title: Genotypic and phenotypic characteristics of Cronobacter species, with particular attention to the newly reclassified species Cronobacter helveticus, Cronobacter pulveris, and Cronobacter zurichensis.
abstract: In 2013, Enterobacter helveticus, Enterobacter pulveris and Enterobacter turicensis, were reclassified as Cronobacter helveticus, Cronobacter pulveris and Cronobacter zurichensis, respectively. Previously these species had been used as negative controls for some Cronobacter detection assays. This study examined cultural, biochemical and molecular Cronobacter detection and identification assays, with emphasis on the new species. Additionally, 32 Cronobacter genomes were examined for the presence of PCR target genes using the BLAST function of the online Cronobacter PubMLST facility. The results of the cultural methods varied and no single medium was able to correctly detect all Cronobacter spp. Since the supporting databases have not been updated to include the Cronobacter genus, Enterobacter sakazakii was returned for four strains of the newly reclassified species with ID32E and none with API 20E. PCR probes targeting rpoB and ompA could not correctly identify the new Cronobacter spp., due to primer specificity or absent target genes. As neonates have been identified as a high-risk group for infection, international standards require the absence of all Cronobacter species in powdered infant formula. However, many conventional detection methods cannot correctly identify the newly recognized species. Conversely, DNA sequence-based methods can adapt to taxonomic revisions and will likely become more common.
authors.affiliation: Pathogen Research Group, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.
authors.forename: E E
authors.initials: EE
authors.lastname: Jackson
authors.affiliation: Pathogen Research Group, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.
authors.forename: H
authors.initials: H
authors.lastname: Sonbol
authors.affiliation: Pathogen Research Group, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.
authors.forename: N
authors.initials: N
authors.lastname: Masood
authors.affiliation: Pathogen Research Group, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK. Electronic address: stephen.forsythe@ntu.ac.uk.
authors.forename: S J
authors.initials: SJ
authors.lastname: Forsythe
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D059126:Cronobacter / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D005516:Food Microbiology; D005838:Genotype; D006801:Humans; D010641:Phenotype
chemical_list: D001426:Bacterial Proteins
keywords: Cronobacter; Detection methods; Identification methods