 years should be screened for bladder cancer
Alternative drainage systems In appropriate patients, a suprapubic, condom drainage system or intermittent catheter is preferable to an indwelling urethral catheter
Intermittent catheterization There is limited evidence that postoperative intermittent catheterisation reduces the risk of bacteriuria compared with indwelling catheters
Intermittent catheterization Intermittent catheterization is associated with a lower rate of bacteriuria and UTI than long term indwelling catheterization
Asymptomatic bacteriuria Warranted only in the setting of pregnancy or prior to urologic procedures for which mucosal bleeding is anticipated. For other asymptomatic patients with indwelling catheters treatment of asymptomatic bacteriuria is not indicated
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