Use of a Pan-Genomic DNA Microarray in Determination of the Phylogenetic Relatedness among Cronobacter spp. and Its Use as a Data Mining Tool to Understand Cronobacter Biology.

(previously known as ) is a genus of Gram-negative, facultatively anaerobic, oxidase-negative, catalase-positive, rod-shaped bacteria of the family . These organisms cause a variety of illnesses such as meningitis, necrotizing enterocolitis, and septicemia in neonates and infants, and urinary tract, wound, abscesses or surgical site infections, septicemia, and pneumonia in adults. The total gene content of 379 strains of spp.

Analysis and Characterization of Proteins Associated with Outer Membrane Vesicles Secreted by spp.

Little is known about secretion of outer membrane vesicles (OMVs) by . In this study, OMVs isolated from , and were examined by electron microscopy (EM) and their associated outer membrane proteins (OMP) and genes were analyzed by SDS-PAGE, protein sequencing, BLAST, PCR, and DNA microarray. EM of stained cells revealed that the OMVs are secreted as pleomorphic micro-vesicles which cascade from the cell's surface.

Genome Sequences of Malonate-Positive Cronobacter sakazakii Serogroup O:2, Sequence Type 64 Strains CDC 1121-73 and GK1025, Isolated from Human Bronchial Wash and a Powdered Infant Formula Manufacturing Plant.

We introduce draft genome sequences of strains CDC1121-73 (human bronchial wash isolate) and GK1025 (powdered infant formula manufacturing facility isolate), which are both malonate-positive Cronobacter sakazakii serogroup O:2, sequence type 64. Assemblies for these strains have sizes of 4,442,307 and 4,599,266 bp and % G+C contents of 56.9 and 56.

Analysis of the cellulose synthase operon genes, bcsA, bcsB, and bcsC in Cronobacter species: Prevalence among species and their roles in biofilm formation and cell-cell aggregation.

Cronobacter species are emerging food-borne pathogens that cause severe sepsis, meningitis, and necrotizing entercolitis in neonates and infants. Bacterial pathogens such as Escherichia coli and Salmonella species produce extracellular cellulose which has been shown to be involved in rugosity, biofilm formation, and host colonization. In this study the distribution and prevalence of cellulose synthase operon genes (bcsABZC) were determined by polymerase chain reaction (PCR) analysis in 231 Cronobacter strains isolated from clinical, food, environmental, and unknown sources.

Genome Sequence of Cronobacter sakazakii Serogroup O:4, Sequence Type 4 Strain CDC 2009-03746, Isolated from a Fatal Case of Infantile Meningitis.

We report the draft genome sequence of a Cronobacter sakazakii serogroup O:4, sequence type 4 strain, CDC 2009-03746 (=NM1240=2009-06-01), isolated from a fatal case of infantile meningitis. The draft genome has a size of 4,492,904 bp and a G+C% content of 56.7.

A proposed harmonized LPS molecular-subtyping scheme for Cronobacter species.

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.

Development of a Custom-Designed, Pan Genomic DNA Microarray to Characterize Strain-Level Diversity among Cronobacter spp.

Cronobacter species cause infections in all age groups; however neonates are at highest risk and remain the most susceptible age group for life-threatening invasive disease. The genus contains seven species:Cronobacter sakazakii, Cronobacter malonaticus, Cronobacter turicensis, Cronobacter muytjensii, Cronobacter dublinensis, Cronobacter universalis, and Cronobacter condimenti. Despite an abundance of published genomes of these species, genomics-based epidemiology of the genus is not well established.

Re-examination of the taxonomic status of Enterobacter helveticus, Enterobacter pulveris and Enterobacter turicensis as members of the genus Cronobacter and their reclassification in the genera Franconibacter gen. nov. and Siccibacter gen. nov. as Franconibacter helveticus comb. nov., Franconibacter pulveris comb. nov. and Siccibacter turicensis comb. nov., respectively.

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.

Genome Sequence of an Enterobacter helveticus Strain, 1159/04 (LMG 23733), Isolated from Fruit Powder.

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.

Genome Sequences of Two Enterobacter pulveris Strains, 601/05T (=LMG 24057T =DSM 19144T) and 1160/04 (=LMG 24058 =DSM 19146), Isolated from Fruit Powder.

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.

Pan-genome analysis of the emerging foodborne pathogen Cronobacter spp. suggests a species-level bidirectional divergence driven by niche adaptation.

Background: Members of the genus Cronobacter are causes of rare but severe illness in neonates and preterm infants following the ingestion of contaminated infant formula. Seven species have been described and two of the species genomes were subsequently published. In this study, we performed comparative genomics on eight strains of Cronobacter, including six that we sequenced (representing six of the seven species) and two previously published, closed genomes.

Identification and characterization of five new molecular serogroups of Cronobacter spp.

Cronobacter spp. (formerly Enterobacter sakazakii) is an emerging foodborne pathogen consisting of seven species including C. sakazakii, C.

The Pathogen-annotated Tracking Resource Network (PATRN) system: a web-based resource to aid food safety, regulatory science, and investigations of foodborne pathogens and disease.

Investigation of foodborne diseases requires the capture and analysis of time-sensitive information on microbial pathogens that is derived from multiple analytical methods and sources. The web-based Pathogen-annotated Tracking Resource Network (PATRN) system (www.patrn.

Cronobacter spp. (previously Enterobacter sakazakii) invade and translocate across both cultured human intestinal epithelial cells and human brain microvascular endothelial cells.

The mechanism of Cronobacter pathogenesis in neonatal meningitis and potential virulence factors (aside from host cell invasion ability) remain largely unknown. To ascertain whether Cronobacter can invade and transcytose across intestinal epithelial cells, enter into the blood stream and then transcytose across the blood-brain-barrier, we have utilized human intestinal INT407 and Caco-2 cells and brain microvascular endothelial cell (HBMEC) monolayers on Transwell filters as experimental model systems. Our data indicate a wide range of heterogeneity with respect to invasion efficiency among twenty-three Cronobacter isolates screened.

Cloning and partial characterization of a novel hemolysin gene of Vibrio tubiashii and the development of a PCR-based detection assay.

Vibrio tubiashii expresses virulence factors, such as a vulnificolysin-like hemolysin or cytolysin and a zinc metalloprotease, similar to those of other pathogenic vibrios. In this study, we report the cloning of a novel hemolysin gene of V. tubiashii in Escherichia coli .

Molecular characterization of Cronobacter lipopolysaccharide O-antigen gene clusters and development of serotype-specific PCR assays.

Cronobacter (formerly Enterobacter sakazakii) is a recently defined genus consisting of six species, C. sakazakii, C. malonaticus, C.

Characterization of putative virulence genes on the related RepFIB plasmids harbored by Cronobacter spp.

Cronobacter spp. are emerging neonatal pathogens that cause meningitis, sepsis, and necrotizing enterocolitis. The genus Chronobacter consists of six species: C.

Cloning, expression and characterization of the CHO cell elongating factor (Cef) from Vibrio cholerae O1.

CHO cell-elongating factor (Cef) is a recently identified putative virulence factor of Vibrio cholerae. Our previous studies show that this 85 kDa protein elongates CHO cells, causes fluid accumulation in suckling mice and has esterase activity. In this study, the cef gene was cloned in Escherichia coli using a yeast vector and subsequently expressed in the yeast Pichia pastoris.

Purification and characterization of a cytotonic protein expressed In vitro by the live cholera vaccine candidate CVD 103-HgR.

Cholera vaccines developed by the deletion of CTX genes from Vibrio cholerae induce a residual reactogenicity in up to 10% of vaccinees. A novel cytotonic agent named secreted CHO cell elongating protein (S-CEP) was purified from culture supernatants of CVD 103-HgR (Levine et al., Lancet ii:467-470, 1988).

Glutamate Release from Chick Retina Explants in Response to Domoic Acid.

Release of endogenous glutamate (GLU) evoked by an exogenous excitotoxin such as kainate can contribute to central nervous system (CNS) excitotoxicity. In this study, the possibility that this mechanism accounts for reported domoic acid (DOM) toxicity was investigated using the isolated chick retina. Exposing retinas to 0-100 µM DOM for 40 min caused an increased efflux of lactate dehydrogenase (LDH) and a dose-related release of GLU into the incubation medium.

Identification of a CHO cell-elongating factor produced by Vibrio cholerae O1.

Vibrio cholerae strains with all known toxin genes deleted or inactivated still cause diarrhoea in some volunteers, suggesting the presence of an unknown virulence factor or factors. Lysozyme-EDTA treated cells of JBK70, a genetically manipulated cholera toxin negative strain of Vibrio cholerae O1, biotype El Tor, release a factor that causes elongation of Chinese hamster ovary (CHO) cells. CHO cell-elongating toxin (Cef) was purified by FPLC chromatography (anion exchange; Q Sepharose High Performance) followed by 2D electrophoresis (isoelectric focusing gel, IEF; pH 3-9 and SDS-PAGE, 8-25% gradient gel).

Characterization of a 20-kDa pilus protein expressed by a diarrheogenic strain of non-O1/non-O139 Vibrio cholerae.

A diarrheogenic strain of non-O1/non-O139 Vibrio cholerae (10,325) belonging to serogroup O34 was earlier shown to express a new type of pilus composed of a 20-kDa subunit protein. Amino-terminal sequence data (determined up to 20 amino acid residues) of this protein showed it to be different from the subunit proteins of other known types of pili of V. cholerae.