Aref Nasr-Eldin M, Abdel-Raheem Abdel-Raheem A, Kamaly Hanaa F, Hussien Soher Z
Department of Animal Medicine, Faculty of Veterinary Medicine, Assiut University, Assiut 71526, Egypt.
Animal Health Research Institute, Assuit, Egypt.
Open Vet J. 2018;8(4):351-359. doi: 10.4314/ovj.v8i4.1. Epub 2018 Oct 12.
The present study was carried out to characterize pathogenic in apparently healthy and diarrheic neonatal calves with special reference to the hybrid strains and evaluate their clinical and hematobiochemical consequences. One hundred and seventy calves (age 1-30 days) were divided into two groups: apparently healthy (n = 70) and diarrheic (n=100). Animals were subjected to thorough clinical, hematobiochemical and bacteriological examinations. Clinically, diarrheic calves showed various degree of diarrhea with the presence of cardinal signs of dehydration in moderate and severe cases. There was a significant increase (p<0.05) in the hemogram parameters with uremia and hyperkalemia in calves with severe diarrhea. The O-H serotyping of cultural and biochemically positive isolates identified 31 isolates belonging to 12 serotypes including O44:H18, O55:H7, O146:H21, O113:H4, O121:H7, O26:H11, O91:H21, O111:H2, O8, O127: H6, O86 and O128:H2. Molecular characterization of isolates on three toxin genes: heat-stable enterotoxin (, shiga toxin type 1 and 2 ( and revealed two well-known pathotypes (EPEC O44:H18, O55:H7, O146:H21, O113:H4, O121:H7 and EHEC O26:H11 O91:H21 O111:H2) with high frequency of enterohemorrhagic (EHEC). Molecular analysis also showed a number of isolates that carry and or and gene and belonged to O8, and O127:H6, O86 and O128:H2. These isolates were identified as hybrid strains (ETEC-STEC) and found in both apparently healthy and diarrheic calves. In conclusion, the present study identified high frequency of pathogenic in both apparently healthy and diarrheic calves. Serological and molecular analysis of isolates showed that high frequency of EHEC and presence of a new phenotype, STEC-ETEC hybrid, revealing their importance in the etiopathogenesis of diarrhea in calves and reinforcing the role of these animals as a reservoir of potentially pathogenic for humans.
本研究旨在对表面健康和腹泻的新生犊牛体内的致病性大肠杆菌进行特征描述，特别关注杂交菌株，并评估其临床和血液生化后果。170头犊牛（年龄1 - 30天）被分为两组：表面健康组（n = 70）和腹泻组（n = 100）。对动物进行了全面的临床、血液生化和细菌学检查。临床上，腹泻犊牛表现出不同程度的腹泻，中度和重度病例出现脱水的主要体征。重度腹泻犊牛的血常规参数、尿毒症和高钾血症显著增加（p<0.05）。对培养和生化检测呈阳性的分离株进行O - H血清分型，鉴定出31株分离株，属于12种血清型，包括O44:H18、O55:H7、O146:H21、O113:H4、O121:H7、O26:H11、O91:H21、O111:H2、O8、O127:H6、O86和O128:H2。对分离株的三种毒素基因：热稳定肠毒素（ST）、志贺毒素1型和2型（stx1和stx2）进行分子特征分析，揭示了两种著名的致病型（肠致病性大肠杆菌O44:H18、O55:H7、O146:H21、O113:H4、O121:H7和肠出血性大肠杆菌O26:H11、O91:H21、O111:H2），其中肠出血性大肠杆菌的频率较高。分子分析还显示，一些携带stx1和stx2或stx2和eae基因的分离株属于O8、O127:H6、O86和O128:H2。这些分离株被鉴定为杂交大肠杆菌菌株（产肠毒素大肠杆菌 - 肠出血性大肠杆菌），在表面健康和腹泻的犊牛中均有发现。总之，本研究发现表面健康和腹泻的犊牛体内致病性大肠杆菌的频率都很高。对大肠杆菌分离株的血清学和分子分析表明，肠出血性大肠杆菌的频率很高，并且存在一种新的表型，即产肠毒素大肠杆菌 - 肠出血性大肠杆菌杂交株，揭示了它们在犊牛腹泻病因学中的重要性，并强化了这些动物作为人类潜在致病性大肠杆菌储存宿主的作用。
