Conjugal transfer of imipenem resistance in Bacteroides fragilis

J Antibiot (Tokyo). 1992 Apr;45(4):542-7. doi: 10.7164/antibiotics.45.542.


Transfer of imipenem resistance in Bacteroides fragilis was studied. Clinical isolate B. fragilis 10-73 was highly resistant to imipenem. Imipenem resistance was transferred from 10-73 to B. fragilis strain TM4000 at a frequency of 10(-6)/input recipient by a filter mating technique. The resistance could also be retransferred. B. fragilis 10-73 and both primary and secondary transcipients produced an imipenem-hydrolyzing metallo-beta-lactamase. Acquisition of imipenem resistance correlated with the appearance of plasmid DNA with a size (ca. 13.6 kb) similar to that of the donor strain. TM4000 transformed by electroporation with purified DNA of the 13.6-kb plasmid pBFUK1 produced the metallo-beta-lactamase and was resistant to imipenem. Transfer was resistant to DNase treatment and no transfer was seen with a sterile filtrate of the donor culture. It is suggested that gene transfer in B. fragilis has the properties of a conjugation system rather than those of transformation or transduction.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Bacteroides fragilis / drug effects
  • Bacteroides fragilis / enzymology
  • Bacteroides fragilis / genetics*
  • Conjugation, Genetic / drug effects*
  • DNA, Bacterial / genetics
  • Drug Resistance, Microbial
  • Electrophoresis, Agar Gel
  • Imipenem / pharmacology*
  • Microbial Sensitivity Tests
  • Phenotype
  • Plasmids / genetics
  • Transfection*
  • beta-Lactamases / metabolism


  • Anti-Bacterial Agents
  • DNA, Bacterial
  • Imipenem
  • beta-Lactamases