Which pathogen is the most frequent cause of CAUTI?

• A. Pseudomonas Aeruginosa
• B. Escherichia Coli
• C. Enterococcus Faecalis
• D. Candida Albicans

Answer: (B)

Escherichia coli is the most frequent cause of CAUTI because it comes from the body's own gut flora and has virulence traits that make urinary tract infections easy to establish, especially when a catheter is present. Uropathogenic E. coli use specialized fimbriae to adhere firmly to the bladder lining and to catheter surfaces, which allows them to colonize quickly and resist flushing by urine. The catheter also provides a surface for biofilm formation, creating a protective community where bacteria are harder to eradicate with antibiotics and the immune system. While other pathogens like Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans can cause catheter-associated infections, they occur less frequently overall. Pseudomonas often shows up in longer hospital stays and chronic catheter use, and Enterococcus or Candida infections are more common with extensive antibiotic exposure or in immunocompromised patients.