Table 1.
SBSEC prevalence in the GIT in studies including healthy people and patients with gastrointestinal conditions sorted by year of publication.
| Country | Participant selection | Sample type | Sample set | Sample size | SBSEC prevalence (%) | Individual species detected | Isolation technique | Identification technique | References |
|---|---|---|---|---|---|---|---|---|---|
| USA | Patients selected for CRC, inflammatory bowel disease, non-colonic neoplasms, gastrointestinal disorders. Controls among hospital workers and patients with no apparent gastrointestinal disease | Rectal swabs | Controls | 105 | 11 | n.d. | Selective culturing | Phenotypic identification | Klein et al., 1977 |
| CRC patients | 63 | 56 | |||||||
| IBD | 25 | 28 | |||||||
| Non-colonic neoplasma | 21 | 19 | |||||||
| GID | 37 | 14 | |||||||
| UK | Hospital population in- and outpatients | Stool | Adults | 39 | 5 | n.d. | Selective culturing | Phenotypic identification | Noble, 1978 |
| Neonates | 21 | 24 | |||||||
| USA | Outpatients undergoing colonoscopy for suspected CRC and polyps | Stool | Stool before colonoscopy | 35 | 3 | n.d. | Selective culturing | Group D streptex | Norfleet and Mitchell, 1993 |
| Aspirated colon fluid | Aspirated colon fluid | 40 | 8 | ||||||
| Tissue biopsies | Normal remote | 40 | 0 | ||||||
| Normal adjacent | 40 | 0 | |||||||
| Adenoma | 33 | 3 | |||||||
| Carcinoma | 6 | 0 | |||||||
| UK | CRC cases matched to patients having surgery for benign disease or diagnostic colonoscopy | Stool | Control | 23 | 13 | n.d. | Selective culturing | Phenotypic identification | Potter et al., 1998 |
| CRC | 19 | 11 | |||||||
| Tissue samples | Control | 23 | 4 | ||||||
| Normal CRC | 19 | 5.5 | |||||||
| Tumor CRC | 19 | 11 | |||||||
| Blood | Control | 23 | 0 | ||||||
| CRC | 19 | 0 | |||||||
| Malaysia | CRC patients with (bac+) and without bacteremia (bac−) and controls in tumor (TU) and non-tumor (NTU) specimens | Stool | Control | 50 | 12 | 8% SGG | Selective culturing and DNA-based detection* | Phenotypic identification sodA gene PCR and qPCR | Abdulamir et al., 2010 |
| CRC bac− | 52 | 13 | 10% SGG | ||||||
| CRC bac+ | 39 | 13 | 10% SGG | ||||||
| Mucosal washes | Control | 50 | 6 | 4% SGG | |||||
| CRC bac− (TU) | 52 | 10 | 8% SGG | ||||||
| CRC bac− (NTU) | 52 | 6 | 4% SGG | ||||||
| CRC bac+ (TU) | 39 | 5 | 5% SGG | ||||||
| CRC bac+ (NTU) | 39 | 5 | 5% SGG | ||||||
| Tissue specimens | Control | 50 | 2 | 2% SGG | |||||
| CRC bac− (TU) | 52 | 17 | 17% (32.7%)*SGG | ||||||
| CRC bac− (NTU) | 52 | 12 | 12% (23.0%)*SGG | ||||||
| CRC bac+ (TU) | 39 | 21 | 21% (48.7%)*SGG | ||||||
| CRC bac+ (NTU) | 39 | 13 | 13% (35.9%)*SGG | ||||||
| Malaysia | Hospital population with CRC, inflammatory bowel disease and chronic gastrointestinal tract diseases (cases) and healthy individuals (controls) | Stool | Controls | 96 | 7 | n.d. | Selective culturing | Not described | Al-Jashamy et al., 2010 |
| IBD & chronic GID | 29 | 52 | |||||||
| CRC & adenoma | 41 | 46 | |||||||
| France | Colonoscopy patients. Not selected for disease | Stool | Normal colonoscopy | 134 | 6 | 0.4% SGG | Selective culturing | 16S rRNA gene | Chirouze et al., 2013 |
| Non-tumoral lesions | 76 | 1 | 0.7% SGP | ||||||
| Adenoma & carcinoma | 49 | 6 | 3.5% SL | ||||||
| Brazil | Colonoscopy patients in hospital | Rectal swab | Colonoscopy | 54 | 35 | 11% SGG | Culture-independent | qPCR targeting recN and gyrB | Lopes et al., 2014 |
| 13% SGP | |||||||||
| 20% SL | |||||||||
| 11% SII | |||||||||
| Israel | Colonoscopy patients. Acceptable indications for colonoscopy included screening for colorectal malignancy, postpolypectomy surveillance, and investigation of symptoms including hematochezia, abdominal pain, and change in bowel habits | Stool, aspirated colonic fluid and colonic tissue | Normal colonoscopy | 105 | 12 | n.d. | Selective culturing | VITEK2 | Boltin et al., 2015 |
| Non-advanced or advanced lesions | 13 | 15 | n.d. | ||||||
| South Africa | (Cohort 1) Patients with CRC without pre-selecting conditions | Tissue | Adenocarcinoma and adjacent normal | 55 | 0 | Not detected | Culture-independent | sodA gene qPCR | Viljoen et al., 2015 |
| (Cohort 2) Patients with sporadic microsatellite instability | Tissue | Adenocarcinoma | 18 | 0 | Not detected | ||||
| Spain | Unselected CRC patients | Matched tissue | Normal mucosa | 190 | 0 | Not detected | Culture-independent | sodA gene qPCR | Andres-Franch et al., 2017 |
| Tumor | 190 | 6 | 3% SGG | ||||||
| Germany | General population | Stool | Healthy controls | 99 | 63 | 63% SGG | Culture-independent | qPCR targeting recN | Dumke et al., 2017 |
| Kenya | Colonoscopy patients. Not selected for disease | Rectal swab | Normal colonoscopy | 193 | 14 | 8% SII | Selective culturing | 16S rRNA gene | Kaindi et al., 2017 |
| Adenomas & carcinomas | 80 | 22 | 22% SII | groEL sequencing | |||||
| USA | Tumor and normal adjacent tissue | Tissue | Adjacent normal | 128 | 47 | 47% SGG | Culture-independent | 16S rRNA gene qPCR | Kumar et al., 2017 |
| Carcinoma | 148 | 74 | 74% SGG |
bac+, patients with bacteremia; bac−, patients without bacteremia; GID, gastrointestinal disorders; IBD, inflammatory bowel disease; n.d., not determined; NTU, non-tumor tissue specimen; TU, tumor tissue specimen.