A Naturally Occurring Enterotyphlocolitis Associated with Dual Infection by Clostridium piliforme and Enteropathogenic Attaching and Effacing Escherichia coli in Syrian Hamsters

Three outbred weanling Syrian hamsters (Mesocricetus auratus) were submitted for necropsy after developing variably severe diarrhea and depression or dying unexpectedly shortly after shipping to a commercial pet store. Grossly, the three weanlings had thin-walled intestines that were distended with excessive amounts of turbid, yellowish-green fluid contents and friable mucosa, particularly in the ileum and cecum. Silver stain highlighted intralesional “stacks” of rod-shaped filamentous bacteria characteristic of Tyzzer’s disease in both of the small and large intestines of all three animals. Additionally, the liver of one weanling No.1 contained multifocal pinpoint foci of necrosis throughout the hepatic parenchyma and milder necrotizing lesions in the myocardium. In the intestines of the three weanlings, colonies of gram negative plump bacilli scalloped the apical surface of ileal, cecal and colonic enterocytes containing Clostridium piliforme (C. piliforme) filamentous bacilli in their cytoplasm. Samples of fresh intestines and feces from the three weanlings plus the liver from the weanling #1 demonstrated a 270-bp band specific to C. piliforme. Another 425-bp band specific to attaching and effacing Escherichia coli (AEEC) was identified in the intestines of the three hamsters. The PCR products were sequenced using 16S ribosomal ribonucleic acid (rRNA) gene based primers revealing 98% sequence alignment and homology with sequences specific to C. piliforme. This article represents the first published cases of enterotyphlocolitis associated with dual natural infection by AEEC and C. piliforme.