Detection of Enterotoxigenic Bacteroides fragilis by Polymerase Chain Reaction

Background: Enterotoxigenic Bacteroides fragilis (ETBF) has received much attention as an emerging enteropathogen causing diarrhea in animals, children and adults, but no such studies have been reported in China. Aims: To investigate the positivity rate of ETBF in various populations by polymerase chain reaction (PCR) assay of ETBF. Methods: PCR detection assay of ETBF was established, and its sensitivity and specificity were evaluated. PCR was used to detect the positivity rate of ETBF directly in normal control group and diarrhea group. Results: The sensitivity of PCR detection was found to be 1×104 CFU/ml, and the PCR assay for normal intestinal bacteria and pathogenic bacteria were negative. The positivity rates of ETBF in normal control group and diarreha group were 3.6% and 6.4%(P=0.042), respectively, these were 2.3% in adult control group and 5.7% in adult diarrhea group (P=0.047), respectively, while 5.1% in children control group and 7.3% in children diarrhea group (P=0.33), respectively. Conclusions: PCR is a sensitive and specific assay for detection of ETBF in fecal samples. ETBF might be one of the etiological pathogens of diarrhea.