Travelers' diarrhea: microbiologic bases for prevention and treatment.

The microbiology of travelers' diarrhea has become reasonably well defined, although new bacterial agents are probably yet to be described. The most common etiologic agent, enterotoxigenic Escherichia coli (ETEC), has been studied extensively and, because of the importance of this etiology, strategies for prevention and treatment of ETEC diarrhea with antimicrobial agents have been devised. The prevention of travelers' diarrhea by immunization will, to a large extent, depend on the development of vaccines against ETEC. Because the etiologic agents that cause travelers' diarrhea are the same ones (with the exception of rotavirus) that cause acute diarrhea in small children living in the developing world that tourists visit, any advances in prevention and treatment of diarrhea in travelers will be directly applicable to the worldwide problem of diarrhea in children, which is far more important on a global scale.