Increased Prevalence and
diversity of VTEC in
Ireland: Fact of Artifact?
Dr Anne Carroll
Dr Eleanor McNamara
HSE-PHL-Dublin
PHL Scope
 Official testing laboratory, Food and water
(S.I. 85 of 1998 and S.I. 117 of 2010) .
 Accredited ISO 17025
 National VTEC diagnostic and typing service
(Clinical, foods water environmental)
 Clinical diagnostic general microbiology
service, hospital/GP
HSE-PHL-Dublin
VTEC Reference Service
 National VTEC Service





Stools, Food, Water.
Isolate Confirmation
Accredited
PCR >22,000 tests
PFGE
HSE-PHL-Dublin
VTEC incidence
Year
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Numbers of Incidence/100000
VTEC
cases
1.7
68
2.1
82
1.4
51
3.0
123
3.7
159
3.9
115
5.3
223
5.7
240
4.8
202
5.9
270
7
6
5
4
Total
O157
non-O
3
2
1
0
Year 2002
Year 2003
Year 2004
Year 2005
Year 2006
Year 2007
Incidence/100000
HSE-PHL-Dublin
Year 2008
Year 2009
Year 2010
Year 2011
VTEC incidence
Year
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Year
2004
2005
2006
2007
2008
2009
2010
2011
Numbers of Incidence/100000
VTEC
cases
1.7
68
2.1
82
1.4
51
3.0
123
3.7
159
3.9
115
5.3
223
5.7
240
4.8
202
5.9
270
7
6
5
4
Total
O157
non-O
3
2
No. Samples % positive
1
Analysed*
cases
599
8.5
0
996
12.3
1360
11.7
1468
10.8
2403
9.3
3550
6.8
3283
6.2
4943
5.5
Year 2002
Year 2003
Year 2004
Year 2005
Year 2006
Year 2007
Incidence/100000
HSE-PHL-Dublin
Year 2008
Year 2009
Year 2010
Year 2011
VTEC Serogroups
100%
90%
80%
70%
60%
Other
O26
O157
50%
40%
30%
20%
10%
0%
year 2004
year 2005
year 2006
year 2007
year 2008
year 2009
HSE-PHL-Dublin
Year 2010
Year 2011
2011 VTEC serogroups
Serogroup
O157
O26
O111
O128ad
O145
O146
O150
O185
O5
O76
O44
O91
O130
O149
O166
O6
O8
Ungroupable
vtx1(%)
0(0)
29(58)
vtx2(%)
153(72.5)
1(2)
0
0
0 3(100)
0
0
0 1(100)
6(75)
1(100)
0
0 3(100)
0 2(100)
0
0 2(25)
0
0 1(100)
0
0 1(100)
1(100)
0
4(100)
0
3(25)
vtx1+vtx2(%)
58(27.5)
20(40)
0 1(100)
0 1(100)
4(33.4)
0
0
0 1(100)
0
0 1(100)
0
1
5(41.6)
0
0
0
0
Total No.(%)
211 (100)
50 (100)
1 (100)
1 (100)
3 (100)
3 (100)
2 (100)
1 (100)
8 (100)
1 (100)
1 (100)
1 (100)
1 (100)
1 (100)
1 (100)
4 (100)
1 (100)
12 (100)
HSE-PHL-Dublin
2011: 17
serogroups
15 clinical +2
food
2002-2011 33
serogroups +
 2011 HPSC VTEC subgroup





HPSC
Ref lab
5 labs
Public health
Consensus + recommend standardised
methods for VTEC
HSE-PHL-Dublin
Risk
Risk
USA
ROI
Scotland
E&W
Nordic
Bloody diarrhoea




HUS




Isolates




OB contacts

symptomatic


(O157) ?
(O157)
(O157)
(optimal)
Community acq Diarrhoea

Food handler

Abdominal Cramps

Contact with ruminants

Consumption raw animal
products or raw fruits/veg

Contact with animal products
e.g. manure

Hospitalised

HSE-PHL-Dublin
Lab Methods US
“all stools submitted for routine testing from
patients be simultaneously cultured for
O157 and tested with an assay that detects
Shiga toxins to detect non-O157 STEC”
“Specimens or enrichment broths in which
Shiga toxin or STEC are detected but from
which O157 STEC are not recovered
should be forwarded as soon as possible
to a state or local public health laboratory”.
HSE-PHL-Dublin
Lab Methods ROI
Method
Risk
1
2
3
4
5
6
CT-SMAC
/Chrom
High










Agglutination
O157
High










Enrichment
High
Low
Low
(outbreakO157)


(outbreakO157)
(O157, O26, O111)
Low
IMS
High
Low
Non-O157
agglutination
High
O157 gene
detection
High
VT gene
detection
High



Low
Low








Low
HSE-PHL-Dublin
 Lab 1
Method
Risk
1
CT-SMAC
/Chrom
High


Agglutination
O157
High
Enrichment
High
Low
Low


Low
IMS
High
Low
Non-O157
agglutination
High
O157 gene
detection
High
VT gene
detection
High

Low
Low


Low
HSE-PHL-Dublin
 Lab 1
Method
Risk
1
CT-SMAC
/Chrom
High


Agglutination
O157
High
Enrichment
High
Low
Low


Low
IMS
High
Low
Non-O157
agglutination
High
O157 gene
detection
High
VT gene
detection
High

Low
Low
Low




HSE-PHL-Dublin
2012
Jan-Apr
2012
2011
2010
2009
14
0
0
1
(3xO103,
1xO111, 5x
ungp, 1x O145,
4xO26)
Whole
year
(1x O105 ac)
4
4
12
(1x ungp, 1x
O150, 1x O91,
1x O26) All
picked up by ref
lab as part of
O157 OB screen
(1xO121, 3x
O26)
(1x O105 ac, 4x
ungp, 1x O145,
1x O103, 1x
O178, 4x O26) 7
picked up by ref
lab as part of OB
screen
Pre 2012 samples referred to ref lab based on risk and not lab findings (stools).
HSE-PHL-Dublin
 Lab 7
Method
Risk
7
CT-SMAC
/Chrom
High


Agglutination
O157
High
Enrichment
High
Low
Low


Low
IMS
High
Low
Non-O157
agglutination
High
O157 gene
detection
High
VT gene
detection
High

Low
Low
Low
HSE-PHL-Dublin
 Lab 7
Method
Risk
7
CT-SMAC
/Chrom
High


Agglutination
O157
High
Enrichment
High
Low
Low


STEC
CHROMagar
Low
IMS
High
Low
Non-O157
agglutination
High
O157 gene
detection
High
VT gene
detection
High

Low
Low
Low
HSE-PHL-Dublin
Jan-Apr
Whole
year
2012
2011
2010
2009
10
1
0
2
(2x O145, 7x
O26, 1x ungp)
(1xO26)
(2xO26)
4
3
3
(3x O26, 1x O5)
O5 picked up by
ref lab as part of
OB screen
(1xungp, 2xO26)
(3xO26)
Pre 2012 samples referred to ref lab primarily based on lab findings and not risk (Isolates)
HSE-PHL-Dublin
Lab 2
Method
Risk
2
CT-SMAC
/Chrom
High


Low
Agglutination
O157
High


Low
Enrichment
High
No changes to
methods
Low
IMS
High
Low
Non-O157
agglutination
High

Low
O157 gene
detection
High
Low
VT gene
detection
High
Low
HSE-PHL-Dublin
Jan-Apr
Whole
year
2012
2011
2010
2009
14
12
2
4
(14x O26)
(9xO26, 3xO146)
(2xO26)
(4xO26)
41
27
12
(28x O26, 1x
O150, 1xO44,
2xO5, 1xO76,
3xO146, 5x
ungp)
(27xO26)
(5xO26, 3xungp,
2x O121, 2x
O132)
samples referred to ref lab based on both lab findings and risk (stools and isolates)
HSE-PHL-Dublin
Issues
 PCR Direct from stool
 PCR pos culture negative issue
 Direct detection of vt1 or vt2 gene(s) (without
strain isolation), probable or confirmed
depending on clinical criteria (HPSC)
HSE-PHL-Dublin
Issues
 Ref lab
 Direct PCR, Enrichment/IMS PCR, colony
confirmation.
1.
2.
3.

Direct PCR pos and/or Enrichment/IMS PCR
pos + colony confirmed
Direct PCR pos + Enrichment/IMS PCR pos
but can’t isolate colony
Direct PCR pos + Enrichment/IMS PCR neg
Do 2 +3 have the same PH implications?
HSE-PHL-Dublin
2)



Direct PCR pos + Enrichment/IMS PCR pos
but can’t isolate colony
Organism seems to be growing viable
Shedding of viable organism possible PH
risk
Source of infection
HSE-PHL-Dublin
3) Direct PCR pos + Enrichment/IMS PCR neg




Organism not growing
not viable
Shedding of non viable organism not a PH
risk
May have been infection with organism
subsequently dying source of infection
May have been no infection but ingestion of
non viable organism e.g. from treated water
or processed food
HSE-PHL-Dublin
 If Use PCR only result (2 or 3) may not be
true result

O26 vt2 PCR pos



O26 vt2
O26 vt neg + other serogroup vt2 pos
O26 vt2 + other serogroup vt2 pos
HSE-PHL-Dublin
Challenges
 Methods
 Risk
 Transport
 Facilities
 IT
HSE-PHL-Dublin
Summary
  VTEC in recent years
 Particularly in non-O157 VTEC
 Introduction of mandatory notification
 Increased awareness non-O157 VTEC
 Recent increases of non-O157 VTEC can be
attributed to more targeted methods
 Challenges
 Clinical and lab findings need to be taken
together
 Lab + PH need to communicate
HSE-PHL-Dublin
Thank You
Thank you to dedicated
PHL Staff
HSE-PHL-Dublin
VTEC Reference Service
Outbreak Service
 Primary High Risk sample analysis
 Confirmation and Typing
 Medical advisory service
 OCT
 Data collation
HSE-PHL-Dublin