Genotypic and phenotypic characterisation of a collection of Cronobacter (Enterobacter sakazakii) isolates
Genotypic and phenotypic characterisation of a collection of Cronobacter (Enterobacter sakazakii) isolates
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DOI：
10.1016/j.ijfoodmicro.2010.01.045
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发表时间：
2010-04-30
影响因子：
5.4
通讯作者：
Besse, Nathalie Gnanou
中科院分区：
文献类型：
--
作者：
Miled-Bennour, Rabeb;Ells, Timothy C.;Besse, Nathalie Gnanou
坂崎肠杆菌是引起新生儿严重感染的病原菌，死亡率高。在许多情况下，婴儿配方奶粉（PIF）已被确定为感染源。最近，E.将坂崎氏菌归入新的属--Cronazakii。由于对这种病原体的了解仍然不完整，因此需要分子表征方案，以帮助流行病学调查和评估菌株变异性。本研究的目的是将联合收割机基因型（脉冲场凝胶电泳[PFGE]，16 S rRNA基因测序，和自动核糖体分型）方法与传统的表型生化方法，以表征收集从不同来源的克罗伊氏菌分离株。此外，通过估计25 ℃和37 ℃下各分离株在非选择性肉汤（BHI）中的生长速率，比较了相对生长动力学。根据生化试验结果，大多数分离株被鉴定为坂崎克罗伊氏菌。这似乎是最常见的物种分布在PIF生产工厂的环境中。此外，PFGE技术显示出非常高的区分能力，在150个克罗诺杆菌分离株中发现了61种不同的脉型。结合样品来源和脉冲类型的信息，64个分离物被认为是独特的菌株。虽然菌株的遗传分型数据清楚地将它们划分为与生化形态结果密切对应的簇，但并非没有差异，因为一些菌株没有按预测分组。重要的定量风险评估是这样一个事实，即尽管观察到的高遗传异质性，该集合，大多数克罗埃西亚菌株显示出相似的增长率，无论物种名称。皇冠版权所有（C）2010由爱思唯尔B. V.出版保留所有权利。
Enterobacter sakazakii has been identified as the causative agent of serious neonatal infections, associated with high mortality rate. In many cases, powdered infant formula (PIF) has been identified as the source of infection. Recently, E. sakazakii was proposed to be classified in a new genus, Cronobacter. Since knowledge on this pathogen is still incomplete, there is a need for molecular characterization schemes in order to help with epidemiological investigation and evaluate strain variability. The objectives of this study were to combine genotypic (pulsed-field gel electrophoresis [PFGE], 16S rRNA gene sequencing, and automated ribotyping) methods with traditional phenotypic biochemical methods to characterize a collection of Cronobacter isolates from various origins. In addition, the relative growth dynamics were compared by estimating the growth rates for each isolate in non-selective broth (BHI) at 25 degrees C and 37 degrees C. According to biochemical test profiles the majority of isolates were identified as Cronobacter sakazakii. which seemed to be the most common species distributed in the environment of PIF production plants. Furthermore, the PFGE technique displayed very high discriminatory power as 61 distinct pulsotypes were revealed among the 150 Cronobacter isolates. Combining information on sample origin and pulse type, 64 isolates were deemed as unique strains. Although genetic typing data for the strains clearly delineated them into clusters closely corresponding to biochemical speciation results, it was not without discrepancies as some strains did not group as predicted. Important for quantitative risk assessment is the fact that despite the high genetic heterogeneity observed for this collection, most Cronobacter strains displayed similar growth rates irrespective of species designation. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.