Microbiology Enterobecteriaceae 44675821 Most common causative agent of UTI in females - A Staph saprophyticus B E.coli C Klebsiella D Proteus High-Yield Explanation Ans. is 'b' i.e., E. coli o E. coli causes 80-90% of acute uncomplicated bacterial lower tract infections (cystitis) in young women.