Ureaplasma..anyone heard of it?

I've posted many times concerning a yeast infection that's became BV which turned into a UTI and back to yeast w/ a UTI. None of the Antibiotics have worked and it's been a year since this started. Still itchy, raw vagina. Now my Dr. Says its Ureaplasma. What is it? Will it ever go away. Negative on all STDs btw. Help please.