Sanz M E, Viñas M R, Parma A E
Animal Health Department, Faculty of Veterinary, University of the Centre PBA, Tandil, Argentina.
Eur J Epidemiol. 1998 Jun;14(4):399-403. doi: 10.1023/a:1007427925583.
Faecal swabs obtained from 126 calves and 118 cows in Argentina were investigated for the presence of verotoxin-producing Escherichia coli (VTEC). VTEC strains were recovered from 10 (23%) of 43 calves with diarrhoea, from 24 (29%) of 83 healthy calves, from 40 (44%) of 91 healthy cows waiting at the slaughterhouse, and from 6 (22%) of 27 healthy grazing cattle. PCR showed that 21 (9%) of animals carried VT1+ strains, 49 (20%) VT2+ strains and 10 (4%) VT1+ VT2+ strains. VT1+ strains predominated among calves (16% versus 0.8%; p < 0.001). The presence of eae gene was significantly more frequent among VTEC strains isolated from calves (78%; 46/59) than from cows (2%; 1/65) (p < 0.001). Furthermore, eae gene was more prevalent in VT1+ strains (97%; 32/33) than in VT2+ strains (14%; 10/70) (p < 0.001) and in VT1+ VT2+ strains (24%; 5/21) (p < 0.001). Sorbitol negative high virulent strains serogroups O157 were not detected. This study indicates that cattle are a reservoir of VTEC strains, and that eae gene is associated with VT1+ strains that are predominating among young animals. Fortunately, only adult animals are taken to the slaughterhouse, among which VTEC strains negative for eae gene are predominating.
对从阿根廷的126头犊牛和118头母牛采集的粪便拭子进行了产志贺毒素大肠杆菌（VTEC）检测。从43头发腹泻的犊牛中的10头（23%）、83头健康犊牛中的24头（29%）、91头在屠宰场等待的健康母牛中的40头（44%）以及27头健康放牧牛中的6头（22%）中分离出了VTEC菌株。聚合酶链反应（PCR）显示，21头（9%）动物携带VT1+菌株，49头（20%）携带VT2+菌株，10头（4%）携带VT1+VT2+菌株。VT1+菌株在犊牛中占主导（16%对0.8%；p<0.001）。从犊牛分离出的VTEC菌株中eae基因的存在频率（78%；46/59）显著高于从母牛分离出的菌株（2%；1/65）（p<0.001）。此外，eae基因在VT1+菌株中（97%；32/33）比在VT2+菌株中（14%；10/70）更普遍（p<0.001），在VT1+VT2+菌株中（24%；5/21）也更普遍（p<0.001）。未检测到山梨醇阴性的高毒力菌株血清型O157。这项研究表明，牛是VTEC菌株的储存宿主，并且eae基因与在幼龄动物中占主导的VT1+菌株相关。幸运的是，只有成年动物被送去屠宰，其中eae基因阴性的VTEC菌株占主导。
