By Melissa Matthews / Newsweek

You’ve likely never heard of, or been tested for it, but a sexually transmitted infection that’s fairly common could now be resistant to antibiotic medications. Mycoplasma genitalium, or MG, is not a new bacteria and was first identified in the 1980s. According to the Centers for Disease Control and Prevention, it is more common than gonorrhea and chlamydia, though it's not as easily recognized as the other two.