Traveler's diarrhea at sea: Three outbreaks of waterborne enterotoxigenic Escherichia coli on cruise ships

Enterotoxigenic Escherichia coli (ETEC) has become the leading bacterial ca use of gastroenteritis outbreaks on cruise ships. Investigation of recent o utbreaks of ETEC gastroenteritis on 3 cruise ships indicated that all were associated with consuming beverages with ice cubes on board the ship (relat ive risk [RR], 1.4, 95% confidence interval [CI], 1.0-1.9, P = .02; RR, 1.9 , 95% CI, 1.3-2.9, P < .001; and RR, 1.3, 95% CI, 1.0-1.6, P < .01), and 2 were associated with drinking unbottled water (RR, 2.7, 95% CI, 1.8-4.1, P < .001; RR, 1.7, 95% CI, 1.3-2.3, P < .001). Multiple ETEC serotypes were d etected in patients' stool specimens in each of the 3 outbreaks, and 12 (38 %) of 32 isolates were resistant to greater than or equal to 3 antimicrobia l agents. ETEC appears to be emerging as a waterborne pathogen on cruise sh ips. Water bunkered in overseas ports was the likely source of ETEC infecti on in these outbreaks. To ensure passenger safety, cruise ships that take o n water in foreign ports must ensure that water treatment and monitoring sy stems function properly.