I cultured PA from the time I was 15 until my last culture which was PA free (I realize it's probably still there in biofilm form, but the therapy I'm on - rotating Tobi and Cayston (both with the eFlow), high dose Ibuprofen 2x daily, PharmaNAC 2x daily, 600 mg of Azithromycin every M W F, albutoral (through eFlow) and HTS (through Pari) combined with vest before each dose of antibiotic and a nightly dose of Pulmozyme - has kicked its butt so hard that it's not even detectable now) and have cultured staph my whole life and MRSA since I was 22 or so (29 now).
My symptoms of a MRSA flare up are similar to what my symptoms of a PA flare up were. Chest felt tighter, cough was more productive, some rattling in my chest, just feeling kinda "crappy" in general. Maybe a low grade fever. Oxygen sat was usually fine (I'm usually 97-98% even after exercise). The only real difference, and how I'd know which was the cause, was the color of my mucous. PA made my mucous ever darker shades of green when it was going nuts in there; staph/MRSA made it ever darker shades of yellow.
Right now, I cough up maybe a tablespoon (or two on a "bad" day) of very, very light yellow mucous after I wake up during my morning therapy and then just clear/frothy/white/not infected looking stuff from then on. Maybe one or two little wads of the same very, very light yellow stuff in the evening before bed that built up during the day, but other than that, it's all clear looking. I'm not on any anti-staph drugs (my MRSA is resistant to Azithro); my immune system seems to handle it just fine.
When I have a MRSA flare up, I used to be given 2 weeks worth of doxycycline. It's now resistant to that. The last time I had a flareup, which was when I was still culturing PA, I was given oral Linezolid which worked about 1000x better than doxy ever did. On the rare occasions I'm hospitalized (which has always been for PA-related pneumonia), I'm given IV Vanco for the MRSA and then whatever my PA called for at the time (generally Cefepime and Meropenem).