<prompt> Which of the following gram-positive organism is most common cause of UTI among sexually active womenStaphylococcus epidermidisStaphylococcus aureusStaphylococcus saprophyticusEnterococcus  <response>: Staphylococcus saprophyticus is gram-positive and coagulase-negative staphylococci. Staphylococcus saprophyticus may be present on the normal human skin and the periurethral area and can cause urinary tract infection, paicularly in the sexually active women. The infecting strains are usually sensitive to most common antibiotics except nalidixic acid. Staphylococcus saprophyticus is novobiocin resistant. Reference: Textbook of Microbiology; Anathanarayan and panickers; 10th edition; Page no: 208 