My left armpit smell like onion sometimes but right armpit never smell

Name: 
Mara
More information: 
I have never had any smelly armpit problem. But two year ago, one day I suddenly notice I smell like onion. Then I realize only my left armpit smells like onion, but my right arm never smells. My left armpit smells when I sweat. I saw your Ted talk, I was wondering if I can transfer my good bacteria from my right armpit to my left?