The character of Sheldon Cooper was inspired by a computer programmer personally known to series co-creator Bill Prady. He is named in honor of actor/producer Sheldon Leonard and Nobel Prize Laureate Leon Cooper.
The infection is caused by bacteria. However, excessive use may irritate you. Soda also dehydrates you, and for proper urinary health you should be drinking lots of water, and also cranberry juice. Your physician was definitely right in telling you that it could have made the bladder infection worse.
Artificial colors in soda and other food and drink do irritate the bladder and kidneys. Steer clear of them as much as you can. I have a bladder disease called interstitial cystitis. I also have to avoid caffeine -- also in Coke -- as it irritates my bladder as well.