Drinking alcohol will not cause UTIs. Unless, of course, while drinking alcohol a person does not observe hygiene practices normally carried out such as wiping from front to back for a female and completely emptying the bladder. However, drinking while having a UTI could worsen the symptoms.
Alcohol can possibly irritate the urinary tract. It doesn't directly cause UTIs but if you're trying to avoid UTIs you should not drink alcohol, sugar or caffeine.
A UTI (Urinary Tract Infection) is bacterial infection, which occurs when one of two things happens on a frequently, not urinating after sex, or 'holding it' when you have to urinate. Drinking will make you have to urinate more, so if you do not go when you need to, then yes it could be a catalyst, but not the cause.