Prevalence, structure and expression of urease genes in Shiga toxin-producing Escherichia coli from humans and the environment.
Prevalence, structure and expression of urease genes in Shiga toxin-producing Escherichia coli from humans and the environment.
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DOI：
10.1016/j.ijheh.2006.06.003
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发表时间：
2006-11
影响因子：
6
通讯作者：
D. Orth;K. Grif;M. Dierich;R. Würzner
中科院分区：
文献类型：
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作者：
D. Orth;K. Grif;M. Dierich;R. Würzner
在大肠杆菌中，ure基因簇的一个组成部分。大肠杆菌中，ureC编码尿素酶的一个亚基。本文对202株产滋贺毒素大肠杆菌的ureC分布进行了研究。大肠杆菌（STEC）菌株来自奥地利，属于61种不同的血清型。这些菌株来源于人（n=150）、动物（n=38）和食物（n=14）。72株E.大肠杆菌O 157：H7和O 157：NM（非运动型）菌株以及血清型O26：H11/NM、O 111：H8/NM和O 145：NM的所有29株菌株。相比之下，8株产乙醇E. coliO 157：NM为ureC阳性。在携带eae的STEC中，ureC的发生率（113/132; 85.6%）显著高于eae阴性STEC菌株（4/70; 5.7%; p<0.0001）。202株尿素酶阳性菌株中仅有4株（2%）表达尿素酶活性，占尿素酶阳性菌株的3.4%。尿素酶表达与分离株来源（人与动物）之间无显著相关性（p=0.56）。来自10种不同血清型STEC中ure簇的所有7个基因的PCR扩增子的核苷酸序列分析显示出高度的同源性（1099%），表明最近获得的不一定表达的ure基因。
A component of the ure gene cluster in E. coli, ureC, encodes a subunit of urease. We have investigated the distribution of ureC in 202 Shiga toxin-producing E. coli (STEC) strains from Austria belonging to 61 different serotypes. These strains were of human (n=150), animal (n=38), and food (n=14) origin. ureC was present in all 72 E. coli O157:H7 and O157:NM (non-motile) strains, as well as in all 29 strains of serotypes O26:H11/NM, O111:H8/NM and O145:NM. In contrast, none of eight sorbitol-fermenting E. coli O157:NM were ureC-positive. ureC occurred significantly more frequently among STEC that carry eae (113 of 132; 85.6%) than among eae-negative STEC strains (four of 70; 5.7%; p<0.0001). However, only 4 (2%) of the 202 strains (3.4% of ureC positive strains) expressed urease activity. There was no significant association (p=0.56) between urease expression and the source of the isolates (humans vs. animals). Nucleotide sequence analysis of PCR amplicons derived from all seven genes of the ure cluster in STEC of 10 different serotypes demonstrated a high degree of homology (⩾99%), indicating a recent acquisition of not necessarily expressed ure genes.