I use Revolution, as it repels as well as kills fleas, and covers a lot of other stuff as well. Including heartworm, so I don't have double dose the cats as I do the dogs.

Frontline kills fleas but does not repel them.

Advantage both kills and repels but does not cover many other parasites.

I just scanned a few articles re haemobartonella as I wasn't familiar with it. Quite a few ( but not ALL) said the cat is usually a 'carrier' even after it is all healed up. So be cautious with bringing it home to your cats would be my suggestion.