Prevention and treatment of traveler's diarrhea.

Common pathogens in traveler's diarrhea include enterotoxigenic Escherichia coli, Campylobacter, Shigella, Salmonella, Yersinia and many other species. Viruses and protozoa are the cause in many cases. Fortunately, traveler's diarrhea can usually be avoided by carefully selecting foods and beverages. Although drug prophylaxis is now discouraged, treatment with loperamide (in the absence of dysentery) and a fluoroquinolone, such as ciprofloxacin (500 mg twice daily for one to three days), is usually safe and effective in adults with traveler's diarrhea. Trimethoprim-sulfamethoxazole and doxycycline are alternatives, but resistance increasingly limits their usefulness. Antibiotic treatment is best reserved for cases that fail to quickly respond to loperamide. Antibiotic resistance is now widespread. Nonabsorbable antibiotics, immunoprophylaxis with vaccines and biotherapeutic microbes that inhibit pathogen infection may eventually supplant antibiotic treatment. In the meantime, azithromycin and new fluoroquinolones show promise as possible replacements for the older agents. Ultimately, the best solution is improvements in sanitary engineering and the development of safe water supplies.