Which of the following organisms is most commonly associated with catheter-associated urinary tract infection… - RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Applied Microbiology & Infection control

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Explanation

Escherichia coli is the most common cause of catheter-associated urinary tract infections (CAUTI).
This bacterium is a normal inhabitant of the human gut, and its proximity to the urethra allows for easy contamination of the perineal area and subsequent ascension along the catheter into the bladder.
Textbook evidence confirms that E. coli is the leading pathogen for both community-acquired UTIs and hospital-acquired UTIs, including CAUTI.
The mechanism of infection involves colonization of the periurethral area and formation of a biofilm on the catheter surface.

Option A: While Pseudomonas aeruginosa is a significant pathogen in CAUTI, it is the second most common cause, not the most common. It is more frequently associated with long-term catheterization and antibiotic resistance.
Option C: Staphylococcus aureus is a much less frequent cause of CAUTI compared to gram-negative bacilli like E. coli. It is more commonly associated with skin infections or bacteremia that seeds the urinary tract.
Option D: Klebsiella pneumoniae is a notable cause of hospital-acquired infections, including CAUTI, and is often multidrug-resistant. However, it is statistically less common than E. coli.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Catheter-Associated Urinary Tract Infections (CAUTI) as background academic context rather than a clinical decision trigger.
The primary nursing role in managing CAUTI is prevention. Nurses are responsible for implementing evidence-based bundles to reduce infection rates, which include ensuring aseptic technique, maintaining a closed drainage system, and advocating for timely catheter removal.
Understanding that E. coli is the most common cause reinforces the importance of perineal hygiene, especially in female patients, to reduce the risk of fecal flora contaminating the urinary tract.
What if? If a patient with a catheter develops a UTI and has recently been treated with multiple antibiotics, the nurse should have a higher suspicion for a resistant organism like Pseudomonas or Klebsiella, not just E. coli. This influences the potential need for broader empirical antibiotic coverage pending culture results.

How to Approach the Question

First, identify the key phrases in the question: "most commonly associated" and "catheter-associated urinary tract infections (CAUTI)".
This is a factual recall question asking for the most prevalent microbiological cause of a specific condition.
Recall or reason that urinary tract infections are most often caused by bacteria originating from the gut and perineal area.
Evaluate the options. All are known pathogens, but E. coli is the most common commensal of the gut and therefore the most likely to cause an ascending infection, especially when a foreign body like a catheter is present.
Confirm this by remembering that E. coli is the number one cause of UTIs in general.
Therefore, select Escherichia coli as the most statistically probable answer.

Concept Tested & Keywords

Concept Tested: Etiology of Catheter-Associated Urinary Tract Infections (CAUTI)
Stem keywords: catheter-associated urinary tract infections, CAUTI, organism, most commonly
Lead-in keywords: Which

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