Husband Has Large Red Sores On His Lower Leg. Doctor

Husband has large red sores on his lower leg. Doctor he went to see told him it was MRCA but didn't explain other than it is a bacterial infection. MRCA is very close to MRSA! She put him on antibiotics and made him an appointment with a vascular surgeon. She did not tell him to isolate himself., but we are supposed to be in a church children's play tomorrow night. None of her explanation makes since or he just can't remember. He is 70 years old. He has had these bad looking sores for months now. Getting more of them now. What is MRCA?