Which of the following is NOT listed as a treatment option for traveler's diarrhea in the source material?

• A. Metronidazole
• B. Loperamide
• C. Ciprofloxacin
• D. Bismuth subsalicylate

Answer: (A)

Traveler's diarrhea is treated with agents that target the bacteria most commonly causing it and with measures to rehydrate and reduce symptoms. Metronidazole focuses on anaerobic bacteria and certain parasites, not the typical enteric pathogens like ETEC and related bacteria that usually drive traveler's diarrhea. Because these pathogens are not reliably susceptible to metronidazole, it isn’t listed as a treatment option in the source material. In contrast, options that are listed—such as loperamide and bismuth subsalicylate for symptom relief, and antibiotics like ciprofloxacin for the infection—align with the pathogens involved and how they’re best treated.