Can resident flora cause infection?

Yes. It can so be careful

Bacteria going into your system causes infections and viruses. Your white blood cell count increases so it can fight of the infection. That's why you should always wash your hands!!!!

Bacteria, viruses, fungi, and other microbes. Mostly bacteria, if you're talking about open wounds.

Nope.

also called microflora, indigenous flora, normal flora, microbiota, the variety of nonpathogenic microorganisms that normally permanently colonize various parts of the body