ABSTRACT
Cronobacter are opportunistic pathogens, which cause infections in all age groups. To aid the characterization of Cronobacter in foods and environments a harmonized LPS identification scheme for molecular serotyping is needed. To this end, we studied 409 Cronobacter isolates representing the seven Cronobacter species using two previously reported molecular serotyping schemes, described here as Mullane-Jarvis (M-J) and Sun schemes. PCR analysis revealed many overlapping results that were obtained when independently applying the two serotyping schemes. There were complete agreements between the two PCR schemes for Cronobacter sakazakii (Csak) O:1, Csak O:3, and Csak O:7 serotypes. However, only thirty-five of 41 Csak O:4 strains, identified using the M-J scheme, were PCR-positive with the Sun scheme primers. Also the Sun scheme Csak O:5 primers failed to identify this serotype in any of the C. sakazakii strains tested, but did recognize seven Cronobacter turicensis strains, which were identified as Ctur O:3 using the M-J scheme. Similarly, the Sun scheme Csak O:6 primers recognized 30 Cronobacter malonaticus O:2 strains identified with the M-J scheme, but failed to identify this serotype in any C. sakazakii strain investigated. In this report, these findings are summarized and a harmonized molecular-serotyping scheme is proposed which is predicated on the correct identification of Cronobacter species, prior to serotype determination. In summary, fourteen serotypes were identified using the combined protocol, which consists of Csak O:1-O:4, and Csak O:7; Cmal O:1-O:2; Cdub O:1-O:2, Cmuy O:1-O:2, Cuni O:1, as well as Ctur O:1 and Ctur O:3.
Subject(s)
Cronobacter/classification , Lipopolysaccharides/genetics , Molecular Typing/methods , Serotyping/methods , Cronobacter/genetics , Cronobacter/growth & development , Cronobacter/isolation & purification , Cronobacter sakazakii/classification , Cronobacter sakazakii/genetics , Cronobacter sakazakii/isolation & purification , DNA Primers , Electrophoresis, Polyacrylamide Gel , Food Microbiology , Lipopolysaccharides/chemistry , Lipopolysaccharides/isolation & purification , Polymerase Chain Reaction , Species SpecificityABSTRACT
Recently, a taxonomical re-evaluation of the genus Enterobacter, based on multi-locus sequence typing (MLST) analysis, has led to the proposal that the species Enterobacter pulveris, Enterobacter helveticus and Enterobacter turicensis should be reclassified as novel species of the genus Cronobacter. In the present work, new genome-scale analyses, including average nucleotide identity, genome-scale phylogeny and k-mer analysis, coupled with previously reported DNA-DNA hybridization values and biochemical characterization strongly indicate that these three species of the genus Enterobacter are not members of the genus Cronobacter, nor do they belong to the re-evaluated genus Enterobacter. Furthermore, data from this polyphasic study indicated that all three species constitute two new genera. We propose reclassifying Enterobacter pulveris and Enterobacter helveticus in the genus Franconibacter gen. nov. as Franconibacter pulveris comb. nov. (type strain 601/05(T) = LMG 24057(T) = DSM 19144(T)) and Franconibacter helveticus comb. nov. (type strain 513/05(T) = LMG 23732(T) = DSM 18396(T)), respectively, and Enterobacter turicensis in the genus Siccibacter gen. nov. as Siccibacter turicensis comb. nov. (type strain 508/05(T) = LMG 23730(T) = DSM 18397(T)).
Subject(s)
Cronobacter/classification , Enterobacter/classification , Enterobacteriaceae/classification , Phylogeny , Bacterial Typing Techniques , Cronobacter/genetics , DNA, Bacterial/genetics , Enterobacter/genetics , Enterobacteriaceae/genetics , Genes, Bacterial , Molecular Sequence Data , Multilocus Sequence Typing , Nucleic Acid Hybridization , Polymorphism, Single Nucleotide , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNAABSTRACT
We report the draft genome sequences of the Enterobacter pulveris strains 601/05(T) (=LMG24057(T) =DSM19144(T)) and 1160/04 (=LMG24058 =DSM19146), isolated from fruit powder. The genome assemblies for the E. pulveris type strain, LMG24057, and strain LMG24058 have sizes of 4,708,624 and 4,811,103 bp and G+C contents of 56.6% and 56.5%, respectively.
ABSTRACT
We report the draft genome sequence of Enterobacter turicensis strain 610/05 (LMG 23731), isolated from fruit powder. The draft genome has a size of 4,182,790 bp and a G+C% content of 58.0.
ABSTRACT
We report the draft genome sequence of Enterobacter helveticus strain LMG 23733, isolated from fruit powder. The draft genome assembly for E. helveticus strain LMG 23733 has a size of 4,635,476 bp and a G+C content of 55.9%.