A Systematic Review: Fecal Bacterial Profile in Patients with Irritable Bowel Syndrome Analyzed with the GA-Map Dysbiosis Test Based on the 16S rRNA Gene of Bacterial Species or Groups

Figures & data

Table 1 Inclusion Criteria for Articles Included in the Systematic Review

Study, First Author, Year	Case-Control (IBS vs HC)	GA-map Dysbiosis Test	Samples of Feces	Adult Population	Written in English	Article Published 2015–2023	Article Available as a Full Article
Ahluwalia et al, 2021^Citation11	*	*	*	*	*	*	*
Casén et al, 2015^Citation10	*	*	*	*	*	*	*
Vasapolli et al, 2021^Citation12	*	*	*	*	*	*	*
Iribarren et al, 2022^Citation13	*	*	*	*	*	*	*
Mazzawi et al, 2018^Citation14	*	*	*	*	*	*	*

Table 2 Characteristics of Included Studies in the Systematic Review

			IBS patients					Controls
Study, first author, year	Country	Type of speci-men	IBS subtype	Age (years)	n partici-pants	Female/Males	DI^a	Age (years)	n partici-pants	Female/Males	DI^a	Micro-biome assess-ment method	Multiple compare-son correc-tion	Bacterial markers differ-rence with a significant P value < 0.05
Ahluwalia et al, 2021^Citation11	Sweden	Stool	IBS, IBS-D, IBS-M, IBS-C, IBS-U	Median (min-max) 52 (24–70)	40	31/9	No	Median(min-max) 26 (19–54)	18	9/9	No	GA-map Dysbiosis Test	NR^b	Yes
Casén et al, 2015^Citation10	Norway, Sweden, Denmark, Spain	Stool	IBS, IBS-D, IBS-C, IBS-M, IBS-U, IBS-A	Mean: 39	109	184/52	Yes	Mean (min-max) 41 (21–70)	43	187/110	Yes	GA-map Dysbiosis Test	NR^b	Yes
Vasapolli et al, 2021^Citation12	Germany	Stool	IBS-D, IBS-C	Mean (SD) IBS-D: 43.5 (20.6) IBS-C: 50.6 (18.2)	IBS-D: 15 IBS-C: 13	IBS-D: 10/5, IBS-C: 10/3	Yes	Mean (SD) 54.8 (11.2)	22	12/10	Yes	GA-map Dysbiosis Test (Lx)	Yes	Yes
Iribarren et al, 2022^Citation13	Sweden	Stool	IBS-D	Median (range) 31 (26–66)	9	6/3	No	Median (range) 22 (20–36)	7	5/2	No	GA-map Dysbiosis Test	NR^b	Yes
Mazzawi et al, 2018^Citation14	Norway	Stool	Mostly IBS-D	Mean (min-max) 32 (20–44)	13	4/9	Yes	Mean (min-max) 33 (20–42)	13	7/6	Yes	GA-map Dysbiosis Test	Yes	Yes

Notes: ^aDysbiosis Index, ^bNot reported.

Table 3 Quality of Each Study Included by Newcastle Ottawa Scale (NOS)

	Selection				Comparability		Exposure
Study, first author, year	(1) Is the case definition adequate? (ROME criteria)	(2) Represen-tativeness of the cases	(3) Selection of controls	(4) Definition of controls	(5) Compara-bility of baseline characteristics 1 (sex)	(6) Compara-bility of baseline characteristics 2 (age)	(7) Ascertain-ment of exposure	(8) Same method of ascertainment for cases and controls?	(9) Non-response rate
Ahluwalia et al, 2021^Citation11	*	*	*	*	*	IBS significantly older than HCs	*	*	Not relevant
Casén et al, 2015^Citation10	*	*	*	*	*	*	*	*	Not relevant
Vasapolli et al, 2021^Citation12	*	*	*	*	*	*	*	*	Not relevant
Iribarren et al, 2022^Citation13	*	*	NR^a	*	*	*	*	*	Not relevant
Mazzawi et al, 2018^Citation14	*	*	*	*	*	*	*	*	Not relevant

Note: ^aNot reported.

Figure 1 PRISMA flow diagram for depicting the literature search in PubMed (Medline) for this systematic review.

Table 4 Differences in Bacterial Markers Between IBS and IBS Subgroups and Healthy Controls (HCs)

	Increased in IBS vs HCs				Decreased in IBS vs HCs				No difference in IBS vs HCs
Study, first author, year	IBS	IBS-D	IBS-M	IBS-C	IBS	IBS-D	IBS-M	IBS-C	IBS	IBS-D	IBS-M	IBS-C
Ahluwalia et al, 2021^Citation11	Acinetobacter junii; Akkermansia muciniphila				Clostridum sp.
Casén et al, 2015^Citation10	NR^a
Vasapolli et al, 2021^Citation12										NS^b		NS^b
Iribarren et al, 2022^Citation13		Proteobacteria Pseudomonas spp.; Dorea spp.; Ruminococcus gnavus				Bacteroides pectinophilus
Mazzawi, 2018		Ruminococcus gnavus				Actinobacteria; Bifidobacteria

^aNot reported, ^bNon-significant.

Table 5 Dysbiosis Index in IBS and IBS Subgroups Compared to Healthy Controls (HCs)

	Increased in IBS vs HCs				Decreased in IBS vs HCs				No difference in IBS vs HCs
Study, first author, year	IBS	IBS-D	IBS-M	IBS-C	IBS	IBS-D	IBS-M	IBS-C	IBS	IBS-D	IBS-M	IBS-C
Ahluwalia, 2021	NR^a
Casén, 2015	73% (IBS) vs 16% (HCs) Mean: IBS: 2.98 HCs: 1.72	76% (IBS-D) vs 16% (HCs) Mean: IBS-D: 3.03 HCs: 1.72	67% (IBS-M) vs 16% (HCs) Mean: IBS-M: 3.33 HCs: 1.72	73% (IBS-C) vs 16% (HCs) Mean: IBS-C: 3.00 HCs: 1.72
Vasapolli, 2021									NS^b	NS^b		NS^b
Iribarren, 2022	NR^a
Mazzawi, 2018		Mean±SD: 4±0.5 (IBS) vs 2.6±0.2 (HCs)

Notes: ^aNot reported, ^bNon-significant.

Abbreviations: IBS, irritable bowel syndrome; IBS-D, diarrhea-predominant IBS; IBS-M, IBS with mix of diarrhea and constipation; IBS-C, constipation-predominant IBS; HCs, healthy controls; DI, dysbiosis index; NOS, Newcastle Ottawa Scale; PRISMA, preferred reporting items for systematic reviews and meta-analysis; NR, not reported; NS, non-significant.

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