Purpose: Apply the Enterobacteriaceae identification method for distinguishing Enterobacteriaceae strains, including Cronobacter spp. and close related non-Cronobacter genera in mixed samples.
Methods: A fusion-primer based method was developed, internally validated (validation was performed with 20 Enterobacteriaceae species and 19 mixtures) and adapted by SGS Molecular to become a beta version library preparation kit. The Cronobacter spp. study performed at Nestlé Research Center included 15 Cronobacter spp. isolated strains and 10 different mixtures of Cronobacter and non-Cronobacter spp. strains analised by triplicate. After preparation, libraries were sequenced using Ion torrent platform. Sequencing results were analyzed with a dedicated software developed by SGS Molecular.
Results: All the Enterobacteriaceae species tested during the method’s validation could be correctly identified. Considering Cronobacter spp. evaluation, all isolated strains were properly identified and in all mixtures Cronobacter spp. could be distinguished from non-Cronobacter spp. strains. With some few exceptions, the Enterobacteriaceae strains analyzed together with Cronobacter spp. were properly identified.
Significance: Although some improvements must be performed to this workflow, results obtained suggest that SGS Molecular’s kit for Enterobacteriaceae identification allows the distinction of species within this bacterial group, as well as the differentiation of Cronobacter spp. from non-Cronobacter spp. strains in mixed populations