PROLIFERATIVE ENTEROCOLITIS ASSOCIATED WITH DUAL INFECTION WITH ENTEROPATHOGENIC ESCHERICHIA-COLI AND LAWSONIA-INTRACELLULARIS IN RABBITS

Both enteropathogenic Escherichia coli (EPEC) and an obligate intracel lular bacterium, previously referred to as an intracellular Campylobac ter-like organism and now designated Lawsonia intracellularis, have be en reported as causes of enterocolitis in rabbits. An outbreak of ente rocolitis in a group of rabbits, characterized by an unusually high ra te of mortality, was found to be associated with dual infection with E PEC and L. intracellularis. The EPEC strain was found to have eaeA gen e homology but was negative for afrA homology, The absence of the afrA gene, which encodes the structural subunit for the AF/R1 pilus, indic ates that this rabbit EPEC strain is distinct from the prototypic RDEC -1 strain. This finding suggests that rabbit EPEC strains widely repor ted in Western Europe, which lack AF/R1 pill, are also present in rabb its in the United States. Dual infection with these two pathogens in r abbits has not been previously reported and may have contributed to th e unusually high mortality observed in this outbreak.