Skip the Antibiotic routine and ask your Doctor for an RX for the equivalent of Levsin(Hyoscyamine) or Lomotil (Diphenoxylate with Atropine). Both are antispasmodic medications that help with urgency in use of a WC/Restroom/Bathroom. Lomotil is a controlled substance here in the US but many doctors will quickly write an RX if you tell them where you are traveling.
As others have said most of the problems people experience are from foreign flora not a harmful bacterial infection. Your body will adjust in time if affected at all.
Wash hands, use sealed bottled water & be careful with your food choices.