Characterization of the cryptic Escherichia lineages: rapid identification and prevalence
Characterization of the cryptic Escherichia lineages: rapid identification and prevalence
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DOI：
10.1111/j.1462-2920.2011.02519.x
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发表时间：
2011-09-01
影响因子：
5.1
通讯作者：
Denamur, Erick
中科院分区：
文献类型：
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作者：
Clermont, Olivier;Gordon, David M.;Denamur, Erick
菌株表型上与大肠杆菌不可区分，并且属于至少五个不同的隐蔽谱系，命名为大肠杆菌分支I至V，其在遗传上与大肠杆菌不同。大肠杆菌，但该属的成员最近已发现使用多位点序列分型（MLST）。关于这些菌株的流行病学数据非常少，因为MLST检测不适合大规模研究。在这项工作中，我们开发了一种快速PCR方法的基础上AES和chuA等位基因特异性扩增，分配一个神秘的血统成员的菌株。通过用这种方法筛选超过3500株菌株，我们表明，在人类粪便样本中不太可能检测到埃希氏菌的隐蔽谱系（2-3%的频率），甚至更不可能从肠外身体部位分离（< 1%的频率）。它们在动物粪便中的含量更高，从非人类哺乳动物的3-8%到鸟类的8-28%不等。总体而言，来自进化枝V的菌株是最丰富的，来自进化枝II的菌株非常罕见。这些结果表明，隐枝的成员不太可能对人类和健康有意义，但可能会影响'E。大肠杆菌作为水质指标。
Strains phenotypically indistinguishable from Escherichia coli and belonging to at least five distinct cryptic lineages, named Escherichia clades I to V, that are genetically divergent from E. coli yet members of the genus have been recently found using multi-locus sequence typing (MLST). Very few epidemiological data are available on these strains as their detection by MLST is not suitable for large-scale studies. In this work, we developed a rapid PCR method based on aes and chuA allele-specific amplifications that assigns a strain a cryptic lineage membership. By screening more than 3500 strains with this approach, we show that the cryptic lineages of Escherichia are unlikely to be detected in human faecal samples (2-3% frequency) and even less likely to be isolated from extra-intestinal body sites (< 1% frequency). They are more abundant in animal faeces ranging from 3-8% in non-human mammals to 8-28% in birds. Overall, the strains from the clade V are the most abundant and from the clade II very rare. These results suggest that members of the cryptic clades are unlikely to be of significance to human and health but may influence the use of 'E. coli' as an indicator of water quality.