Genome sequence of Cronobacter sakazakii BAA-894 and comparative genomic hybridization analysis with other Cronobacter species.
BACKGROUND
The genus Cronobacter (formerly called Enterobacter sakazakii) is composed of five species; C. sakazakii, C. malonaticus, C. turicensis, C. muytjensii, and C. dublinensis. The genus includes opportunistic human pathogens, and the first three species have been associated with neonatal infections. The most severe diseases are caused in neonates and include fatal necrotizing enterocolitis and meningitis. The genetic basis of the diversity within the genus is unknown, and few virulence traits have been identified.


RESULTS
We report here the first sequence of a member of this genus, C. sakazakii strain BAA-894. The genome of Cronobacter sakazakii strain BAA-894 comprises a 4.4 Mb chromosome (57% GC content) and two plasmids; 31 kb (51% GC) and 131 kb (56% GC). The genome was used to construct a 387,000 probe oligonucleotide tiling DNA microarray covering the whole genome. Comparative genomic hybridization (CGH) was undertaken on five other C. sakazakii strains, and representatives of the four other Cronobacter species. Among 4,382 annotated genes inspected in this study, about 55% of genes were common to all C. sakazakii strains and 43% were common to all Cronobacter strains, with 10-17% absence of genes.


CONCLUSIONS
CGH highlighted 15 clusters of genes in C. sakazakii BAA-894 that were divergent or absent in more than half of the tested strains; six of these are of probable prophage origin. Putative virulence factors were identified in these prophage and in other variable regions. A number of genes unique to Cronobacter species associated with neonatal infections (C. sakazakii, C. malonaticus and C. turicensis) were identified. These included a copper and silver resistance system known to be linked to invasion of the blood-brain barrier by neonatal meningitic strains of Escherichia coli. In addition, genes encoding for multidrug efflux pumps and adhesins were identified that were unique to C. sakazakii strains from outbreaks in neonatal intensive care units.
Kucerova
Eva
E
School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom.
Clifton
Sandra W
SW
Xia
Xiao-Qin
XQ
Long
Fred
F
Porwollik
Steffen
S
Fulton
Lucinda
L
Fronick
Catrina
C
Minx
Patrick
P
Kyung
Kim
K
Warren
Wesley
W
Fulton
Robert
R
Feng
Dongyan
D
Wollam
Aye
A
Shah
Neha
N
Bhonagiri
Veena
V
Nash
William E
WE
Hallsworth-Pepin
Kymberlie
K
Wilson
Richard K
RK
McClelland
Michael
M
Forsythe
Stephen J
SJ
D000818:Animals; D001435:Bacteriophages / Q000235:genetics; D016466:CHO Cells; D016000:Cluster Analysis; D055028:Comparative Genomic Hybridization; D006224:Cricetinae; D003412:Cricetulus; D004755:Enterobacteriaceae / Q000235:genetics*; D004756:Enterobacteriaceae Infections / Q000235:genetics / Q000382:microbiology*; D016678:Genome; D016680:Genome, Bacterial; D006801:Humans; D007231:Infant, Newborn; D008581:Meningitis / Q000382:microbiology; D013045:Species Specificity