I mean, reread the definition. Oddity specifically states that animals are the thing to avoid cruelty towards. Bacteria are not animals, therefore they don’t matter under this definition.
There are some microscopic animals that exist, but they still don’t really contradict the definition because of the “as far as is possible and practicable” clause. You can’t really stop your immune system from working so it’s a moot point. Hand sanitizer doesn’t matter since tmk the actual microscopic animals like tardigrades or roundworms aren’t really affected by it.