Mycoplasmas are the smallest free-living microorganisms known. They are different from other types of bacteria as they are difficult to culture and identify. The urine test is used to identify mycoplasma hominis, a bacterial infection that affects the urinary tract. It generally spreads through sexual contact or from an infected mother to infant at childbirth. The bacteria generally show symptoms and affects those with weakened immune systems. Symptoms include pain during urination, irritation or swelling of the urethra or genital area, abnormal discharge or unusual odour.