This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Most common organism causing UTI: 
Select and explain. 
A. E. coli, B. Streptococci, C. Klebsiella, D. Staphylococci saprophyticus
A: E. coli
Answer: A: E. coli 
Explanation: Ans. (a) E. coli "E. coli cause 80% of acute UTI in patients with out catheterization." Strains of E. coli causing UTI are called extraintestinal pathogenic strains of E. coli. Remember:- E. coli is MC cause of catheter associate UTI too. UTI is MC nosocomial infection. E. coli is MC cause of neonatal meningitis. E. coli is MC cause of intraabdominal abscess. Other gram negative rods causing UTI are: Proteus, klebsiella, serratia, pseudomonas, enterobacter.