Demonstration of enterotoxigenic Escherichia coli in diarrheic broiler chicks.

An investigation was made to survey the possible presence of enterotoxigenic Escherichia coli (ETEC) in the stools of diarrheal chicks. We analyzed two outbreaks of diarrhea in broiler chicks at two independent farms in the Philippines, from which no pathogens other than Escherichia coli were found. In one outbreak at Farm #1, all 42 isolates produced heat-labile enterotoxin (LT), with 3 of these isolates also producing heat-stable enterotoxin (ST). The O serotypes of 15 strains tested randomly could not be identified as any known serotype (0-antigen; 1-170). In another outbreak at Farm #2, 7 out of 52 isolates produced only LT, their subtypes being identified as O-149 or O-8, common serotypes in pig ETEC. Strains from Farm #1 did not produce any pili usually found in human ETEC. We believe this to be the first isolation of ETEC from diarrheal chicks.