Not to freak you out, but MRSA is everywhere.
Having worked in hospitals, and having been a patient, I know that all admitted patients are tested upon admission. People can have it and not know it, especially if their immune systems are weakened.
At the hospitals, we are trained to sanitize our hands before and after entering patient rooms EVERY SINGLE TIME, even if we've had gloves on.
I was around plenty of patients who tested positive for MRSA aside from their initial condition, and I never contracted it.
MRSA is a staph infection that is resistant to certain types of antibiotics, but that doesn't mean it isn't treatable.
I certainly understand your being nervous. First, I would make sure that your niece actually has it. You said you "think" she was diagnosed.
If your brother confirms it, I would just tell him that you are nervous about your child getting it. If your child is healthy, chances are slim if you take precautions. If you really, really just aren't comfortable, the sooner you say something the better so that they can make other babysitting arrangements.
I found the following information..........
How Can I Protect Myself?
MRSA may sound scary because it is resistant to some antibiotics. But it's actually easy to prevent MRSA from spreading by practicing simple cleanliness.
Protect yourself by taking these steps:
•Wash your hands often using plain soap and water for at least 20 seconds each time. You might also want to carry alcohol-based instant hand sanitizers or wipes in your bag for times when you can't wash your hands.
•If you have a cut or broken skin, keep it clean and covered with a bandage.
•Don't share razors, towels, uniforms, or other items that come into contact with bare skin.
Serious cases of MRSA are still rare. By taking these easy prevention steps, you can help keep it that way!
Reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: August 2011
Best wishes.