Not so sure about the middle east specifically but I travelled around Africa with no problem. Immunisations are fine and should not afect UC as long as they are not live vaccinations! As we are immunosuppressed we cannot have live vaccinations so I went without my Yellow Fever jab and, luckily, was ok.
Also, taking sanitizing hand wash and taking vitamins and probiotics and only drinking bottled water - the usual advice all help.
Plus, I took some antibiotics recommended by my nurse in case of a 'bug' and also a course of steroids just in case.