Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of
individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such
as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated
the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of
children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal
samples from children aged 0–5 years old were evaluated. BFG strains were isolated and identified by
conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and
enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug
susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated
bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic), and
4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin,
ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol.
The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The
molecular methodology was more effective in identifying the B. fragilis group when compared to the
biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts
about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed
to gain a better understanding of the role of these bacteria in acute diarrhea in children.
