<prompt> Which one of the following gram positive organism is most common cause of UTI among sexually active women-Staphylococcus epidermidisStaphylococcus aureusStaphylococcus saprophyticusEnterococcus  <response>: Ans. is c i.e., Staphylococcus saprophyticus Staph saprophyticus . Staph saprophyticus may be present on normal human skin and the periurethral area and can cause urinary tract infection, paicularly in sexually active young women. . Staph saprophyticus strains causing UTI are usually sensitive to most antibiotics, except nalidixic acid. . Staph saprophyticus is novobiocin resistant. 