Clinical medicinePrevalence of Enterotoxigenic Bacteroides fragilis in patients with diarrhea: A controlled study
Introduction
Diarrhea is the second important cause of deaths in the worldwide. Although developed microbiologic methods have been used, the etiology cannot be explained in about half of diarrheal cases [1]. The involvement of Bacteroides fragilis which produces an enterotoxin (fragylisin) in the etiology of diarrheal diseases has been the subject of some investigations for last 25 years. These studies suggest that Enterotoxigenic Bacteroides fragilis (ETBF) may play possible role in diarrheal diseases in different populations [2], [3], [4], [5]. In contrast to these, according to some other reports non-diarrheic humans can be the carrier of ETBF [6], [7], [8].
Detection of ETBF from stool specimens is based on culturing on selective media and analysis of the specimens for the presence of B. fragilis enterotoxin by cytotoxicity assay in HT-29 cell cultures and polymerase chain reaction (PCR) methods [9]. Culture systems require time and their sensitivity can be affected by the storage condition of the specimens prior to culturing. Although the HT29/C1 cell assay is very sensitive detecting as picomolar level of B. fragilis toxin, PCR methods may well be more sensitive for diagnosis [7], [10], [11]. This study was performed to detect the prevalence of ETBF in stool specimens from children and adults with and without diarrhea by nested PCR method.
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Patients
The patients with diarrhea who were admitted to the University Hospital and Government Hospital between 19 December 2003 and 16 August 2004 were studied prospectively. These hospitals serve a population of about 850 000 in Malatya, which is a city in east of Turkey. During the period there was no outbreak of diarrhea in this area. All of the patients were outpatients with acute watery diarrhea. Stool specimens were obtained from 104 adults (aged >16 years) and 117 children (aged 0–16 years).
Controls
Results
B. fragilis gene was detected in 22 (10.0%) of the 221 patients and in 23 (11, 7%) of the 197 controls. In totally, there was no significant difference on ETBF positivity between two groups. When the age groups were considered, we found that the prevalence of ETBF was slightly higher in children with diarrhea (11.1%) than in control children (7.8%) (). Distribution of ETBF positivitiy according to age group of the patients and controls was shown in Table 1. The rate of ETBF in the
Discussion
Detection rate of ETBF in stool specimens depends on amount of toxin produced, sensitivity of the assay, and stability of the toxin which is susceptible to degradation by proteases [12]. Nested PCR used in this study is rapid, sensitive, specific and useful assay for diagnosis of ETBF in diarrheal diseases. This method can detect as little as 1 pg of enterotoxigenic DNA or 100–1000 cells of ETBF per g of stool [9], [13].
Living conditions in developing countries and different geographic areas may
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Cited by (22)
Identification of enterotoxigenic Bacteroides fragilis in patients with diarrhea: A study targeting 16S rRNA, gyrB and nanH genes
2022, AnaerobeCitation Excerpt :In addition, bft-1 is identified as the most prevalent subtypes of bft in patients with diarrhea [18–20]. Due to the small number of ETBF tested in this study, we could not reach a clear conclusion about the distribution of bft subtypes in children and adults as demonstrated previously by others [21,22]. Another finding of this study is that the majority of B. fragilis isolates obtained from patients with diarrhea did not harbor the bft gene.
Good Gone Bad: One Toxin Away From Disease for Bacteroides fragilis
2020, Journal of Molecular BiologyCitation Excerpt :Reports from distinct urban and underdeveloped geographic locations show higher percentages of ETBF colonization in children older than 1 year with diarrhea than in age-matched controls [25,28–32]. Interestingly, in children younger than 1 year, prevalence is the lowest in the general population and is not associated with diarrhea, suggesting that the developmental trajectory is important for diarrheal association to occur [28,32]. An association of ETBF with chronic intestinal disease has been established for more than 20 years, the first reported in patients with inflammatory bowel disease (IBD) [33].
Evaluation of the prevalence of enterotoxigenic Bacteroides fragilis and the distribution bft gene subtypes in patients with diarrhea
2010, AnaerobeCitation Excerpt :Pantosti et al. reported, by anaerobe culture method, high rates of ETBF in healthy individuals from Italy [19]. In a study from Turkey, 22 (9.9%) out of 221 patients and 23 (11.6%)out of 197 controls had bft gene shown by nested polymerase PCR [6]. In our study, the presence of bft gene was detected in 29 (15%) of patients and 27 (14%) of control group.
Emerging infections of the gastrointestinal tract
2009, Best Practice and Research: Clinical GastroenterologyAdvances in defining etiology and new therapeutic approaches in acute diarrhea
2007, Journal of InfectionCitation Excerpt :ETBF has been associated with acute diarrhea in children ≤5 years of age.6–8 The important reservoir for human infection by ETBF may be infected persons6 or animals.7 In a mouse model, strains harboring bft-1 or bft-2 gene subtypes have been shown to cause significant histopathological alterations of the intestine.9