Enterobacter sakazakii is an opportunistic pathogen that can cause infections in neonates. This study further clarifies the taxonomy of isolates described as E. sakazakii and completes the description of the proposed reclassification of these organisms as novel species and subspecies within a proposed novel genus, Cronobacter. The species was first defined in 1980, however recent polyphasic taxonomic analysis has determined that this group of organisms consists of several genomospecies. In this study the phenotypic descriptions of the proposed novel species are expanded using Biotype 100 and Biolog Phenotype MicroArray™. Further DNA-DNA hybridization experiments showed that malonate positive strains within the C. sakazakii genomospecies represent a distinct species not a subspecies. DNA-DNA hybridizations also determined that phenotypically different strains within proposed Cronobacter dublinensis sp. nov. belong to the same species and can be considered novel subspecies.
Based on these analyses the following alternative classifications are proposed; Cronobacter sakazakii gen. nov. comb. nov., type strain ATCC 29544T (=NCTC 11467T); C. malonaticus sp. nov., type strain CDC 1058-77T (= LMG 23826T = DSMZ 18702T); C. turicensis sp. nov., type strain z3032T (= LMG 23827T = DSMZ 18703T); C. muytjensii sp. nov., type strain ATCC 51329T (= CIP 103581T); C. dublinensis sp. nov., type strain DES187T (= LMG 23823T = DSMZ 18705T); C. dublinensis sp. nov. subsp. dublinensis subsp. nov., type strain DES187T; C. dublinensis sp. nov. subsp. lausannensis subsp. nov., type strain E515T (= LMG 23824 = DSMZ 18706T); and C. dublinensis sp. nov. subsp. lactaridi subsp. nov. type strain E464T (= LMG 23825T = DSMZ 18707T).