sudden bad body odor

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I am a 56 year old male and I suddenly have bad BO under my arms, within an hour after showering it begins, even after using the same deodorant and anti-perspirants I've always used, I even tried new ones, but no help. It's very embarrassing. I also use antibacterial soap. I read that you had put on an old t-shirt when you were painting and that somehow it helped and reversed the BO. I'm a bit confused, was that a clean or a worn t-shirt ? Is it possible that I picked up bad Bo form my laundry in the public laundry machines? Thank you