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TRANSCRIPT
Impact of Abiotic and Biotic Parameters of the Human Gut on
Enterohemorrhagic Escherichia coli Survival and Virulence
IAFP's 13th European Symposium on Food Safety 29th March 2017, Brussels, Belgium
Stéphanie Blanquet-DiotAssociate professor, University of Clermont Auvergne, France
Université Clermont Auvergne, Clermont-Ferrand, FranceUMR UCA-INRA 454 MEDIS « Microbiota, Digestive Environment and Health »
Pr. Pierre Peyret
Introduction Conclusion
Clermont-Ferrand
Abiotic factors Biotic factors
Intestinal microbiota :main functions and impact on human and animal health
Galenicformulation
ARTIFICIAL DIGESTION /
FERMENTATION
Gnotobiotic animalsAnalytic infrastructure
Aerobic/anaerobic microbiologyBioinformatics
Molecular tools
Université Clermont Auvergne, Clermont-Ferrand, FranceUMR UCA-INRA 454 MEDIS « Microbiota, Digestive Environment and Health »
Pr. Pierre Peyret
Introduction ConclusionAbiotic factors Biotic factors
Intestinal microbiota :main functions and impact on human and animal health
Université Clermont Auvergne, Clermont-Ferrand, FranceUMR UCA-INRA 454 MEDIS « Microbiota, Digestive Environment and Health »
Pr. Pierre Peyret
Introduction ConclusionAbiotic factors Biotic factors
3 main research axes
► Food and xenobiotic metabolism
► Host-microbiota interactions
► Food-borne zoonotic diseases
ENTEROHEMORRHAGIC ESCHERICHIA COLI (EHEC)(O157:H7)
Major food-borne pathogens
→ Bloody diarrhea, hemorrhagic colitis
→ Life-threatening systemic complications
Real public health problem
Tarr et al., Lancet, 2005Pennington, Lancet, 2010
Karmali et al., Lancet, 1983
1982
Introduction ConclusionAbiotic factors Biotic factors
RESERVOIRS
TRANSMISSION VIA CONTAMINATEDFOOD AND WATER
PHYSIOPATHOLOGY
Introduction ConclusionAbiotic factors Biotic factors
RESERVOIRS
TRANSMISSION VIA CONTAMINATEDFOOD AND WATER
PHYSIOPATHOLOGY
ACID RESISTANCE
Introduction ConclusionAbiotic factors Biotic factors
BLOODY DIARRHEA
SHIGA TOXINS
RESERVOIRS
ATTACHMENT ANDEFFACEMENT LESIONS
INTIMIN
WATERY DIARRHEA
TRANSMISSION VIA CONTAMINATEDFOOD AND WATER
ACID RESISTANCE
PHYSIOPATHOLOGY
Introduction ConclusionAbiotic factors Biotic factors
BLOODY DIARRHEA
SHIGA TOXINS
BLOODSTREAM
RESERVOIRS
ATTACHMENT ANDEFFACEMENT LESIONS
INTIMIN
WATERY DIARRHEA
TRANSMISSION VIA CONTAMINATEDFOOD AND WATER
ACID RESISTANCE B Lymphocyte
T Lymphocyte
PEYER’S PATCHES
M cellMacrophage
MAPK
IL8
CROSS THE INTESTINAL BARRIER
Schüller, Toxins, 2011Etienne-Mesmin et al., PLoS One, 2011
PHYSIOPATHOLOGY
Introduction ConclusionAbiotic factors Biotic factors
BLOODY DIARRHEA
SHIGA TOXINS
BLOODSTREAM
RESERVOIRS
ATTACHMENT ANDEFFACEMENT LESIONS
INTIMIN
WATERY DIARRHEA
TRANSMISSION VIA CONTAMINATEDFOOD AND WATER
ACID RESISTANCE
PHYSIOPATHOLOGY
KIDNEY
HEMOLYTIC UREMIC SYNDROME (HUS)
TROMBOTIC TROMBOCYTOPENIC
PURPURA (PTT)
BRAIN
Introduction ConclusionAbiotic factors Biotic factors
EHEC
INTERACTIONS WITH HUMAN GUT MICROBIOTA?
HUMAN GI TRACT = A BLACK BOX…
SURVIVAL?
EXPRESSION OF VIRULENCE GENES?
Introduction ConclusionAbiotic factors Biotic factors
Mono-compartmentalstatic in vitro models
Nu
mb
ero
f s
tud
ies
Digestive complexity
Introduction ConclusionAbiotic factors Biotic factors
Multi-compartmentaldynamic in vitro models
Acid pH
Bile
SCFA
Isolated strains from gut microbiota
• Far from in vivo complexity• Only one digestive parameter
at the same timeHouse et al., Microbiol, 2009
Hammer et al., PLOS One, 2013
Connolly et al., Front. Microbiol., 2015
Pifer and Sperandio, Microbiol. Spectrum, 2014
OUTSTANDING QUESTION 1How EHEC survival and virulence are modulated
thoughout the human GI tract?
ANTIBIOTIC THERAPY IS CONTROVERSIAL↑ Toxin synthesis
↑ Risk of developing HUS
SYMPTOMATIC TREATMENT
Wong et al., N. Eng. J. Med., 2000CDC, 2011
TREATMENT OF EHEC INFECTIONS
Introduction ConclusionAbiotic factors Biotic factors
NO MARKETED VACCINEGarcia-Angulo et al., Vaccine, 2013
ALTERNATIVE STRATEGIES
Introduction ConclusionAbiotic factors Biotic factors
PROBIOTICS
“Live microorganisms which, when administered in adequate amounts, confer a health benefit on the host”
FAO/WHO, 2002Hill et al., Nat Rev Gastroenterol
Hepatol, 2014
In vitro In vivo
Acid pH, bile, SCFA…
ANTAGONISTIC POTENTIAL OF PROBIOTICSON EHEC PATHOGEN
Eaton et al., 2011Medellin-Pena et al., 2007
Carey et al., 2008
Dalmasso et al., 2006
Tsai et al., 2010
Gagnon et al., 2006
Arena et al., 2014
Fukuda et al., 2011
Kim et al., 2008
Introduction ConclusionAbiotic factors Biotic factors
BACTERIA
- Lactobacillus
- Bifidobacterium
YEAST
- Saccharomyces cerevisiae var boulardii
Cordonnier et al., Crit. Rev. Microbiol., 2015
Introduction ConclusionAbiotic factors Biotic factors
Effect of probiotic on human gut microbiota modulationin the context of EHEC infection ?
YEAST
- Saccharomyces cerevisiae var boulardii
- Saccharomyces cerevisiae CNCM I-3856
AIEC/miceSivignon et al., Infl. Bowel Dis., 2015
Pineton de Chambrun et al., Dig. Liver Dis., 2015 ; Cayzeele-Decherf et al., World J. Gastroenterol., 2017
Anti-inflammatoryproperties
Reduction of digestivediscomfort and abdominal pain in IBS patients
Improvement of Intestinal barrier function
AIEC/miceSivignon et al., Infl. Bowel Dis., 2015
ETEC/ intestinal epithelial cellsZanello et al., PLoS One, 2011
chemically-induced colitis/miceFoligné et al., World J. Gastroenterol., 2010
Introduction ConclusionAbiotic factors Biotic factors
OUTSTANDING QUESTION 2Can Saccharomyces cerevisiae CNCM I-3856 be useful
in the control of EHEC infections ?
PHYSICO-CHEMICALPARAMETERS
INTESTINALMICROBIOTA
ABIOTIC FACTORS BIOTIC FACTORS
Introduction ConclusionAbiotic factors Biotic factors
Impact of Abiotic and Biotic Parameters of the Human Gut
on EHEC Survival and Virulence
PHYSICO-CHEMICALPARAMETERS
INTESTINALMICROBIOTA
ABIOTIC FACTORS BIOTIC FACTORS
ConclusionBiotic factors
Impact of Abiotic and Biotic Parameters of the Human Gut
on EHEC Survival and Virulence
Introduction Abiotic factors
STOMACH
SMALL INTESTINE
Multi-compartmentaldynamic gastro-intestinal model
SIMULATED PARAMETERS
Body temperature
Temporal and longitunalchanges in gastric and
intestinal pH
Chyme mixing
Transit time
Gastric and ileal deliveries
Digestive secretions(pepsin, lipase,
pancreatic juice, bile)
Passive absorption(dialysis)Minekus et al., Atla, 1995
Guerra et al., Trends Biotechnol., 2012Cordonnier et al., Microorganisms, 2015
Stomach
Ileum
Jejunum
Duodenum
TIMTNO gastroIntestinal Model
ConclusionBiotic factorsIntroduction Abiotic factors
Experimental plan
Water
Roussel et al., Ped. Res., 2016
ConclusionBiotic factorsIntroduction Abiotic factors
CHILD ADULT
EHEC O157:H7 EDL 933 (107 CFU/mL)
Digestive compartmentsn = 4
NumerationLB medium
SURVIVAL
Water
VIRULENCE
Propidiumiodide
SYTO 9
Flow cytometryLife/dead analysis
Viable Altered
qRT-PCR (stx, shigatoxin)(eae, intimin)
ELISA (Stx)
TIM
ConclusionBiotic factorsIntroduction Abiotic factors
Experimental plan
Healthy childHealthy adult
Results : effect of « age » on EHEC survival 0157:H7Transit marker
Adult Child
EHEC survival unaffected in the stomach and duodenum
under both adult and child digestive conditions
Adult Child
Stomach Duodenum
Roussel et al., Ped. Res., 2016
TIM
ConclusionBiotic factorsIntroduction Abiotic factors
Adult Child Adult Child
Jejunum Ileum
At the middle of digestion :
Significant bacterial mortality in the jejunum and ileumbut only in adult
Roussel et al., Ped. Res., 2016
TIM
Results : effect of « age » on EHEC survival
ConclusionBiotic factorsIntroduction Abiotic factors
0157:H7Transit marker
At the end of digestion :
Significant bacterial growth in the jejunum and ileum, mostly in child
Roussel et al., Ped. Res., 2016
Adult Child Adult Child
Jejunum Ileum
13%
87%
21%
442%
TIM
Results : effect of « age » on EHEC survival
ConclusionBiotic factorsIntroduction Abiotic factors
0157:H7Transit marker
Results : EHEC physiological state
Ileal effluents : flow cytometry analysis
→ Higher number of altered cells under adult digestive conditions
Roussel et al., Ped. Res., 2016
ADULT
CHILD
T0 5%
viable
altereddead
Green fluorescence
Red
fluor
esce
nce
37% 38%
14% 15%
TIM
ConclusionBiotic factorsIntroduction Abiotic factors
viable
altereddead
Green fluorescence
Red
fluor
esce
nce
→ Higher number of viable cells under child digestive conditions
→ Bacterial growth as previously observed by numeration
Roussel et al., Ped. Res., 2016
ADULT
CHILD
T0
77%
9% 6%
22% 34%TIM
ConclusionBiotic factorsIntroduction Abiotic factors
Results : EHEC physiological state
A higher number of cells, in a better physiological state,
is likely to reach the terminal ileum and colon under child conditions
→ main sites of EHEC pathogenesis
Results : EHEC survival and physiological state
Chong et al., Microbiol., 2007Lewis et al., Infect. Immun., 2015
ConclusionBiotic factorsIntroduction Abiotic factors
Results : effect on « age » on stx expression
stx1 stx2
adult
child
Gastric effluents
In the gastric effluents :
stx1 and stx2 encoding Shigatoxins are significantly overexpressed
under child conditions compared to adult ones
Roussel et al., Ped. Res., 2016
RTqPCR(stx)
TIM
ConclusionBiotic factorsIntroduction Abiotic factors
stx1 stx2
Ileal effluents
In the ileal effluents :
similar trends are observed for stx but less obvious than in the stomach
Roussel et al., Ped. Res., 2016
Results : effect on « age » on stx expressionadult
child
RTqPCR(stx)
ConclusionBiotic factorsIntroduction Abiotic factors
adult
child
Stx production
Ileal effluents
Adult : no toxin was detected
Child: regular increase in the amount of Stx produced
Roussel et al., Ped. Res., 2016
Results : effect of « age » on Stx production
TIM
ELISA (Stx)
ConclusionBiotic factorsIntroduction Abiotic factors
Results : effect on « age » of stx expression and production
stx expression and production higher under child vs adult digestive conditions
→ Stx : main virulence factor of EHEC, responsible for systemic complications
ConclusionBiotic factorsIntroduction Abiotic factors
eae gene encoding intimin overexpressed :
→ under adult conditions at the beginning of digestion
Roussel et al., Ped. Res., 2016
RTqPCR(eae)
Results : effect of « age » on eae expression
Ileal effluentsGastric effluents
adult
child
ConclusionBiotic factorsIntroduction Abiotic factors
eae gene encoding intimin overexpressed :
→ under child conditions at the end of digestion
Roussel et al., Ped. Res., 2016
Results : effect of « age » on eae expression
Ileal effluentsGastric effluents
adult
child
ConclusionBiotic factorsIntroduction Abiotic factors
RTqPCR(eae)
Overexpression of adhesin under child conditions
→ most of bacteria have reached the distal parts of the small intestine→ main site of EHEC colonization
Roussel et al., Ped. Res., 2016
Results : effect of « age » on eae expression
Ileal effluentsGastric effluents
adult
child
ConclusionBiotic factorsIntroduction Abiotic factors
RTqPCR(eae)
PHYSICO-CHEMICALPARAMETERS
INTESTINALMICROBIOTA
ABIOTIC FACTORS BIOTIC FACTORS
ConclusionBiotic factorsIntroduction Abiotic factors
Differences in the physico-chemical parameters of the upper human GIT
→ partially explain why child are more susceptible to EHEC infections than adults
Concluding remarks
StomachShiga toxin production
+++
ConclusionBiotic factorsIntroduction Abiotic factors
Small Intestine
Bacterial growth
+++Shiga toxin production
+
StomachShiga toxin production
+++
ConclusionBiotic factorsIntroduction Abiotic factors
Small Intestine
Bacterial growth
+++
M cell
Shiga toxin production
+
StomachShiga toxin production
+++
Intestinal epithelium
Adhesin expression
++
ConclusionBiotic factorsIntroduction Abiotic factors
Small Intestine
Bacterial growth
+++
M cell
Shiga toxin production
+
StomachShiga toxin production
+++
Intestinal epithelium
Adhesin expression
++Gb 3
KidneysGb3 expression
Chaisri et al., Microb. Pathog., 2001
ConclusionBiotic factorsIntroduction Abiotic factors
PHYSICO-CHEMICALPARAMETERS
INTESTINALMICROBIOTA
ABIOTIC FACTORS BIOTIC FACTORS
ConclusionAbiotic factors
Impact of Abiotic and Biotic Parameters of the Human Gut
on EHEC Survival and Virulence
Introduction Biotic factors
IN VITRO AND IN VIVO COMPLEMENTARYAPPROACHES
TIM : humanupper GIT
1 2 4
ARCOL : humanlower GIT
ConclusionAbiotic factorsIntroduction Biotic factors
IN VITRO IN VIVO
3
MICE ILEAL LOOPS : interactions with
intestinal epithelium
GNOTOBIOTIC RATS : interactions with gut
microbiota
IN VITRO AND IN VIVO COMPLEMENTARYAPPROACHES
TIM : humanupper GIT
1 2 4
ARCOL : humanlower GIT
ConclusionAbiotic factorsIntroduction Biotic factors
IN VITRO IN VIVO
3
MICE ILEAL LOOPS : interactions with
intestinal epithelium
GNOTOBIOTIC RATS : interactions with gut
microbiota
Experimental plan1
TIMhealthy adult
Western diet
O157:H7 EDL 933(2.105 CFU/mL)
+ S. cerevisiae CNCM I-3856 (107 CFU/mL)
O157:H7 EDL 933(2.105 CFU/mL)
Digestive compartmentsn = 4
LB medium
SURVIVAL
ConclusionAbiotic factorsIntroduction Biotic factors
Bacterial mortality in the stomach and duodenumProbiotic → EHEC survival unchanged
E. coli O157:H7
E. coli O157:H7 + S. cerevisiae
Transit marker
0
20
40
60
80
100
120
0 30 60 90 120 150
Via
ble
cel
ls(%
of
inta
ke)
Time of digestion (min)
Stomach
*
* * *
†
†
††
† 0
1
2
3
4
5
6
7
30 60 120 180 240
Via
ble
cel
ls(%
of
inta
ke)
Time of digestion (min)
Duodenum
*
* †
††
*
Etienne-Mesmin et al., Appl. Environ. Microbiol., 2011
Results : EHEC survival1
ConclusionAbiotic factorsIntroduction Biotic factors
Significant reduction of bacterial growth in the jejunum and ileum→ competition for nutrients?
→ production of inhibitory compounds?
0
10
20
30
40
50
60
60 120 180 240 300
Via
ble
cel
ls(%
of
inta
ke)
Time of digestion (min)
Jejunum
** †
*
*
*
†
†
+++
++
0
10
20
30
40
50
60
70
80
60 120 180 240 300
Via
ble
cel
ls(%
of
inta
ke)
Time of digestion (min)
Ileum*
*
*
†
†
++
Etienne-Mesmin et al., Appl. Environ. Microbiol., 2011
1 Results : EHEC survivalE. coli O157:H7
E. coli O157:H7 + S. cerevisiae
Transit marker
ConclusionAbiotic factorsIntroduction Biotic factors
Significant higher concentrations of ethanol with probiotic yeasts→ toxic for cell membrane? Chiou et al., Appl. Environ. Microbiol., 2004
→ synergetic action with other inhibitory compounds?
0
10
20
30
40
50
60
70
80
60 120 180 240 300
Via
ble
cel
ls(%
of
inta
ke)
Time of digestion (min)
Ileum*
*
*
†
†
++
E. coli O157:H7
E. coli O157:H7 + S. cerevisiae
Transit marker
0
10
20
30
40
50
60
60 120 180 240 300
Via
ble
cel
ls(%
of
inta
ke)
Time of digestion (min)
Jejunum
** †
*
*
*
†
†
+++
++
Etienne-Mesmin et al., Appl. Environ. Microbiol., 2011
1 Results : ethanol production
ConclusionAbiotic factorsIntroduction Biotic factors
Ethanol
IN VITRO AND IN VIVO COMPLEMENTARYAPPROACHES
TIM : humanupper GIT
1 2 4
ARCOL : humanlower GIT
ConclusionAbiotic factorsIntroduction Biotic factors
IN VITRO IN VIVO
3
MICE ILEAL LOOPS : interactions with
intestinal epithelium
GNOTOBIOTIC RATS : interactions with gut
microbiota
COLON
Human colonic model
ARCOLARtificial COLon
Blanquet-Diot et al., Pharm. Res., 2012Cordonnier et al., Microorganisms, 2015
SIMULATED PARAMETERS
Inoculation with freshhuman fecal samples :
complex and metabolicallyactive microbiota
Body temperature
Mean colonic pH
Retention time
Anaerobiosis
(sustained by the sole activityof the microbiota)
Passive absorption(dialysis)
Redox potential
ARCOL
ConclusionAbiotic factorsIntroduction Biotic factors
Experimental plan2
ARCOL
n = 3 with three different healthy donors
ConclusionAbiotic factorsIntroduction Biotic factors
1) Control experiment2) S. cerevisiae3) O157:H74) S. cerevisiae + O157:H7
Experimental plan2
ARCOL
ARCOL
D0 D4 D8 D12
STABILISATION
Inoculation of the bioreactorwith fecal sample
1) Control experiment2) S. cerevisiae3) O157:H74) S. cerevisiae + O157:H7
n = 3 with three different healthy donors
ConclusionAbiotic factorsIntroduction Biotic factors
Experimental plan2
ARCOL
ARCOL
D0 D4 D8
STABILISATION S. cerevisiae CNCM-I 3856
S. cerevisiae CNCM I-3856107 CFU/mLTwice daily administration
D12
Inoculation of the bioreactorwith fecal sample
1) Control experiment2) S. cerevisiae3) O157:H74) S. cerevisiae + O157:H7
n = 3 with three different healthy donors
ConclusionAbiotic factorsIntroduction Biotic factors
Experimental plan2
ARCOL
ARCOL
D0 D4 D8
STABILISATION
D12
Inoculation of the bioreactorwith fecal sample
Gastric and smallintestinal stresses
O157:H7 EDL 933107 UFC/mL
1) Control experiment2) S. cerevisiae3) O157:H74) S. cerevisiae + O157:H7
n = 3 with three different healthy donors
ConclusionAbiotic factorsIntroduction Biotic factors
Experimental plan2
ARCOL
ARCOL
D0 D4 D8
STABILISATION S. cerevisiae CNCM-I 3856
S. cerevisiae CNCM I-3856107 CFU/mL
Twice daily administration
D12
Inoculation of the bioreactorwith fecal sample
Gastric and smallintestinal stresses
O157:H7 EDL 933107 UFC/mL
1) Control experiment2) S. cerevisiae3) O157:H74) S. cerevisiae + O157:H7
n = 3 with three different healthy donors
ConclusionAbiotic factorsIntroduction Biotic factors
Experimental plan2
ARCOL
1) Control experiment2) S. cerevisiae3) O157:H74) S. cerevisiae + O157:H7
SURVIVAL VIRULENCE INTERACTION WITHGUT MICROBIOTA
Composition of gut microbiotaqPCR
Metabolic activitySCFA (GC)
qPCR qRT-PCRstx / eae
ConclusionAbiotic factorsIntroduction Biotic factors
2
ARCOL
Time post-administration (days)
Transit markerO157:H7
Surv
ival
of O
157:
H7
(% o
f int
ake)
No colonization by O157:H7 of the human simulated colonic environment→ in accordance with the rapid elimination
from feces of HUS patients Tarr et al., J. Infect. Dis., 1990
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
qPCREHEC
Results : EHEC survival
ConclusionAbiotic factorsIntroduction Biotic factors
No influence of the probiotic yeaston the survival of the pathogen in the in vitro colon
Time post-administration (days)
Surv
ival
of O
157:
H7
(% o
f int
ake)
Transit markerO157:H70157:H7 (with probiotic)
Thévenot et al., Appl. Microbiol. Biotechnol., 2015Thévenot et al., Appl. Environ. Microbiol., 2013
2 Results : effect of S. cerevisiae on EHEC survival
qPCREHEC
ARCOL
ConclusionAbiotic factorsIntroduction Biotic factors
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
BacteroidetesFirmicutesActinobacteria
BacteroidesLactococcus/Pediococcus/LeuconostocEnterobacteriaceae
Yeast_2_12Yeast_2_10
Yeast_2_11
Yeast_2_9Yeast_3_12
Yeast_1_12Yeast_1_10
Yeast_1_9Yeast_3_11
Yeast_3_10Yeast_3_9
Yeast and EHEC_2_11Yeast and EHEC_2_9
Yeast and EHEC_2_10Yeast and EHEC_2_12
Yeast and EHEC_1_10Yeast and EHEC_1_11
Yeast and EHEC_1_12Yeast and EHEC_1_9
EHEC_1_12EHEC_1_9
EHEC_1_10EHEC_1_11
Yeast and EHEC_3_9Yeast and EHEC_3_10Yeast and EHEC_3_11
Yeast_1_11
Yeast and EHEC_3_12Control_1_12
Control_2_11Control_2_12
Control_1_10Control_1_9
Control_3_12Control_3_9
Control_3_10
Control_3_11Control_1_11
Control_2_10Control_2_9
EHEC_3_10
EHEC_3_11EHEC_3_12
EHEC_2_12EHEC_2_10EHEC_2_11
EHEC_2_9EHEC_3_9
0.0 0.5 1.0 1.5
Agglomerativehierarchical clustering
2
qPCRgut microbiota
Results : composition of gut microbiota
ARCOL
ConclusionAbiotic factorsIntroduction Biotic factors
Control= 3 donors
1
2
3
Yeast_2_12Yeast_2_10
Yeast_2_11
Yeast_2_9Yeast_3_12
Yeast_1_12Yeast_1_10
Yeast_1_9Yeast_3_11
Yeast_3_10Yeast_3_9
Yeast and EHEC_2_11Yeast and EHEC_2_9
Yeast and EHEC_2_10Yeast and EHEC_2_12
Yeast and EHEC_1_10Yeast and EHEC_1_11
Yeast and EHEC_1_12Yeast and EHEC_1_9
EHEC_1_12EHEC_1_9
EHEC_1_10EHEC_1_11
Yeast and EHEC_3_9Yeast and EHEC_3_10Yeast and EHEC_3_11
Yeast_1_11
Yeast and EHEC_3_12Control_1_12
Control_2_11Control_2_12
Control_1_10Control_1_9
Control_3_12Control_3_9
Control_3_10
Control_3_11Control_1_11
Control_2_10Control_2_9
EHEC_3_10
EHEC_3_11EHEC_3_12
EHEC_2_12EHEC_2_10EHEC_2_11
EHEC_2_9EHEC_3_9
0.0 0.5 1.0 1.5
BacteroidetesFirmicutesActinobacteria
BacteroidesLactococcus/Pediococcus/LeuconostocEnterobacteriaceae
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
2
qPCRgut microbiota
Results : composition of gut microbiota
ARCOL
ConclusionAbiotic factorsIntroduction Biotic factors
Yeast_2_12Yeast_2_10
Yeast_2_11
Yeast_2_9Yeast_3_12
Yeast_1_12Yeast_1_10
Yeast_1_9Yeast_3_11
Yeast_3_10Yeast_3_9
Yeast and EHEC_2_11Yeast and EHEC_2_9
Yeast and EHEC_2_10Yeast and EHEC_2_12
Yeast and EHEC_1_10Yeast and EHEC_1_11
Yeast and EHEC_1_12Yeast and EHEC_1_9
EHEC_1_12EHEC_1_9
EHEC_1_10EHEC_1_11
Yeast and EHEC_3_9Yeast and EHEC_3_10Yeast and EHEC_3_11
Yeast_1_11
Yeast and EHEC_3_12Control_1_12
Control_2_11Control_2_12
Control_1_10Control_1_9
Control_3_12Control_3_9
Control_3_10
Control_3_11Control_1_11
Control_2_10Control_2_9
EHEC_3_10
EHEC_3_11EHEC_3_12
EHEC_2_12EHEC_2_10EHEC_2_11
EHEC_2_9EHEC_3_9
0.0 0.5 1.0 1.5
BacteroidetesFirmicutesActinobacteria
BacteroidesLactococcus/Pediococcus/LeuconostocEnterobacteriaceae
O157:H7 1
S. cerevisiae
S. cerevisiae
1
2
3
O157:H7 + S. cerevisiae
O157:H7 + S. cerevisiae
1
2
O157:H7 + S. cerevisiae
3
O157:H7 2
3
Control= 3 donors
1
2
3
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
2
qPCRgut microbiota
Results : composition of gut microbiota
ARCOL
ConclusionAbiotic factorsIntroduction Biotic factors
BacteroidetesFirmicutesActinobacteria
BacteroidesLactococcus/Pediococcus/LeuconostocEnterobacteriaceae
Individual-dependant effect of pathogen and probioticon the human gut microbiota
→ clinical course of EHEC infections? Pifer and Sperandio, Microbiol. Spectrum, 2014
→ efficacy of probiotic treatment? Thevenot et al., Appl. Microbiol. Biotechnol., 2015
2
qPCRgut microbiota
Results : composition of gut microbiota
ARCOL
ConclusionAbiotic factorsIntroduction Biotic factors
*
*
*
* *
During in vitro EHEC infectionProbiotic → ↑ acetate and ↓ butyrate
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
2
GCSCFA
Results : metabolic activity of gut microbiota
ARCOL
ConclusionAbiotic factorsIntroduction Biotic factors
*
*
*
* *
↑ Acetate↓ Shiga toxin gene expressionAshara et al., Infect. Immun., 2004
Fukuda et al., Nature, 2011
↑ Butyrate↑ A/E gene expression
Tobe et al., Infect. Immun., 2011
During in vitro EHEC infectionProbiotic → ↑ acetate and ↓ butyrate
→ Beneficial modulation of SCFA production
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
2
GCSCFA
Results : effect of S. cerevisiae on metabolic activity
ConclusionAbiotic factorsIntroduction Biotic factors
ARCOL
x 9
x 3 x 3
Shiga toxins
Time post-administration (hours)
Intimin
Until 12h post-infectionOverexpression of major virulence genes : Shiga toxins, intimin
→ even if the in vitro colonic environment is devoid of epithelial cells
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
stx1 stx2 eae
2
RT-qPCRstx, eae
ARCOL
Results : EHEC virulence
ConclusionAbiotic factorsIntroduction Biotic factors
Shiga toxins
Time post-administration (hours)
Intimin
At 9h and 12h post-infectionProbiotic → significant reduction in stx1 and stx2 mRNA levels
→ due to the increase in acetate production?
stx1 stx2 eae
2
RT-qPCRstx, eae
Results : effect of S. cerevisiae on EHEC virulence
ARCOL
ConclusionAbiotic factorsIntroduction Biotic factors
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
IN VITRO AND IN VIVO COMPLEMENTARYAPPROACHES
TIM : humanupper GIT
1 2 4
ARCOL : humanlower GIT
ConclusionAbiotic factorsIntroduction Biotic factors
IN VITRO IN VIVO
3
MICE ILEAL LOOPS : interactions with
intestinal epithelium
GNOTOBIOTIC RATS : interactions with gut
microbiota
Euthanasia
Axenic ratsHuman microbiota-associated rats
D15
CAECAL CONTENTS CENTRIFUGED/FILTRATED
Inoculation with O157:H7 EDL 933
TRANSCRIPTOMIC ANALYSIS (DNA MICROARRAY)
n = 8 n = 8
ConclusionAbiotic factorsIntroduction Biotic factors
Experimental plan3
D15
Caecal contents
Humanized ratsAxenic rats
Results : effect of microbiota on EHEC gene expression
669 repressed genes 408 activated genes
Human intestinal microbiota : modulation of ~ 20 % of O157:H7 EDL 933 genes
Le Bihan et al., Microb. Infect., 2015
ConclusionAbiotic factorsIntroduction Biotic factors
3
VIRULENCE GENES
Intestinal microbiota : repression of LEE encoding-genes involved in the intimate adhesion
of EHEC to the intestinal epithelium
-8-6-4-202468
lldP
espZ
espA
espB tir ea
e
espJ
espM
2
nleG
nleA
fold
cha
nge
(HM
C /
GFC
)
Validation by qRT-PCR
Le Bihan et al., Microb. Infect., 2015
ConclusionAbiotic factorsIntroduction Biotic factors
D15
Caecal contents
Humanized ratsAxenic rats
Results : effect of microbiota on EHEC gene expression3
IN VITRO AND IN VIVO COMPLEMENTARYAPPROACHES
TIM : humanupper GIT
1 2 4
ARCOL : humanlower GIT
ConclusionAbiotic factorsIntroduction Biotic factors
IN VITRO IN VIVO
3
MICE ILEAL LOOPS : interactions with
intestinal epithelium
GNOTOBIOTIC RATS : interactions with gut
microbiota
D0 D7
Daily oral administration ofS. cerevisiae CNCM I-3856 (2.106 CFU)
or saline water (control group)
Sacrifice of mice5 h post-infection
MICE ILEAL LOOPS
Injection of O157:H7 EDL 933Gastric and smallintestinal stresses
Intracellular bacteria
Peyer’s patches Mucosa
(107 CFU/mL)
Experimental plan4
n = 26
ConclusionAbiotic factorsIntroduction Biotic factors
D0 D7
Mice ileal loops
Oral administration of S. cerevisiae
Peyer’s PatchesIn
tra
cellu
lar
O1
57
:H7
(lo
g1
0C
FU
/g o
f Pe
yer’
sP
atc
he
s)
Mucosa
Intr
ace
llula
rO
15
7:H
7(l
og
10
CF
U/g
of m
uco
sa)
Specific inhibition of EHEC O157:H7 interactionswith Peyer’s Patches
→ Physical interactions between EHEC and probiotic→ Competition for cell receptor?
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
4 Results : effect of S. cerevisiae on interactions with PPs
ConclusionAbiotic factorsIntroduction Biotic factors
Pe
rce
nta
ge
of
He
mo
rrh
ag
icP
eye
r’s
Pa
tch
es
Significant decreasein the number of
hemorrhagic Peyer’s Patches
Thévenot et al., Appl. Microbiol. Biotechnol., 2015
4
D0 D7
Mice ileal loops
Oral administration of S. cerevisiae
Non hemorrhagic Hemorrhagic
Results : effect of S. cerevisiae on hemorrhagic PPs
ConclusionAbiotic factorsIntroduction Biotic factors
PHYSICO-CHEMICALPARAMETERS
INTESTINALMICROBIOTA
ABIOTIC FACTORS BIOTIC FACTORS
Concluding remarks (1)
ConclusionAbiotic factorsIntroduction Biotic factors
Individual-dependant effect of EHEC on human gut microbiota compositionInfluence of intestinal microbiota on EHEC virulence gene expression
Role of gut microbiota in clinical course of EHEC infections ?
PHYSICO-CHEMICALPARAMETERS
INTESTINALMICROBIOTA
ABIOTIC FACTORS BIOTIC FACTORS
Concluding remarks (2)
ConclusionAbiotic factorsIntroduction Biotic factors
Complementary in vitro and in vivo approaches
→ S. cerevisiae CNCM I-3856: promising antagonistic effects against EHEC O157:H7
Small Intestine
Bacterial growth
S. cerevisiae CNCM-I 3856
ConclusionAbiotic factorsIntroduction Biotic factors
Small Intestine
Bacterial growth
Peyer’s Patches
Tropism to Peyer’s Patches
S. cerevisiae CNCM-I 3856
ConclusionAbiotic factorsIntroduction Biotic factors
Small Intestine
Bacterial growth
Shiga toxin expression
Peyer’s Patches
Tropism to Peyer’s Patches
S. cerevisiae CNCM-I 3856
Large intestine
a
ConclusionAbiotic factorsIntroduction Biotic factors
Small Intestine
Bacterial growth
Shiga toxin expression
Peyer’s Patches
Tropism to Peyer’s Patches
S. cerevisiae CNCM-I 3856
Large intestine
↑ ACETATE
↓ BUTYRATEa
ConclusionAbiotic factorsIntroduction Biotic factors
Small Intestine
Bacterial growth
Shiga toxin expression
Peyer’s Patches
Tropism to Peyer’s Patches
S. cerevisiae CNCM-I 3856
Large intestine
↑ ACETATE
↓ BUTYRATE
?
a
ConclusionAbiotic factorsIntroduction Biotic factors
ABIOTIC FACTORSpHBile et digestive enzymesTransit time…
BIOTIC FACTORSIntestinal Microbiota
ProbioticsSURVIVAL / PHYSIOLOGICAL STATE
VIRULENCE
INTERACTION WITH INTESTINAL EPITHELIUM
ConclusionAbiotic factorsIntroduction Biotic factors
EHEC AND DIGESTIVE ENVIRONMENT
Conclusion
Temporal/spacial modulations of food-borne pathogen survival and virulence
in the human GIT
Abiotic factorsIntroduction Biotic factors
Dynamic multi-compartmental in vitro models
GI parameters
ABIOTICpH, enzymes, bile
fluid shearoxygenation
BIOTICresident microbiota
probiotics
Bacteria
strainculture conditions
growth phase
Other parameters
food matrixfood process…
Dynamic multi-compartmental in vitro models
Temporal/spacial modulations of food-borne pathogen survival and virulence
in the human GIT
ConclusionAbiotic factorsIntroduction Biotic factors
Thank you for your attention !
Alric MoniqueBernalier-Donadille AnnickChalancon SandrineCordonnier CharlotteDenis Sylvain Jubelin GrégoryLe Goff OlivierRoussel CharlèneThévenot Jonathan
Galia WessamLeriche FrançoiseDelphine Thevenot-Sergentet
Tom Van de Wiele
Cordonnier CharlotteLivrelli ValérieNguyen HangRougeron AmandineThévenot Jonathan
Harel JoséeLe Bihan Guillaume
Ballet NathalieVandekerckove Pascal
Valérie Livrelli
Delphine Thévenot-Sergentet
Grégory Jubelin