Look out, world — chlamydia’s getting clever, along with a whole host of other STIs. About a million people sexually transmit an infection every day around the world, according to the World Health Organization, and a lot of them are becoming harder to treat.

The primary concerns are chlamydia, gonorrhea, and syphilis. All three are developing increasing resistance to anti-bacterial drugs, in part because doctors are prescribing them too much and patients aren’t taking them correctly.

The consequences of an untreated infection can be severe, and can also expose people to a greater risk of transmitting HIV. The WHO is recommending that local officials monitor infection rates more closely, and advise doctors when they see something unusual in transmission rates. Than could help prevent over-prescription, and might indicate where more intervention is needed to ensure compliance by patients.

The WHO also said that doctors should concentrate their anti-syphilis efforts on one particular drug, known as benzathine penicillin. You may be familiar with that one — it’s one of those grueling shots that goes into your butt.

And of course, there remains an even more sure-fire way to slow infection rates: safe sex. Condoms are the best line of defense when hooking up, as well as frequent testing and disclosing your status.