Ganaba R, Bigras-Poulin M, Fairbrother J M, Bélanger D
Département de pathologie et microbiologie, Faculté de Médecine vétérinaire, Université de Montréal, Québec.
Can J Vet Res. 1995 Jan;59(1):20-5.
The objectives of this study were: (i) to investigate the prevalence of Escherichia coli producing F5 (K99), F41, or F165 fimbriae and STa enterotoxin; (ii) to determine serum antibody levels against these fimbriae; (iii) and to examine the association between bacteriological and serological results and the presence of diarrhea, in beef calves from northwestern Quebec. A total of 373 live three to four week old calves and 27 dead calves were sampled between January and March 1991. No isolates positive for F5 were detected in live calves, and only one E. coli producing STa and F41 was isolated. Escherichia coli producing F41-like surface antigens or F165 fimbriae were isolated from 17.43% and 5.63% of live calves, respectively. Antibodies against F5, F41 and F165 were low. Escherichia coli isolates positive for F41-like surface antigen were most often observed in calves born between January and March. No association was found between bacteriological and serological findings, nor between these findings and diarrhea. Calves born from dams vaccinated against E. coli had higher median antibody levels than those born from unvaccinated dams. No E. coli positive for F5 or F41 fimbriae were isolated from dead calves. Escherichia coli with F41-like surface antigen or F165 were found in 55.56% and 11.11% of ileal samples; 4% and 16% of cecal samples, and 0% and 7.4% of colon samples, respectively. Escherichia coli positive for F41-like surface antigen were detected significantly more frequently in the ileum (chi (2)2df = 31.01, p < 0.001).
（i）调查产F5（K99）、F41或F165菌毛以及STa肠毒素的大肠杆菌的流行情况；（ii）测定针对这些菌毛的血清抗体水平；（iii）检查魁北克西北部肉牛犊的细菌学和血清学结果与腹泻存在之间的关联。1991年1月至3月期间，共采集了373头3至4周龄的活犊牛和27头死犊牛的样本。在活犊牛中未检测到F5阳性分离株，仅分离出一株产STa和F41的大肠杆菌。分别从17.43%和5.63%的活犊牛中分离出产F41样表面抗原或F165菌毛的大肠杆菌。针对F5、F41和F165的抗体水平较低。F41样表面抗原阳性的大肠杆菌分离株最常见于1月至3月出生的犊牛。在细菌学和血清学结果之间未发现关联，这些结果与腹泻之间也未发现关联。接种过大肠杆菌疫苗的母牛所生的犊牛，其抗体水平中位数高于未接种疫苗的母牛所生的犊牛。在死犊牛中未分离出F5或F41菌毛阳性的大肠杆菌。F41样表面抗原或F165的大肠杆菌分别在55.56%的回肠样本、4%的盲肠样本和0%的结肠样本中被发现；在11.11%的回肠样本、16%的盲肠样本和7.4%的结肠样本中被发现。F41样表面抗原阳性的大肠杆菌在回肠中被检测到的频率显著更高（卡方检验（2）2自由度 = 31.01，p < 0.001）。
