Prevalence and antimicrobial susceptibility of enterotoxigenic Bacteroides fragilis in children with diarrhoea in Nicaragua

Enterotoxigenic Bacteroides fragilis (ETBF) strains have been reported as a cause of diarrhoeal diseases. Diarrhoea is an important cause of morbidity and mortality in children from developing countries. This study was conducted to determine the prevalence and antimicrobial susceptibility of ETBF in children from Leon, Nicaragua. Faecal specimens from 106 children under ten years of age with diarrhoea and 60 asymptomatic, age-matched controls were examined for presence of ETBF using an assay based on immunomagnetic separation (IMS) in combination with PCR (IMS-PCR) and HT29/C1 cell assay. ETBF was present in nine children with diarrhoea (8.4%) and was more often identified in children less than or equal to 1 year (7/63, 11.1%) but all ETBF positive children were under 2 years of age. ETBF was isolated as the only pathogen in five of nine positive children (55.5%). The agar dilution method was used to determine the antimicrobial susceptibility pattern of the ETBF strains. All strains were resistant to ampicillin (range 8-1024 mg/L) and one strain was also resistant to clindamycin MIC 256 mg/L. All the other antimicrobial agents were active against the strains (MIC50 and MIC90): 8 and 16 mg/L for cefoxitin, 0.004 and 0.008 mg/L for imipenem, 0.5 and 0.5 mg/L for clindamycin and for metronidazole, 2 and 4 mg/L for chloramphenicol. A majority (77%) of the ETBF strains were beta-lactamase producers. (C) 2000 Academic Press.