...
Background:
...
Salmonella
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enterica
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subsp.
...
enterica
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serovar
...
Typhimurium
...
(antigenic
...
formula
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4,5,12:i:1,2)
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is
...
a
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widely
...
distributed
...
serovar,
...
representing
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the
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second
...
most
...
common
...
serovar
...
in
...
the
...
United
...
States
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and
...
the
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European
...
Union.
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This
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serovar
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belongs
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to
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the
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serogroup
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O:4
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(B),
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there
...
is
...
one
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variant
...
named
...
S.
...
Typhimurium
...
var.
...
Copenhagen,
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which
...
lacks
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the
...
factor
...
5
...
in
...
the
...
O
...
antigen
...
(4,12:i:1,2).
...
This
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serovar
...
was
...
named
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Typhimurium
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because
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it
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produces
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"Typhi
...
like
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symptoms
...
in
...
the
...
murine
...
model.
...
S.
...
Typhimurium
...
has
...
been
...
used
...
as
...
model
...
to
...
understand
...
the
...
pathogenicity
...
of
...
Salmonella.
...
Serovar Typhimurium can cause disease in a wide range of hosts and invasive strains have been reported in some African countries. This serovar is classified according to the susceptibility to typing phages (phage typing (PT));
...
one
...
common
...
PT
...
(PT104)
...
was
...
typically
...
found
...
to
...
have
...
resistance
...
to
...
ampicillin,
...
chloramphenicol,
...
streptomycin,
...
sulphonamide
...
and
...
tetracycline
...
(ACSSuT
...
resistance
...
type).
...
In
...
England
...
two
...
outbreaks
...
caused
...
by
...
a
...
multidrug-resistant
...
(ASSuTTm)
...
strain
...
of
...
S.
...
Typhimurium
...
DT120
...
occurred
...
in
...
2011.
...
Animal reservoir:
...
serovar
...
Typhimurium
...
is
...
found
...
in
...
multiple
...
animal
...
species,
...
including
...
cattle,
...
chickens,
...
turkey,
...
swine,
...
wild
...
animals
...
and
...
insects.
...
Geographical distribution: serovar Typhimurium is widely distributed. In the multiple locations (i.e.,
...
US,
...
the
...
EU,
...
Africa
...
and
...
Latin
...
America)
...
this
...
serovar
...
is
...
the
...
second
...
most
...
common
...
serovar.
...
In
...
Oceania
...
is
...
the
...
most
...
common
...
serovar.
...
In
...
Asia
...
is
...
among
...
the
...
ten
...
most
...
common
...
serovars.
...
Outbreaks:
...
numerous
...
of
...
outbreaks
...
have
...
been
...
associated
...
with
...
serovar
...
Typhimurium.
...
Outbreaks
...
have
...
been
...
linked
...
to
...
a
...
number
...
of
...
foods
...
and
...
also
...
been
...
linked
...
to
...
contact
...
with
...
live
...
poultry
...
(chicks,
...
ducklings,
...
and
...
other
...
live
...
baby
...
poultry).
...
Here
...
we
...
mention
...
the
...
latest
...
outbreaks
...
caused
...
by
...
this
...
serovar.
...
Year | Location | Associated source | Number of cases |
2013 | US-multistate | Live poultry | 37 |
2013 | US-multistate | Ground beef | 22 |
2012 | Canada | Ground beef | 50 |
2012 | US-multistate | Pet Hedgehogs | 26 |
2012 | US-multistate | Cantaloupe | 261 |
2011 | US-multistate | Ground beef | 20 |
2011 | US-multistate | African Dwarf Frogs | 241 |
2011 | England | Pork | 51 |
2011 | Ireland | Duck eggs | 34 |
2010 | US-multistate | Contact with water frogs | 85 |
2009 | England | unknown | 14 |
Relevant genetic characteristics: Whole genome sequences for 27 strains of S. Typhimurium have been deposited at GenBank as for October, 2013. Genomic characteristics of the sequenced S. Typhimurium include i) a genome size ranging from 4.82- 5.09 Mb, ii) a mol G+C% of approx. 52.2, and iii) 4,556-5,619
...
genes.
...
Typically,
...
strains
...
of
...
S.
...
Typhimurium
...
contain
...
a
...
plasmid
...
of
...
approx.
...
90
...
kb
...
that
...
carry
...
virulence
...
genes
...
(
...
Salmonella
...
virulence
...
plasmid
...
spv
...
operon).
...
Large
...
resistant
...
plasmids
...
of
...
approx.
...
200
...
kb,
...
representing
...
different
...
incompatibility
...
types
...
(e.g.,
...
IncHI1)
...
have
...
also
...
been
...
identified
...
in
...
the
...
sequenced
...
strains.
...
Prophages
...
and
...
genomic
...
islands
...
are
...
important
...
genomic
...
components
...
of
...
serovar
...
Typhimurium;
...
for
...
example,
...
S.
...
Typhimurium
...
str.
...
LT2
...
has
...
four
...
prophages
...
(Fels-1,
...
Fels-2,
...
Gifsy-1,
...
and
...
Gifsy-2);
...
within
...
S.
...
Typhimurium
...
strains,
...
the
...
prophage
...
content
...
shows
...
variation.
...
Pathogenicity
...
islands
...
(SPIs)
...
are
...
found
...
in
...
all
...
S.
...
Typhimurium
...
sequenced
...
to
...
date,
...
including
...
SPIs-1
...
to
...
6,
...
9,
...
11
...
to
...
14,
...
and
...
16;
...
being
...
SPI14
...
specific
...
to
...
Typhimurium.
...
In
...
addition,
...
genomic
...
island
...
content
...
shows
...
variation;
...
for
...
example,
...
S.
...
Typhimurium
...
MDR
...
strain
...
ST1660/06
...
has
...
three
...
strain-specific
...
genomic
...
islands
...
encoding
...
putative
...
virulence
...
and
...
resistance
...
genes.
...
Genomic
...
islands
...
carrying
...
antibiotic
...
resistance
...
appear
...
to
...
be
...
a
...
common
...
feature
...
of
...
a
...
number
...
of
...
S.
...
Typhimurium
...
MDR
...
strains,
...
these
...
genomic
...
islands
...
include,
...
e.g.,
...
Salmonella
...
genomic
...
island
...
1
...
(SGI1)
...
described
...
in
...
S.
...
Typhimurium
...
DT104
...
and
...
GI-DT12
...
in
...
S.
...
Typhimurium
...
T000240.
...
The
...
latest
...
genomic
...
island
...
(GI-DT12)
...
contains
...
resistance
...
genes
...
(i.e.,
...
bla(oxa-30),
...
aadA1,
...
qacEΔ1,
...
and
...
sul1
...
,
...
mercury
...
resistance
...
proteins,
...
cat,
...
and
...
tetA
...
)
...
and
...
virulence
...
genes
...
(i.e.,
...
the
...
aerobactin
...
iron-acquisition
...
siderophore
...
system
...
(
...
lutA
...
and
...
lucABC
...
),
...
and
...
an
...
iron
...
transporter
...
(
...
sitABCD
...
)).
...
In
...
Sub-Sahara
...
regions
...
of
...
Africa
...
invasive
...
strains
...
of
...
S.
...
Typhimurium
...
emerged,
...
single
...
nucleotide
...
polymorphism
...
(SNP)-based
...
phylogeny
...
of
...
this
...
invasive
...
strains
...
and
...
strains
...
from
...
other
...
regions
...
showed
...
two
...
lineages
...
that
...
clustered
...
together.
...
According
...
to
...
den
...
Bakker
...
et
...
al.
...
(2011)
...
classification,
...
Salmonella
...
Typhimurium
...
belongs
...
to
...
clade
...
A.
...
Genome sequences available:
- Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 http://www.ncbi.nlm.nih.gov/assembly/28528/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. 14028S http://www.ncbi.nlm.nih.gov/assembly/359508/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. 798 http://www.ncbi.nlm.nih.gov/assembly/368468/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. D23580 http://www.ncbi.nlm.nih.gov/assembly/359488/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. SL1344 http://www.ncbi.nlm.nih.gov/assembly/445688/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. ST4/74 http://www.ncbi.nlm.nih.gov/assembly/378298/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. T000240 http://www.ncbi.nlm.nih.gov/assembly/407038/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. U288 http://www.ncbi.nlm.nih.gov/assembly/608548/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. UK1 http://www.ncbi.nlm.nih.gov/assembly/360258/
...
- Salmonella enterica subsp. enterica serovar Typhimurium var-5
...
- str.
...
- CFSAN001921
...
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. ST1489 http://www.ncbi.nlm.nih.gov/assembly/62931/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. ST1660/06 http://www.ncbi.nlm.nih.gov/assembly/546838/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. ST4848 http://www.ncbi.nlm.nih.gov/assembly/64311/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. ST78896 http://www.ncbi.nlm.nih.gov/assembly/62921/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm1 http://www.ncbi.nlm.nih.gov/assembly/493428/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm10 http://www.ncbi.nlm.nih.gov/assembly/503588/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm11 http://www.ncbi.nlm.nih.gov/assembly/503608/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm12 http://www.ncbi.nlm.nih.gov/assembly/503628/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm2 http://www.ncbi.nlm.nih.gov/assembly/499908/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm3 http://www.ncbi.nlm.nih.gov/assembly/503528/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm4 http://www.ncbi.nlm.nih.gov/assembly/503548/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm5 http://www.ncbi.nlm.nih.gov/assembly/503648/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm6 http://www.ncbi.nlm.nih.gov/assembly/503568/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm7 http://www.ncbi.nlm.nih.gov/assembly/47901/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm8 http://www.ncbi.nlm.nih.gov/assembly/503508/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. STm9 http://www.ncbi.nlm.nih.gov/assembly/506978/
...
- Salmonella enterica subsp. enterica serovar Typhimurium str. TN061786 http://www.ncbi.nlm.nih.gov/assembly/356608/
...
Relevant links:
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