Abstract. In an outbreak of gastroenteritis in December 2009, in Mandera, Kenya, Escherichia coli O-nontypable (ONT) strain was isolated from stool specimens of patients (18/24, 75%). The E. coli ONT organisms could not be assigned to any of the recognized diarrheagenic groups of E. coli. However, they possessed the enteroaggregative E. coli heat-stable enterotoxin-1 gene. The cell-free culture filtrates of the E. coli ONT strain isolated from the outbreak cases induced considerable amount of fluid accumulation in suckling mouse intestine, indicating production of an enterotoxic factor(s). These results identify E. coli that did not have any diarrheagenic characteristics except astA as the etiological agent of the diarrheal outbreak in Mandera. It is however considered necessary to characterize the fluid accumulation factor(s) to determine whether any novel toxins were responsible for the fluid accumulation. Moreover, it is important to study dissemination of strains producing the enterotoxic factor(s) to assess their public health significance distribution in the environment.

Enterotoxigenic E. coli (ETEC) is the major cause of diarrhoea in neonatal animals. This study determined the prevalence, serological diversity, virulence gene profile and in-vitro antibiogram of ETEC isolates from diarrhoeic faeces of calves and lambs. The prevalence rate of ETEC in lambs was recorded 18.46 % with O8 as predominant serotype. However, in calves the prevalence rate was recorded 8.57 % with O15 and O26 as predominant serotypes. The antibiogram screening showed differential susceptibility pattern among ETEC isolates with highest resistance to ampicillin and highest sensitivity to enrofloxacin. In the present study, for the first time it was reported that the diarrhoea in calves and lambs occur due to virulent gene est not due to elt gene, which was absent in all the isolates.