Has she discussed it with her supervisor?
Who told her that directly? did she report it to anyone?
Why does she feel like this is happening? Did she have a run-in with someone?
What is her age?
It's a difficult situation sometimes because people can definitely become jealous or intimidated by another persons experience. If they are picking on her because of her age, thats against the law and they could get in trouble for it. I would tell her to try and keep a good attitude about things, 'kill them with kindness' as my mother would say, smile and let all of the nonsense run off her back. I don't know if she got the job to make friends, but if they don't want to be friends, then it's their loss. Tell her to hold out for a while longer and it may pass. It may just be because she's new. Do her job well, smile, treat her patients good, and ignore all the rest. If nothing changes in a few weeks, then she should talk to her supervisors, supervisor. She should also keep a journal on everything that has happened and does happen, including dates and times, in case she needs it.
I welcome your thoughts, let me know if you want to talk more