@cazabon Did you find out what kind of bacteria you're dealing with? What does the vet say?
Marigold received Baytril (Enrofloxacin) and Convenia (Cefovecin) injections for her various skin conditions and when she was healing from her severe pododermatitis, but Convenia is risky apparently, so please be cautious with that one. This (trustworthy!) German site has a list of meds too, maybe this is somewhat helpful (with a translation app hopefully also readable): https://kaninchenwiese.de/vet/medikamenten-dosierungs-empfehlungen/
Sending nose-bumps and well-wishes to George! 