I saw the breast surgeon today - routine followup - and he told me it is quite rare, so they don't have a lot of data on reoccurance. However, he thought it is unlikely to reoccur again, especially as I get further and further out from radiation and surgery and as my post-radiation immune system recovers. You are right @fairydust that the infection needs an entry point and I'm not expecting any trauma to the breast from gardening, etc. I finally finished the oral antibiotics today and can start probiotics. I can't imagine anything is alive in my gut!
