Hi.I Have Itchy Armpits. I Had A Test And It

Hi.I have itchy armpits. I had a test and it came back with e coli. I was on a course of antibiotics for a week. This was two months ago. My condition is back. My girlfriend had Mersa on her leg from a punch biopsy a few weeks ago. She was on a course of antibiotics for a week. I need some advice.Thank you. Tom