No offense taken, it's simply the truth. It took one time over at the living with HIV for a girl to get it. It took one sexual act for my friend to contract herpes, one time over for some of the teens at the teenage pregnancy board. It takes one time for a lot of people on these boards, and luckily a lot of people can escape that one time. But it happens, and it's important people understand that and don't minimize the risk.
No offense, but the line "it only takes one time..." is used to frequently. It could take one time or it could take a few times, it depends on the viral load of the infection for contraction to occur. It would be like saying, "It only takes one sperm to get you pregnant..."; then why do men ejaculate more than one?
Also, if it's a throat infection, they would need to take typical std panel testing PLUS oral swab testing if she is having issues with her throat. The typical std panel does not normally test for throat infections.
It only takes one time with one person to catch an STD. Both of you need to be tested for all STDs.