Quantitative Detection of Enterotoxigenic
            <i>Bacteroides fragilis</i>
            Subtypes Isolated from Children with and without Diarrhea

Merino, Victor Rafael Castillo; Nakano, Viviane; Liu, C.; Song, Yuanyuan; Finegold, Sydney M.; Avila-Campos, Mario Júlio

doi:10.1128/jcm.01556-10

Cited by 32 publications

(25 citation statements)

References 15 publications

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“…Although the incidence of CRC was reported lower in Iran compared to other countries, its rate was anticipated to increase in the future (Hosseini et al, 2004;Malekzadeh et al, 2009). In previous studies, it was also reported that ETBF may have a role in diarrhea and IBD (Myers et al, 1987;Prindiville et al, 2000;Basset et al, 2004;Merino et al, 2011;Purcell et al, 2017;Zamani et al, 2017). Some investigations have suggested that certain bacterial species (e.g., ETBF) may operate as pathogenic bacteria that clarify the development of dysbiosis in microbial community of the gut and trigger CRC (Hajishengallis et al, 2012;Hajishengallis and Lamont, 2016).…”

Section: Discussionmentioning

confidence: 96%

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Enterotoxigenic Bacteroides fragilis: A Possible Etiological Candidate for Bacterially-Induced Colorectal Precancerous and Cancerous Lesions

Zamani

Taslimi

Sarabi

et al. 2020

Front. Cell. Infect. Microbiol.

100

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Enterotoxigenic Bacteroides fragilis (ETBF) produces Bacteroides fragilis toxin (BFT), which is associated with acute diarrheal, inflammatory bowel disease, and colorectal cancer (CRC). In experimental models, ETBF has been shown to contribute to colon carcinogenesis. The present study was conducted to investigate mucosal colonization of ETBF in the colon to find a possible association between the presence of ETBF and precancerous and cancerous lesions. The mucosal biopsies of involved sites were obtained from 68 patients with precancerous and cancerous lesions and 52 healthy controls (HC). The samples were cultured on Bacteroides Bile Esculin agar. Then, specific primers were designed to detect B. fragilis and bft gene using quantitative real-time PCR, and the possible links of ETBF with clinicopathological characteristics was evaluated. Also real-time PCR was performed to detect the bft gene subtypes. Bacteroides fragilis was detected in 51% of the patients and 48% of HCs cultures. The 16SrRNA gene was found to be present in 63 and 81% of the patients and HCs' samples, respectively. Moreover, the bft gene was detected in 47 and 3.8% of the patients and HCs, respectively. Also, B. fragilis was significantly more abundant in the patients' samples compared to those of HCs. In the patient group, higher odds ratio (OR) of ETBF was significantly associated with serrated lesions and adenoma with low-grade dysplasia. The bft1 gene was the most prevalent subtype of bft gene, followed by the bft2 gene. This was the first study in Iran to demonstrate increased positivity of ETBF in patients with precancerous and cancerous lesions. In this study, the bft gene was found to be associated with CRC, especially in the patients with precancerous lesions and initial carcinogenic lesions. Moreover, the results suggest that mucosal BFT exposure is common and could be a risk factor and a screening marker for developing CRC.

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Section: Discussionmentioning

confidence: 96%

“…All the primers and probes used for the detection of all bft gene types had been designed in our previous study (Zamani et al, 2017). In order to detect the bft gene subtypes, the real-time PCR was performed as previously described (Merino et al, 2011).…”

Section: Real-time Pcrmentioning

confidence: 99%

Enterotoxigenic Bacteroides fragilis: A Possible Etiological Candidate for Bacterially-Induced Colorectal Precancerous and Cancerous Lesions

Zamani

Taslimi

Sarabi

et al. 2020

Front. Cell. Infect. Microbiol.

100

View full text Add to dashboard Cite

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“…B. fragilis represents a common cause of endogenous infections in humans that is frequently associated with polymicrobial infections such as intra-abdominal, diabetic foot, obstetric-gynecologic tract and surgical site infections, as well as toxin-dependent diarrhea in adults and children (7, 8). Enterotoxigenic Bacteroides fragilis (ETBF) induced diarrhea in children has been reported by different researchers in various parts of the world, but ETBF has also been found in non-diarrheal fecal samples (9, 10). …”

Section: Introductionmentioning

confidence: 99%

Role of Enterotoxigenic Bacteroides fragilis in Children Less Than 5 Years of Age With Diarrhea in Tabriz, Iran

Akhi

Seifi

Asgharzadeh

et al. 2016

Jundishapur J Microbiol

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BackgroundDiarrhea is the most frequent health problem among children in developing countries. Defining the etiology of acute diarrhea is critical to disease therapy and prevention. Some anaerobic bacteria such as Enterotoxigenic Bacteroides fragilis (ETBF) strains cause diarrheal disease by production of enterotoxin in children less than 5 years old.ObjectivesThis study aimed to evaluate the prevalence of ETBF among common bacteria and viruses causing diarrhea in children aged less than five years.Materials and MethodsOne hundred diarrheal stools were cultured for detection of aerobic and anaerobic pathogen bacteria by direct plating on selective media and antibiotic susceptibility tests were performed according to clinical and laboratory standards institute (CLSI) guidelines on isolates of ETBF. The enterotoxigenic gene among B. fragilis isolates was also investigated using the polymerase chain reaction (PCR) method. Detection of viral pathogens was carried out using the latex agglutination test.ResultsTen B. fragilis were isolated from 100 diarrheal fecal specimens. All isolates were susceptible to metronidazole, while 10% were susceptible to clindamycin. Four (40%) ETBF were isolated. Rotaviruses (57.2%) and adenoviruses (18.6%) were the most frequently detected etiological agents.ConclusionsETBF is one of the etiological agents that may cause diarrhea in children but it is not the commonest of them. Metronidazole is still an effective antibiotic against B. fragilis. Viruses are the most important etiological agents of diarrhea in children less than 5 years of age.

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“…In that respect, molecular assays, given their fast turnaround times and high sensitivities, could facilitate a better diagnostic procedure. Studies on PCR-based detection of B. fragilis have focused on enterotoxigenic strains in fecal specimens (4)(5)(6)(7) or as an indicator of water contamination (8)(9)(10). In contrast, detection of B. fragilis in general clinical practice, using either conventional PCR (C-PCR) (11,12) or real-time PCR (RT-PCR) (13), is limited.…”

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confidence: 99%

Comparative Evaluation of Conventional and Real-Time PCR Assays for Detecting Bacteroides fragilis in Clinical Samples

et al. 2013

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cA conventional PCR and a real-time PCR for detecting Bacteroides fragilis were evaluated against clinical specimens. Analytical sensitivities were 100 and 40 fg of DNA, respectively. Detection limits were 100 and 10 CFU/ml, respectively. A total of six culture-negative specimens were positive by PCR. Altering the gold standard from "positive culture" to "positive culture or both PCR assays positive" resulted in sensitivities of 91.7% and 100%, respectively, and in specificities of 100% and 98.6%, respectively.

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Quantitative Detection of Enterotoxigenic Bacteroides fragilis Subtypes Isolated from Children with and without Diarrhea

Cited by 32 publications

References 15 publications

Enterotoxigenic Bacteroides fragilis: A Possible Etiological Candidate for Bacterially-Induced Colorectal Precancerous and Cancerous Lesions

Enterotoxigenic Bacteroides fragilis: A Possible Etiological Candidate for Bacterially-Induced Colorectal Precancerous and Cancerous Lesions

Role of Enterotoxigenic Bacteroides fragilis in Children Less Than 5 Years of Age With Diarrhea in Tabriz, Iran

Comparative Evaluation of Conventional and Real-Time PCR Assays for Detecting Bacteroides fragilis in Clinical Samples

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