Molecular identification of enterotoxigenic Bacteroides fragilis and the Distribution 16S rRNA gene, bft gene subtypes and gyrb gene in Iraqi patients with diarrhea

Main Article Content

Hussein Ali Khaleefah
Ashwak Basim Jasim
Saher Gazi Omeran


Molecular, Gene, Diarrhea


This study includes 50 stool: 21 patients with diarrhea and 29 healthy control samples were collected from different hospitals in Baghdad city (Baghdad teaching hospital, AL-yarmok teaching hospital and Pediatric teaching Hospital at the beginning of March/2020 to the end April/2021 . DNA was extracted directly from stool specimens and conventional PCR targeting 16S rRNA gene gyrb gene
used for B.fragilis detection, Bacteroides fragilis toxin (bft) gene used for detection of ETBF. The results showed that presence of 16S rRNA gene was detected in 17(32%) stool samples included 7(41.17%) of patients and 10 (58.8%) of control group . Presence of gyrb gene was detected in 9(52.9%) stool samples included 4 (44.4%)of patients and 5 (55.5%) of control group: the incidence of bft gene in 4(23.5%) stool samples included : 3 of patients and 1 control .bft2 and bft3 were found in 1 and 2 samples from 3 diarrheic patients with ETBF respectively.bft1 present in one sample in control group.

Abstract 147 | pdf Downloads 121


1. Lozupone, C. A.; Stombaugh, J. I.; Gordon, J. I.; Jansson, J. K. and Knight, R. (2012). Diversity, stability and resilience of the human gut microbiota. Nature, 489(7415): 220-230.
2. Gilbert, J. A.; Blaser, M. J.; Caporaso, J. G.; Jansson, J. K.; Lynch, S. V. and Knight, R. (2018). Current understanding of the human
microbiome. Nature medicine, 24(4): 392-400.
3. Zhang, L. and Shay, J. W. (2017). Multiple roles of APC and its therapeutic implications in colorectal cancer. JNCI: Journal of the
National Cancer Institute, 109(8).
4. Chung, L.; Orberg, E. T.; Geis, A. L.; Chan, J. L.; Fu, K.; Shields, C. E. D.; ... and Housseau, F. (2018). Bacteroides fragilis toxin coordinates a pro-carcinogenic inflammatory cascade via targeting of colonic epithelial cells. Cell host & microbe, 23(2): 203-214.
5. Meggersee, R. and Abratt, V. 2015. The occurrence of antibiotic resistance genes in drug resistant Bacteroides fragilis isolates from Groote
Schuur Hospital, South Africa. Anaerobe, 32: 1-6.
6. Wick, E. C. and Sears, C. L. 2010. Bacteroides spp. and diarrhea. Current opinion in infectious diseases, 23(5): 470.
7. Nguyen, T. V.; Le Van, P.; Le Huy, C. and Weintraub, A. (2005). Diarrhea caused by enterotoxigenic Bacteroides fragilis in children less than 5 years of age in Hanoi, Vietnam. Anaerobe, 11(1-2): 109-114.
8. Ulger Toprak, N.; Yagci, A.; Gulluoglu, B. M.; Akin, M. L.; Demirkalem, P.; Celenk, T. and Soyletir, G. (2006). A possible role of Bacteroides fragilis enterotoxin in the aetiology of colorectal cancer. Clinical microbiology and infection, 12(8): 782-786.
9. Myers, L. L; Firehammer, B. D.; Shoop, D. S. and Border, M. M. (1984). Bacteroides fragilis: a possible cause of acute diarrheal disease in
newborn lambs. Infection and immunity, 44(2): 241-244.
10. Sears, C. L.; Islam, S.; Saha, A.; Arjumand, M.; Alam, N. H.; Faruque, A. S. G. and Sack, R. B. 2008. Association of enterotoxigenic Bacteroides
fragilis infection with inflammatory diarrhea. Clinical Infectious Diseases, 47(6): 797-803.
11. Tong, J.; Liu, C.; Summanen, P. Xu, H. and Finegold SM(2011). Application of quantitative real-time PCR for rapid identification of Bacteroides fragilisgroup and related organisms in human wound samples. Anaerobe; 17(2): 64-8.
12. Lee, C.S.and Lee, J(2010). Evaluation of new gyrB-based real-time PCR system for the detection of B. fragilis as an indicator of humanspecific fecal contamination. J Microbiol Methods ; 82(3): 311-8.
13. Prindiville, T. P.; Sheikh, R. A.; Cohen, S. H.; Tang, Y. J.; Cantrell, M. C. and Silva Jr, J. (2000). Bacteroides fragilis enterotoxin gene sequences
in patients with inflammatory bowel disease. Emerging infectious diseases, 6(2): 171.
14. Merino, V. R. C.; Nakano, V., Liu C. ;Song, Y.; Finegold, S. M. and Avila-Campos, M. J. (2011). Quantitative detection of enterotoxigenic
Bacteroides fragilis subtypes isolated from children with and without diarrhea. Journal of clinical microbiology, 49(1): 416-418.
15. Ignacio, A.; Fernandes, M. R.; Avila-Campos, M. J. and Nakano, V. (2015). Enterotoxigenic and non-enterotoxigenic Bacteroides fragilis from
fecal microbiota of children. Brazilian Journal of Microbiology, 46: 1141-1145.
16. Amiri, R.; Norouzbabaei, Z.; Kalali, N.; Ghourchian, S.; Yaseri, M.; Abdollahi, A., and Douraghi, M. (2022). Identification of enterotoxigenic Bacteroides fragilis in patients with diarrhea: A study targeting 16S rRNA, gyrB and nanH genes. Anaerobe, 102546.
17. Ibrahim,N.B. and Jasim,B.J.(2022). Study the correlation between (IL-17A,IL-4)levels and some virulence genes in uropathogenic E.coli
among Iraqi wemon. Biochem. Cell. Arc, 22(1): 1381-1386.
18. Altaai, M. E.; Aziz, I. H. and Marhoon, A. A. (2014). Identification Pseudomonas aeruginosa by 16s rRNA gene for Differentiation from Other
Pseudomonas Species that isolated from Patients and environment. Baghdad Science Journal, 11(2): 1028-1034.
19. Hashim, M. H. and AlKhafaji, M. H. (2018). Isolation and identification of Citrobacter freundii from chicken meat samples using cultural and molecular techniques. Iraqi Journal of Science, 1216-1224.
20. Jasim,D.A.and Melconian,A.K(2020). Prevalence of Enterotoxigenic Bacteroides Fragilis in stool specimens collected from children less than 5 years of age in Iraq. Iraqi Journal of Science. 61(12): 3179-3186.
21. Akpınar, M.; Aktaş, E.; Cömert, F.; Külah, C. and Sümbüloğlu, V. (2010). Evaluation of the prevalence of enterotoxigenic Bacteroides fragilis
and the distribution bft gene subtypes in patients with diarrhea. Anaerobe, 16(5): 505-509.
22. Nguyen, T. V.; Le Van, P.; Le Huy, C. and Weintraub, A. 2005. Diarrhea caused by enterotoxigenic Bacteroides fragilis in children
less than 5 years of age in Hanoi, Vietnam. Anaerobe, 11(1-2): 109-114.