Which amongst following is the most common cause of UTI

Ans. (a) InstrumentationRef: Harrison 18th ed. / 288* Urethral catheterization is the single most important predisposing factor in the development of nosocomial urinary tract infection. Cystoscopy may be followed by a transient bacteremia.* The most important risk factor for bacteriuria is the presence of a catheter. Eighty percent of nosocomial UTIs are related to urethral catheterization, while 5-10% are related to genitourinary manipulation. Catheters inoculate organisms into the bladder and promote colonization by providing a surface for bacterial adhesion and causing mucosal irritation.