Antimicrobial resistance in the Bacteroides fragilis group in faecal microbiota from healthy Danish children

- Faecal Bacteroides fragilis group isolates from healthy children were characterised.
- The rate of reduced susceptibility to meropenem was 1.9% and clindamycin 21.2%.
- The rate of reduced susceptibility to piperacillin/tazobactam was 5.0%.
- No metronidazole-resistant isolates were found.

The Bacteroides fragilis group constitute a significant portion of the human gut microbiota and comprise a major proportion of anaerobic bacteria isolated in human infections. We established a baseline of antimicrobial susceptibility rates in the B. fragilis group in the intestinal tract of relatively antibiotic-naive healthy Danish children. From 174 faecal samples collected from children attending day care, 359 non-duplicate isolates were screened for antimicrobial susceptibility. Of these, 0.0%, 1.9%, 5.0% and 21.2% of isolates were intermediate-susceptible or resistant to metronidazole, meropenem, piperacillin/tazobactam and clindamycin, respectively. Eighteen additional studies reporting susceptibility rates in the B. fragilis group bacteria were identified by conducting a literature search. Heterogeneity among results from studies of B. fragilis group antimicrobial susceptibility rates in faecal microbiota exists.