A case of EHEC O157 infection showing hemorrhagic enteritis among beef cattle - Kanagawa
(IASR 2000; 21: 96-97)

Cattle are known reservoirs for enterohemorrhagic Escherichia coli (EHEC) O157, and it is believed that EHEC O157 is not pathogenic in cattle. However, we report here a beef cattle showing hemorrhagic enteritis associated with EHEC O157 and Coccidioides (Eimeria) infections.

The case cattle was a castrated 2-year-old F1 (by a Holstein mother and a black hair Japanese cattle father) from Kanagawa Prefecture. The cattle had developed diarrhea 4-5 days before an auction sale. The cattle was not examined by a veterinarian, but the symptom was reported to a slaughter center when the cattle was shipped.

The cattle was as examined before culling and was found to be dulland dehydrated; its anus was spoiled with bloody diarrhea. The body temperature was 37.9C. Blood chemistry revealed that BUN 170mg/dl, creatinine 22.1mg/dl, RBC 12.49X10⁶ /mm³, WBC 2,850 /mm³, and Ht 55%. Uremia and dehydration were suspected. The o-tolidine and guaiac test for blood in stool were positive.

Autopsy revealed mild bleeding of the gut mucosa, but no obvious pathological changes. Stool in the rectum was red-to-brown color with stimulus foul smelling. Strong smelling of urine was observed in the kidneys. Small stones were seen in the bladder with extensive and strong bleeding and edema.

Pathological examination revealed mild catarrhal enteritis and infection of Coccidioides with micro-blooding predominantly in the lamina propia. Hematoxylin-eosin stain did not reveal attaching and effacing (AE) lesion clearly. Adhesion of EHEC O157 to the epithelium resembling AE was observed by immunohistological examination using anti-O157 serum. In the kidney, glomeruli were slightly swollen, and the renal tubular epithelium showed a partially hydrops; however, these changes were less pronounced than those seen in human hemolytic uremic syndrome (HUS).

EHEC O157 was isolated from stool specimens in a maximum concentration of 4X10⁷ CFU/g. EHEC O157:H7 amounted to approximately 30-40% of E. coli colonies grown on selection agar such as Sorbitol MacConkey, and almost all were EHEC O157:H7 on CT-SMAC agar. Isolated strains were MUG (-) and sorbitol (-). Production of Stx2 was confirmed by reversed passive latex agglutination (RPLA). stx2 and eaeA genes were detected by polymerase chain reaction (PCR). With enzyme-linked immunosorbent assay (ELISA) Stx toxin was detected from stool, but not from serum or ascites. When Stx was inoculated with cells, its virulence was observed against Vero cell. No viruses were isolated from stool specimens.

Previously, several investigations reported that few percents of cows shed EHEC O157 with stool in concentrations <100 CFU/g, and those cows did not have gastrointestinal symptoms. Clinical symptoms, autopsy results, including immunohistological findings, however, suggest that the cow described here developed illness due to EHEC O157 infection. The question whether EHEC was the only agent responsible for the development of the present illness needs to be discussed, because the cow also was infected with Coccidioides and pathological findings due to EHEC O157 infection were limited. Although a renal disorders due to Stx were suspected, because the cow presented uremia, none of the pathological findings usually present in human HUS were observed.

This case raises concerns about animal hygiene. Because the case cow developed uremia, it was abandoned in accordance with the slaughter house law. In order to prevent secondary infection, bacterial examinations were conducted in the slaughterhouse, and the facility was disinfected. Information was reported to relevant public health and animal health authorities, and a health evaluation of the cow breeder, his family, cows on the farm was conducted, and environmental samples from water and compost were obtained. The breeder and his family were not infected. However, EHEC O157 was isolated from 6 of the 41 cows on the farm. One isolate from the case cow and 3 isolates from healthy cows showed an identical XbaI fragment pattern when compared with pulsed-field gel electrophoresis (PFGE).

Reported by Shouhei Kushima, Noriyuki Takahashi, Jun Gomi, and Yukiya Fukuma, Meat Inspection Station, Kanagawa Prefectural Government; Dept. of Bacteriology and Pathology, Kanagawa Prefectural Public Health Laboratory, Jun Terajima and Haruo Watanabe, National Institute of Infectious Diseases.

Correspondence: Meat Inspection Station, Kanagawa Prefectural Government;
E-mail: shokuken.1572@pref.kanagawa.jp

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