Prevention and treatment of traveler's diarrhea. Focus on antimicrobial agents

Diarrhea, mostly due to bacterial infection of the gut, is the most frequent health complaint in the international traveler, affecting 20-70% of the traveling population depending on the destination and other factors. It is usually benign and self-limiting in nature, but symptoms may occasionally be distressing causing modifications of normal activities and sometimes confinement to bed or hospitalization. Prevention of traveler's diarrhea should ideally be based on dietary restrictions, but experience shows that this target is extremely difficult to achieve. Antibiotic chemoprophylaxis should be restricted to selected groups of travelers at risk of severe complications of diarrhea or when diarrhea-driven alterations of planned activities are highly undesirable (critical trips). The effectiveness of alternative prophylactic approaches, such as vaccination or the use of probiotics, still awaits confirmation. Treatment of mild diarrheal cases without intestinal symptoms may be limited to rehydration with or without antimotility agents. When antibiotic therapy is considered, non-absorbable antibiotics, such as rifaximin, may be considered a valid alternative to systemic antibiotics to treat uncomplicated cases, leaving fluoroquinolones and/or azithromycin for use in more severe cases or when invasive pathogens are suspected. Indeed, therapeutic use of doxycycline and trimethoprim-sulfamethoxazole (TMP-SMX) is limited by widespread resistance of many enteropathogens. The addition of loperamide or other antimotility agents usually provides symptom relief and further shortens the duration of illness and may be therefore safely adopted in the healthy adult unless dysentery is present.