What is mycoplasma hominis & ureaplasma urealyticum? Is serious?

I am planning to get pregnant this year. My husband and i are preparing for it, so we took PCR test and my husband has mycoplasma hominis and ureaplasma urealyticum, but i don't have. I made research on the internet and it is STD(sexually transmitted dicease). We both are very shocked on the result. Some people say these are very common bacterias and don't need to cure as these exist in human body. Any information ladies?