Antimicrobial resistance and prevalence of resistance genes in intestinal Bacteroidales strains

Clinics (Sao Paulo). 2011;66(4):543-7. doi: 10.1590/s1807-59322011000400004.


Objective: This study examined the antimicrobial resistance profile and the prevalence of resistance genes in Bacteroides spp. and Parabacteroides distasonis strains isolated from children's intestinal microbiota.

Methods: The susceptibility of these bacteria to 10 antimicrobials was determined using an agar dilution method. β-lactamase activity was assessed by hydrolysis of the chromogenic cephalosporin of 114 Bacteriodales strains isolated from the fecal samples of 39 children, and the presence of resistance genes was tested using a PCR assay.

Results: All strains were susceptible to imipenem and metronidazole. The following resistance rates were observed: amoxicillin (93%), amoxicillin/clavulanic acid (47.3%), ampicillin (96.4%), cephalexin (99%), cefoxitin (23%), penicillin (99%), clindamycin (34.2%) and tetracycline (53.5%). P-lactamase production was verified in 92% of the evaluated strains. The presence of the cfiA, cepA, ermF, tetQ and nim genes was observed in 62.3%, 76.3%, 27%, 79.8% and 7.8% of the strains, respectively.

Conclusions: Our results indicate an increase in the resistance to several antibiotics in intestinal Bacteroides spp. and Parabacteroides distasonis and demonstrate that these microorganisms harbor antimicrobial resistance genes that may be transferred to other susceptible intestinal strains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Anti-Bacterial Agents / pharmacology*
  • Bacteroides / drug effects*
  • Bacteroides / genetics
  • Bacteroides / isolation & purification
  • Child
  • Drug Resistance, Bacterial / drug effects
  • Drug Resistance, Bacterial / genetics*
  • Genes, Bacterial / drug effects
  • Genes, Bacterial / genetics
  • Humans
  • Imipenem / pharmacology
  • Intestines / microbiology*
  • Metronidazole / pharmacology
  • Microbial Sensitivity Tests


  • Anti-Bacterial Agents
  • Metronidazole
  • Imipenem