Sounds like this one is a determined fecker. It can seem to be cured after treatment but if it's a strong infection...
Here are my tips posted previously:
2 heaped tsps of D-Mannose straight away (tabs or powder - I prefer the powder - all available in health food shops or internet) - get your supplies in for next time
Triple strength cranberry tablet DAILY even when you don't have anything wrong (not cranberry juice - forget the juice...too late!)
Horsetail tablet (3 per day)
If possible, keep some Trimepothan (sp) or whichever antibiotic you have had before when suffering the same thing as you may be immune to whichever
Ibuprofen or whatever to stave off niggly discomfort
Lots and lots of water - down 2 pints if you can straight away. NO caffeine obvs.
Folks say bicarb in water but I don't bother or those sachets.
Daily probiotic
Wash with hot water just over your urethra after unexpected splatty poos. An oval cotton pad doused in HOT but not hot water which is uncomfortably hot. This has a good chance of killing any germs before they get in but no guarantees
Dab a tiny bit of oregano oil over your urethra - just over but not in! It'll sting for 10 seconds and you'll wish you hadn't done it but it is very effective and it is a totally natural and safe anti-biotic
Medical clause: of course see the doctors
I keep all my supplies in the cupboard just in case. There's nothing more miserable than cystitis.