Suggest Treatment For Loose Motions While Traveling

I am 74 years old male. Often I get loose motion if I travel outside home. Travelling is part of my profession. I take tinidazole TINIBA 500mg,with loperat twice a day and continue it for three days.
I become normal. But it happens once in three months. I consulted a gastroenterologist. He advises that I should take Norflox TZ twice a day and to continue it for five days. The problem with the Norflaxacin, I am sensitive multi antibiotic, a problem patient. If I get any antibiotic, immediately I swoon, and I am revived with intravenous drips, and hospitalization. I am hypertensive under control.
I take Olmozest AM. Kindly advise how best I can prevent attack of bacteria and amoeba. I take mineral water always, and my utensils are sterile at home. But outside home, I cannot help such care. Kindly advise.