Hi
@welly and Boris
UTI can occur on its own and it can come back after a course of antibiotics. A genuine bacterial infection can cause symptoms as described above - these should stop within a day or so of starting antibiotics (but always complete the course!) Sometimes piggy is better but then symptoms return after the course is finished. This suggests that the offending bacteria haven't been completely wiped out by the antibiotic but the vet might just prescribe a second course rather than an alternative antibiotic. In the UK they usually offer Baytril as the first choice but others are available. One of my pigs had such a stubborn UTI once that even after over 2 weeks on Baytril (which stopped her symptoms within 36 hours) the infection returned. She just got prescribed another 2 or 3 weeks - same thing happened and this time it stayed away. So his "2 UTIs" might just be one that didn't quite clear with antibiotics? I hope they gave you metacam or loxicom painkiller/anti-inflammatory for him too... it can sting to pee. I'd certainly go back to the vet. But there are a few other things they might want to check for:-
My George got his first and only UTI at a time when he was quite stressed about his cage mate being unwell and he was developing both arthritis and impaction which I didn't spot at first. So he was laying in one place a lot because his knees were stiff and the immobility didn't help him clear his back end so he was muckier than usual and lying in it! Result - UTI, which was treated effectively with a short course of baytril. But George is also now on daily metacam and takes glucosamine (in the form of oxbow joint support lozenges) which have helped him so much with his mobility. And he's unbunged every night! I only mention this because you have an older boy and it's worth having a vet check him over for arthritis (vet said George's knees 'creaked'!) and impaction... you can check for that yourself if you don't mind poking round his bum! It occurs in about 10% of older boys.
UTI can be a trigger for the formation of stones and calcium grit so if he is peeing freely for a few days but then you see a splodge of proper blood I'd be thinking about that. The vet can x-ray to identify these as they light up white. They will probably give him a good examination first and give his bladder a bit of a poke to see if it is tender. X-ray doesn't hurt them at all - but if the vet wants to use anaesthetic ask for more details about what type and how long he'd be under because he's getting on a bit. Don't panic too much about stones yet: they may find nothing, or they may find traces of sludge which he'll be able to pee out. Poor George had a stone develop in his penis earlier this year and it was a whopper that actually significantly blocked the tube but the vet just squeezed it out! Luckily for all it was rounded - some can be spikey and painful. The glucosamine mentioned earlier is also a useful supplement for battered bladders - piggies with something called Sterile Interstitial Cystitis (cystitis without bacterial infection that flares us every now and again) benefit from taking it. My fat girl who occasionally squeaks with gritty pee for a day or so has a 'George Lozenge' when he does, to try and protect against bladder damage.
So I guess what I'm saying is go back to the vet and be prepared for a second run of antibiotics, a good exam and maybe an x-ray. Antibiotics and metacam have to be prescribed if they are necessary, but the oxbow glucosamine can be bought online (amazon or similar) as it is just a food supplement. If you decide to add it into his diet you likely won't see any significant changes for 2-4 weeks as it takes a while to 'work'. After 2 my George seemed a bit more mobile but after a month on it I saw him scamper for the first time in ages!
Good luck Boris, and let us know how you get on x