Department of Food Science, Cornell University, Ithaca, New York 14853, USA.
J Food Prot. 2013 Jan;76(1):40-51. doi: 10.4315/0362-028X.JFP-11-546.
Foodborne pathogen isolate collections are important for the development of detection methods, for validation of intervention strategies, and to develop an understanding of pathogenesis and virulence. We have assembled a publicly available Cronobacter (formerly Enterobacter sakazakii) isolate set that consists of (i) 25 Cronobacter sakazakii isolates, (ii) two Cronobacter malonaticus isolates, (iii) one Cronobacter muytjensii isolate, which displays some atypical phenotypic characteristics, biochemical profiles, and colony color on selected differential media, and (iv) two nonclinical Enterobacter asburiae isolates, which show some phenotypic characteristics similar to those of Cronobacter spp. The set consists of human (n = 10), food (n = 11), and environmental (n = 9) isolates. Analysis of partial 16S rDNA sequence and seven-gene multilocus sequence typing data allowed for reliable identification of these isolates to species and identification of 14 isolates as sequence type 4, which had previously been shown to be the most common C. sakazakii sequence type associated with neonatal meningitis. Phenotypic characterization was carried out with API 20E and API 32E test strips and streaking on two selective chromogenic agars; isolates were also assessed for sorbitol fermentation and growth at 45°C. Although these strategies typically produced the same classification as sequence-based strategies, based on a panel of four biochemical tests, one C. sakazakii isolate yielded inconclusive data and one was classified as C. malonaticus. EcoRI automated ribotyping and pulsed-field gel electrophoresis (PFGE) with XbaI separated the set into 23 unique ribotypes and 30 unique PFGE types, respectively, indicating subtype diversity within the set. Subtype and source data for the collection are publicly available in the PathogenTracker database (www. pathogentracker. net), which allows for continuous updating of information on the set, including links to publications that include information on isolates from this collection.
食源性病原菌分离株集对于检测方法的开发、干预策略的验证以及对发病机制和毒力的理解非常重要。我们收集了一组公开可用的克罗诺杆菌（原称阪崎肠杆菌）分离株，其中包括：（i）25 株阪崎肠杆菌分离株，（ii）2 株克罗诺杆菌迟钝爱德华菌分离株，（iii）1 株克罗诺杆菌穆氏亚种分离株，其在一些选定的鉴别培养基上显示出一些非典型的表型特征、生化特征和菌落颜色，（iv）2 株非临床的阴沟肠杆菌分离株，其显示出一些与克罗诺杆菌属相似的表型特征。该分离株集包括人类（n=10）、食品（n=11）和环境（n=9）来源的分离株。部分 16S rDNA 序列和 7 基因多位点序列分型数据分析可对这些分离株进行准确的种属鉴定，其中 14 株鉴定为序列型 4，先前研究表明该序列型与新生儿脑膜炎最相关，是最常见的与阪崎肠杆菌相关的序列型。通过 API 20E 和 API 32E 测试条和两种选择性显色琼脂平板划线进行表型特征分析；还评估了分离株的山梨醇发酵和 45°C 生长能力。虽然这些策略通常与基于序列的策略产生相同的分类，但基于 4 种生化测试的组合，1 株阪崎肠杆菌分离株产生了不确定的数据，1 株被鉴定为克罗诺杆菌迟钝爱德华菌。EcoRI 自动化核糖体分型和 XbaI 脉冲场凝胶电泳（PFGE）将该分离株集分为 23 种独特的核糖体型和 30 种独特的 PFGE 型，表明该分离株集内存在亚型多样性。分离株的生态型和来源数据在 PathogenTracker 数据库（www.pathogentracker.net）中公开，可实现对分离株集信息的持续更新，包括指向包含该分离株集信息的出版物的链接。
