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首页> 外文期刊>Tropical Animal Health and Production >Molecular characterization of pathogenicEscherichia coliisolated from diarrheic and in-contact cattle and buffalo calves
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Molecular characterization of pathogenicEscherichia coliisolated from diarrheic and in-contact cattle and buffalo calves

机译：来自腹泻和牛犊的肺炎菌和水牛犊的分子表征Coliisolated

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Escherichia colifield isolates from calves were characterized and categorized into the most significant diarrheagenic pathotypes using polymerase chain reaction (PCR) assays with different specific primers. The used PCR systems were designed to detect sequences representing the group-specific virulence genes encoding fimbriaef5(K99), Shiga toxins (stx(1)andstx(2)), heat-stable enterotoxins (st), heat-labile enterotoxins (lt), intimin (eae), hemolysin (hylA), and EAEC heat-stable enterotoxin (astA). In the present work, a total of 150E. colifield isolates were recovered from 150 fecal swabs collected from 100 diarrheic and 50 apparently healthy in-contact cattle and buffalo calves under 3 months old. Out of these 150 isolatedE. coli, 106 isolates from 77 diarrheic and 29 in-contact calves harbored one or more of the investigated virulence genes. The pathotyping of the isolates could classify them into shigatoxigenicE. coli(STEC), enteropathogenicE. coli(EPEC), enterotoxigenicE. coli(ETEC), and enteroaggregativeE. coli(EAEC) with a 30.7, 2.7, 12.7, and 7.3% distribution, respectively. Meanwhile, the detection rates off5,stx(1),stx(2),st,lt,eae,hylA, andastAgenes were 17.3, 27.3, 6.7, 10, 37.3, 17.7, 9.3, and 20.7%, respectively. These virulence genes were found either single or in different combinations, such asstx/eae,stx/st/f5,eae/st/f5, orst/lt/f5. Four attaching-effacing shigatoxigenicE. coliisolates (AE-STEC) harboringstx/eaewere retrieved from diarrheic calves. Although none of thestx-oreae-positive isolates was verified as O157:H7, STEC isolates detected in apparently healthy calves have potential pathogenicity to humans highlighting their zoonotic importance as reservoirs. Atypical combinations of ETEC/STEC and ETEC/EPEC were also detected in percentages of 14.7 and 2.7%, respectively. Most of these atypical combinations were found more in buffalo calves than in cattle calves. While STEC and EPEC isolates were detected more in cattle calves than in buffalo calves, ETEC isolates were the same in the two species. The pathogenicE. coliinfection in calves was recorded to be higher in the first weeks of life with the largest numbers of virulence factor-positive isolates detected at the age of 4 weeks. Histopathological examination of five intestinal samples collected from four dead buffalo calves revealed typical attaching and effacing (AE) lesion which was correlated with the presence of intimin encoding virulence gene (eae). Other lesions characterized by hemorrhagic enteritis, shortening and fusion of intestinal villi and desquamation of the lining epithelium of intestinal mucosa had also been detected.
机译：来自小牛的大肠杆菌分离株分离，并分为使用具有不同特异性引物的聚合酶链式反应（PCR）测定的最重要的腹泻病型。设计了二手PCR系统以检测代表编码Fimbriaf5（K99）的群体特异性毒力基因的序列（STX（1）和Stx（2）），热稳定的肠毒素（ST），热稳定肠毒素（LT） ，内菊酯（EAE），溶血素（Hyla）和EAEC热稳定肠毒素（ASTA）。在目前的工作中，总共150E。从100位腹泻收集的150个粪便拭子中回收了大肠杆菌分离株，并且在3个月之下的50个明显的健康的接触牛和水牛犊处。其中150个被隔离。大肠杆菌，106个腹泻的分离物和29个接触犊牛患有一个或多个研究的毒力基因。分离物的病理分型可以将它们分为恶毒素。 Coli（stec），肠病理学。 Coli（EPEC），肠毒素。大肠杆菌（ETEC）和肠溶精神。 Coli（EAEC）分别为30.7,2.7,12.7和7.3％分布。同时，检测速率OFF5，STX（1），STX（2），ST，LT，EAE，Hyla，Andastagens分别为17.3,27.3,6.7,10,37.3,17.7,9.3和20.7％。这些毒力基因被发现单个或不同组合，例如诸如斯克斯/ EAE，STX / ST / F5，EAE / ST / F5，ORST / LT / F5。四个附着的infacing shigatoxigenice。 Coliisolates（AE-STEC）从腹泻小牛中检索窝藏出来/ EAWERE。虽然没有鉴于O157：H7，但在明显健康的小腿中检测到的STEC分离物对人类的潜在致病性，但对人类的潜在致病性突出，突出了它们作为储层的人畜共位痛。 ETEC / STEC和ETEC / EPEC的非典型组合也分别以14.7和2.7％的百分比检测。大多数这些非典型组合在布法罗犊牛比牛犊中的比例更多地发现了更多。虽然STEC和EPEC分离物在牛犊中检测到比水牛小牛更多，但两种物种中的ETEC分离物相同。病因研究。犊牛的Coliinfection在第一周的生命中被记录为更高的生命，其在4周龄在4周龄的毒力因子阳性分离物数量最多。从四个死水牛犊机收集的五个肠样品的组织病理学检查揭示了典型的附着和缺陷（AE）病变，其与编码毒力基因（EAE）的存在相关。还检测了其他病变，其特征在于出血肠炎，速度缺血和肠道上皮脱落的裂缝和肠粘膜脱落的融合。

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