Isolation and identification of a Escherichia coli strain of mixed O serotypes in piglet.

A Gram-negative bacteria was isolated from the mesenteric lymph nodes of a dead weaning piglet.The bacterial strain was identified as a SLT-Ⅱe producing Escherichia coli with mixed O serotypes after morphological observation,biochemical identification,PCR detection of SLT-Ⅱe gene and identification of O serotype.The sequence of SLT-Ⅱe gene of isolated strain was identical to the published sequences in GenBank(AY368993).Injection mice with crude SLT-Ⅱe produced hind limb paralysis,death and gastrointestinal edema.