Bacterial Diarrhea

Foodborne bacterial diarrhea is an emerging health threat that is attributable to the increased consumption of fresh vegetables and fruits, the challenges associated with producing large quantities of inexpensive foods, the increasing importation of foods from developing regions, and the growing pattern of consumption of foods in public restaurants.1 Of the more than 5.2 million cases of bacterial diarrhea that occur each year in the United States, 80% are a result of foodborne transmission.2 Personto-person spread occurs if only a small amount of a pathogen is required for infection; these pathogens include shigella, Shiga toxin–producing Escherichia coli, and protozoal and viral agents. Bacterial enteropathogens lead to an estimated 46,000 hospitalizations and 1500 deaths each year in the United States. The four most commonly reported bacterial enteropathogens in the United States — campylobacter, nontyphoid salmonella, Shiga toxin–producing E. coli, and shigella — are associated with an estimated cost of $7 billion annually.3 The first three of these organisms are spread to humans from animal reservoirs and are currently threatening our food supply.1 The highest incidence of campylobacter and salmonella infection occurs among infants, presumably because of cross-contamination in the household and the lower number of organisms required to cause clinical infection in infants than in older children and adults. Table 1 lists the projected incidence of illness caused by bacterial enteropathogens in the United States and the typical clinical manifestations of these illnesses. In addition to these organisms, other bacterial enteropathogens cause variable numbers of cases of diarrhea. Aeromonas species occur worldwide but are particularly important in tropical regions; they cause acute or persistent diarrhea or dysenteric diarrhea (passage of grossly bloody stools). Plesiomonas shigelloides is a cause of acute diarrhea associated with seafood consumption and international travel. Enterotoxigenic E. coli is a growing cause of foodborne diarrhea, and enteroaggregative E. coli is an inadequately studied but potentially important cause of endemic diarrhea in children in the United States. Although bacterial enteropathogens are of the greatest importance for children living in the developing world, this article concentrates on bacterial diarrhea in the United States, which is similar to that in other industrialized regions. A previous review provides additional information about infectious diarrhea.6 This Journal feature begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines, when they exist. The article ends with the author’s clinical recommendations.