Urinary Catheters and Urinary Tract Infections

Urethral catheterization increases chances of urinary tract infections. Since a catheter is a foreign body in the bladder and urethra, it creates a good media for attracting bacteria. Catheter contamination usually from failing to conduct an aseptic technique plus catheter derived irritation from friction with the urethra make of catheterization a major contributor to both asymptomatic and symptomatic bladder bacteriuria which in turn lead to urinary tract infections.

Other contributing factors:

Aside from catheterization, chances of infection increase if the catheter is left in place for too long; the patient has another infection like diarrhea; hygiene is not observed during urine bag emptying or attaching, or the immune system is suppressed.

Common pathogenic organisms resulting from catheterization:

  • Escherichia coli, the most common.
  • Candida albicans, the next most common.
  • Pseudomonas species.
  • Enterococcus species.
  • Staphylococcus aureus.

Diagnosis:

Symptoms may be non-specific. Fever and raised leucocytes are commonly seen. When an infection is suspected and the patient can void, the catheter should be removed and a mid-stream urine specimen (MSU) sample taken for analysis. If this is not possible, a fresh catheter should be introduced and a urine sample derived from it. Expected findings include:

  • Pus in urine (pyuria).
  • More than 50 white blood cells seen under high power field (HPF).
  • Colony counts of 10-100000/ml.

More often than not, the causative organisms are more than one.

Treatment:

The first step is to remove the catheter. If catheterization is needed continuously, a new catheter should be used. If there is asymptomatic bacteriuria after 48 hours of catheter removal, antibiotics should be considered. A urine culture and sensitivity test should be done before antibiotics commencement to prevent antibiotic resistant organisms.

A 7 day course of antibiotics is enough for uncomplicated cases. But if symptoms don’t wane or respond slowly, the treatment should go on for up to 2 weeks. Depending on the doctor’s assessment and the state of the patient, treatment can be as short as 3-5 days.

Prevention:

One of the best preventive measures of catheter related urinary tract infections is to strictly observe the 2009 Center for Disease Control and Prevention (CDC) guidelines:

  • Catheterization should be done only when absolutely necessary and for the shortest possible time.
  • Patients with higher risk of catheter related UTI should be recommended other means of bladder management.
  • Antibiotics should be avoided as a routine measure for preventing infections in catheterized patients.
  • Long term catheterization should consider changing to a new indwelling catheter every 2 weeks or at the onset of an infection, whichever comes earlier.

Other preventive measures include:

  • Observing high standards of hygiene during catheter/urine bag related tasks.
  • Using a hydrophilic lubricant during catheter insertion to reduce tissue irritation and inflammation.
  • Employing silver alloy coated catheters –tests with nitrofurantoin impregnated catheters have been recorded but with no material advantage.

Summary:

The best ways to prevent catheter related urinary tract infections and their complications is to:

1.Avoid catheterization if at all possible.

2.Maintain high standards of hygiene.

3.Removing the catheter as early as possible.

4.Using appropriate medications and for the right duration when infection has already occurred.

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