hmm I suppose it is possible - cystitis as I understand it is when bacteria from your rectum manages to make it into your urethra (where you wee from) when conducting a smear the nurse will insert a speculum and use a lubricant, this may move bacteria as its inserted or removed. Or even after the test when you carry on as normal you may be more suseptable because of the lubricant in your underwear?
I wouldnt worry I used to suffer bady with cystitis and eventually managed to flush it out naturally with water and a better diet after spending a few years relying on antibiotics and havent had a reccurence since. Sorry to hear you had this experience following two smears though - I'ts not very plesant.
Maybe next time you are due a smear, make sure you rinse before the apt and afterwards to reduce your risk ? Drink lots of water and cranberry juice a day before and afterwards.
If you are really concerned mention on it to your doctor.