Hello. Thanks for writing in.
When was her last heat cycle?
Are the mammary glands enlarged or just the nipples?
Are the swollen nipples painful or uncomfortable if you press on them?
What about any pain when you press on the corresponding mammary glands?
I would normally reserve ciprofloxacin if the infection doesn't respond to either a penicillin or cephalosporin antibiotic, but it is definitely an option. While generally safe for dogs, I would just check with your vet to make sure it is safe for her, and that you have enough to at least treat for 3 weeks. More information on it use in dogs is on the website below. Hope this helps.