Blanco J, González E A, García S, Blanco M, Regueiro B, Bernárdez I
Departmento de Microbiología y Parasitología, Facultades de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain.
Vet Microbiol. 1988 Dec;18(3-4):297-311. doi: 10.1016/0378-1135(88)90095-8.
A total of 289 Escherichia coli colonies isolated from 78 diarrhoeic calves were studied for production of heat-labile (LT) and heat-stable (STa) enterotoxins, verotoxin (VT), cytotoxic necrotizing factor (CNF) and K99 antigen, and they were serotyped. Production of STa was detected in a single strain possessing both K99 and F41 antigens; the serotype was 09:K (A) 35. LT-producing strains were not detected. From 16 (20.5%) calves, 51 VT-producing colonies of E. coli were isolated. Production of the necrotic factor was detected in 33 E. coli colonies isolated from 14 (17.9%) calves. Serotype was a useful marker for production of VT and CNF. Among the 51 VT-producing colonies, 24 were untypable and the remainder belonged to serotypes O2:K?, O103:K--, O104:K?, O128:K?, O153:K-- and O157:K--:H7. Four of the 33 CNF-producing colonies were untypable and the majority of the remaining colonies belonged to serotypes O15:K14, O78:(K80), O123:K-- and O139:K--. Both VT and CNF were lethal for mice, but only CNF showed necrotizing reaction in rabbit skin. Our results indicate that VT-producing and CNF-producing E. coli strains are frequently isolated from diarrhoeic calves and that according to the serotypes exhibited, some of them might be considered potential pathogens for humans. The role of VT-producing and CNF-producing strains in calf diarhoea remains to be established.
对从78头腹泻犊牛中分离出的289个大肠杆菌菌落进行了研究，检测其热不稳定（LT）和热稳定（STa）肠毒素、维罗毒素（VT）、细胞毒性坏死因子（CNF）及K99抗原的产生情况，并对其进行血清分型。在一株同时具有K99和F41抗原的菌株中检测到了STa的产生；血清型为09:K（A）35。未检测到产LT的菌株。从16头（20.5%）犊牛中分离出51个产VT的大肠杆菌菌落。在从14头（17.9%）犊牛中分离出的33个大肠杆菌菌落中检测到了坏死因子的产生。血清型是VT和CNF产生的一个有用标志物。在51个产VT的菌落中，24个无法分型，其余的属于血清型O2:K？、O103:K--、O104:K？、O128:K？、O153:K--和O157:K--:H7。33个产CNF的菌落中有4个无法分型，其余大多数菌落属于血清型O15:K14、O78:（K80）、O123:K--和O139:K--。VT和CNF对小鼠均有致死性，但只有CNF在兔皮上表现出坏死反应。我们的结果表明，产VT和产CNF的大肠杆菌菌株经常从腹泻犊牛中分离出来，根据所表现出的血清型，其中一些可能被认为是人类的潜在病原体。产VT和产CNF菌株在犊牛腹泻中的作用仍有待确定。
