1

Gut Microbes and

Irritable Bowel Syndrome

Mark Pimentel, MD, FRCP(C)

Director, GI Motility Program

Cedars-Sinai Medical Center

2

STRATEGY 1: Treat the CAUSE

DYSMOTILITY

ACUTE

GASTROENTERITIS

S

I

B

O

SEROTONIN

IBS

BRAIN-GUT AXIS

Salmonella, E. coli,

Campylobacter, …

Agonist/Antagonist

3

SIBO- What Is It?

1011cfu/mL

103 cfu/mL

102 cfu/mL

Colon

Small Bowel

101 cfu/mL

~ 0 cfu/mL Duodenum

Cecum

Jejunum

Ileum

4

Diagnosis of SIBO

Type of Test Specific Test

Breath testing Lactulose Breath Test

13C Xylose Breath Test

Glucose Breath Test

Sucrose Breath Test

Sorbitol Breath Test

Culture Small bowel aspirate and culture

Empiric Approach Test, treat and re-evaluate

5

Lactulose Breath Test

0

10

20

30

40

50

60

70

0 15 30 45 60 75 90 105 120 135 150 165 180

Part

s P

er

Millio

n

Time (Minutes)

6

4.46 (1.69, 11.80)

20.67 (5.29, 80.69)

0.25 (0.06, 1.00)

18.04 (6.55, 49.71)

24.27 (7.35, 80.15)

10.89 (3.52, 33.71)

2.29 (0.89, 5.87)

0.49 (0.18, 1.33)

1.26 (0.38, 4.20)

4.30 (1.24, 14.98)

12.38 (1.65, 92.66)

16.28 (0.82, 321.37)

Breath Testing in IBS

Forest plot of all studies comparing breath testing in

IBS subjects with healthy controls

OR=odds ratio

Shah ED et al. Dig Dis Sci. 2010;55:241-249.

NOTE: Weights are from random effects analysis

Overall (I-squared = 84.6%, P= 0.0001)

Author

Pimentel

Walters

Collin

Scarpellini

Lupascu

Grover

Bratten

Skoog

Parodi

Rana

Galatola

Breath Test

lactulose

lactulose

lactulose

lactulose

glucose

sucrose

lactulose

fructose

glucose

glucose

xylose

Type of

OR (95% CI)

100.00

Weight

9.21

9.10

10.02

9.61

9.76

10.17

10.03

9.58

9.48

7.58

5.46

%

1 .1 .2 .5 1 2 5 10 20

7

Breath Testing in IBS

Forest plot of all age-sex matched studies

NOTE: Weights are from random

effects analysis

Overall (I-squared = 67.9%, P=.008)

Parodi

Scarpellini

Lupascu

Author

Collin

Pimentel

Grover

glucose

lactulose

glucose

Breath Test

lactulose

Type of

lactulose

sucrose

9.64 (4.26, 21.82)

4.30 (1.24, 14.98)

24.27 (7.35, 80.15)

10.89 (3.52, 33.71)

OR (95% CI)

18.04 (6.55, 49.71)

20.67 (5.29, 80.69)

2.29 (0.89, 5.87)

100.00

15.71

16.20

16.82

Weight

17.94

%

14.68

18.65

1 .1 .2 .5 1 2 5 10 20

OR=odds ratio

Shah ED et al. Dig Dis Sci. 2010;55:241-249.

8

PPI and SIBO

PPI=proton pump inhibitor; PPM=part per million

Law D et al. Dig Dis Sci. 2010;55:2302-2308.

Parameter Non-PPI

N=449

PPI

(n=106) P-value

Δ20 ppm by 90 minutes¶ n (%) 253 (56.3) 49 (46.2) 0.07

Mean amplitude 45.5±27.0 53.0±38.5 0.20

≥20 ppm by 90 minutes‡ n (%) 281 (62.6) 64 (60.4) 0.74

Mean amplitude 49.9±28.6 51.6±38.5 0.73

≥20 ppm any time* n (%) 349 (77.7) 88 (83.0) 0.29

Mean amplitude 61.2±34.2 59.8±43.3 0.77

¶Subjects with ≥20 ppm rise in hydrogen production over baseline. ‡Subjects with any value of ≥20 ppm before 90 minutes.

*Subjects with hydrogen levels ≥20 ppm at any point during the 180 minute test.

9

PPI and SIBO

0

2

4

6

8

10

12

14

16

18

No-PPI PPI

% o

f su

bje

cts

pro

du

cin

g

meth

an

e

Law D et al. Dig Dis Sci. 2010;55:2302-2308.

10

1

10

100

1000

10000

100000

1000000

Healthy Celiac IBD IBS Billroth II

Co

lon

y C

ou

nts

per

mL

Culture of Small Bowel

IBD=inflammatory bowel disease; SIBO=small intestinal bacterial overgrowth

Khoshini R et al. Dig Dis Sci. 2008;53:1443-1454.

SIBO?

>105 is diagnostic of Billroth II

11

0

5

10

15

20

25

30

35

40

45

50

>10,000 coliforms >5,000 coliforms

Perc

en

t o

f S

ub

jects

Control

IBS

Small Bowel Culture in IBS

N=165 IBS, 26 controls

Posserud I et al. Gut. 2007;56:802-808.

4%

24%

12%

43%

P<.05 P<.001

12

N=112 IBS, 208 GI controls

*Number of subjects who have coliform counts greater than 103 cfu/mL

Pyleris E et al. Dig Dis Sci. 2012;57:1321-1329.

Small Bowel Culture in IBS

0

5

10

15

20

25

30

35

40

Perc

en

t o

f S

ub

jects

Non-IBS

IBS

9.6%

37.5%

P<.001 even after controlling for PPI

13

Small Bowel Culture in IBS

N=77 non-D-IBS, N=35 D-IBS

*Number of subjects who have coliform counts greater than 103 cfu/mL

Pyleris E et al. Dig Dis Sci. 2012;57:1321-1329.

0

10

20

30

40

50

60

70

Perc

en

t o

f S

ub

jects

Non- D-IBS

D-IBS

27.3%*

60%*

P=0.004

14

Complexities of Gas Production

0

10

20

30

40

50

60

70

0 15 30 45 60 75 90 105 120 135 150 165 180

Part

s P

er

Mil

lio

n

Time (Minutes)

Hydrogen

Producers

H2S

Producers

5H2→1H2S

Methane

Producers

4H2→1CH4

0

10

20

30

40

50

60

70

0 15 30 45 60 75 90 105 120 135 150 165 180

Part

s P

er

Milli

on

Time (Minutes)

Methane

Hydrogen

0

10

20

30

40

50

60

70

0 15 30 45 60 75 90 105 120 135 150 165 180 P

art

s P

er

Milli

on

Time (Minutes)

H2

H2

15

IBS Subgroup

(n=65)* Hydrogen Methane

Diarrhea 34 0

Constipation 19 12

Methane in IBS Subjects

OR=, CI=3.7-, p<0.0001.

*After excluding normal (n=17), no gas on LBT (n=4)

and subjects where C=D (n=15).

100 % of methane

CI=confidence interval; LBT=lactulose breath test; OR=odds ratio

Pimentel M et al. Am J Gastroenterol. 2003;98:412-419.

16

Methane in IBS Subjects

0

10

20

30

40

50

60

70

80

90

100

H2 CH4 and H2 CH4

% o

f p

ati

en

ts

Constipation

Diarrhea

X2=16.6, P<.001

Pimentel M et al. Am J Gastroenterol. 2003;98:412-419.

17

Methane and Constipation

OR=odds ratio

Kunkel D et al. Dig Dis Sci. 2011;56:1612-1618.

Meta-analysis of studies

NOTE: Weights are from random effects analysis

Overall (I-squared = 64.6%, p = 0.004)

Pimentel

Hwang

Pimentel

Majewski

Bratten

Attaluri

Fiedorek

Parodi

Peled

Author

2003

2009

2003

2007

2008

2009

1990

2009

1987

Year

3.51 (2.00, 6.16)

5.58 (2.22, 14.03)

47.67 (8.73, 260.41)

44.23 (2.48, 788.51)

1.81 (0.70, 4.67)

2.22 (1.14, 4.33)

3.70 (2.06, 6.66)

4.32 (1.60, 11.68)

1.89 (0.79, 4.51)

0.83 (0.20, 3.56)

OR (95% CI)

100.00

12.68

6.99

3.18

12.46

15.14

15.92

12.03

%

13.17

8.43

Weight

1 .1 .2 .5 1 2 5 10 20

18

Methane and Transit

Study Measure of Transit Controls Methane producers P-value

Stephen, et al Whole gut transit time

(hours) 48.6 ± 6.6 84.6 ± 11.7 P<.05*

Oufir, et al Whole gut transit time

(hours) 50 95.5 P<.05*

Morken, et al Whole gut transit time

(hours) 95 ± 8 141 ± 14 P<.005

Cloarec, et al Orocecal transit time

(minutes) 68 ± 24 111 ± 52 P<.005*

Rumessen, et al Orocecal transit time

(minutes) 60 75 P>.1

Soares, et al Colonic transit time (hours) 61 80.5 P<.05*

Levitt, et al Stool frequency

(bm/day)

1.11 ±

0.06 1.03 ± 0.08 P>.1

Chatterjee, et al Stool frequency

(bm/day)

1.96 ±

1.40 1.17 ± 0.86 P<.05

OR=odds ratio

Kunkel D et al. Dig Dis Sci. 2011;56:1612-1618.

19

Methane Slows Intestinal Transit

Pimentel M et al. Am J Physiol. 2006.

0

20

40

60

80

Room Air Methane

% M

ark

er

Reco

ve

ry n=5, P<.0001

69% mean slowing

of transit with CH4

20

Methanobrevibacter smithii

Kim D et al. Abstract presented at Digestive Disease Week, 2010.

Hydrogen Producing IBS Stool Methane Producing IBS Stool

21

Incidence of Post-infectious IBS

Author Follow Up PI-IBS %

McKendrick et al 1994 12m 12/38 31

Gwee et al 1999 3m 22/100 22

Neal et al, 1997 & 2003 6m

6yr

23/357

14/192

7

7.3

Thornley et al 2000 6m 9/93 9

Okhuysen, et al 2004 6m 6/60 10

Mearin et al, 2005 12m 24/271 10

PI=postinfectious

McKendrick MW et al. J Infect. 1994;29:1-3; Gwee KA et al. Gut. 1999;44:400-406;

Neal KR et al. BMJ. 1997;314:779-782; Dunlop SP et al. Gastroenterology. 2003;125:1651-1659;

Okhuysen PC et al. Am J Gastroenterol. 2004;99:1774-1778. Mearin F et al. Gastroenterology. 2005;129:98-104.

22

• Included 8 studies due to quality

• Average rate of IBS after gastroenteritis was 9.8%

• No evidence of publication bias

Meta-analysis of Post-infectious IBS

Halvorson HA et al. Am J Gastroenterol. 2006;101:1894-1899.

23

• Female

• Increased diarrhea during acute infection

• Younger patient with acute diarrhea

• Absence of vomiting

• Psychology

Risk Factors for PI-IBS

PI=postinfectious

Neal KR et al. Gut. 2002;51:410-413; Neal KR et al. BMJ. 1997;314:779-782;

Gwee KA et al. Gut. 1999;44:400-406; Dunlop SP et al. Gastroenterology. 2003;125:1651-1659

24

Characteristics of Acute Illness Identify Patients at Risk for PI-IBS

-2

0

2

4

6

8

10

Age

Female Diarrhea

>7 d

Bloody

Stools

Abdominal

Cramps Weight

Loss

>10 lbs

OR

fo

r IB

S A

fter

Acu

te G

astr

oen

teri

tis*

P=.029

P=.006

P=.013

P=.001

P=.0001

P=.000

*Identified from multiple logistic regression analysis from 2069 patients participating in the Walkerton Health Study.

Marshall JK et al. Gastroenterology. 2006;131:445-450.

25

Salmonella and PI-IBS

Mearin F et al. Gastroenterology. 2006;129:98-104.

Percent with IBS at 1

year Relative Risk (CI)

Irritable Bowel 12% 5.2 (2.7-9.8)

Non-ulcer dyspepsia 15% 7.8 (3.1-19.7)

Nausea was a risk factor for NUD

26

Could all IBS be Post-infectious?

Shah ED et al. Dig Dis Sci. 2011.

12%

8%

4%

0%

0 5 10 15 20

Year

Steady-state = 9.1%

Pre

va

len

ce

27

NORMAL

ACUTE GASTROENTERITIS

COMPLETE

RECOVERY

~GENETIC SUSCEPTIBILIITY

~ABNORMAL HOST RESPONSE

~TOXIN INTENSITY

FUNCTIONAL GI DISEASES?

90% 10%

28

Stool = Campy-

No Acute Gastroenteritis Stool = Campy+

Acute Gastroenteritis

3 Months After Recovery

Stool Consistency Evaluation

Bacterial Quantitation by RT-PCR of

Duodenum, Jejunum, Ileum

Stool = Campy-

Recovery

n=33 n=33 C. jejuni

RT-PCR=reverse transcriptase polymerase chain reaction

Pimentel M et al. Dig Dis Sci. 2008;53:982-989.

29

Gastroenteritis and SIBO

0

5

10

15

20

25

30

35

40

45

50

Duodenum Jejunum ileum Total

Perc

en

t o

f ra

ts w

ith

SIB

O

27%

21%

17%

6.7%

3 months after Campylobacter jejuni 81-176 infection

Pimentel M et al. Dig Dis Sci. 2008;53:982-989.

30

Features of Rat Model

Persistent altered

stool consistency

Increased rectal

lymphocytes

0

2

4

6

8

10

12

C- C+/SIBO- C+/SIBO+

Recta

l L

ym

ph

oc

yte

s

P=.84

P<.01

0

20

40

60

80

100

C- C+/SIBO- C+/SIBO+ %

in

Rats

P<.001

P<.01

Pimentel M et al. Dig Dis Sci. 2008;53:982-989.