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Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance
09:00

Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance

Published on: May 2, 2018

Characterization of imipenem-resistant Serratia marcescens producing IMP-type and TEM-type beta-lactamases encoded on

Wei-Hua Zhao1, Zhi-Qing Hu, Gelin Chen

  • 1Department of Medical Biology, Showa University School of Medicine, Tokyo, Japan. whzhao@med.showa-u.ac.jp

Microbiological Research
|August 1, 2006
PubMed

Insights

The blaIMP and blaTEM genes on a single plasmid contribute to Serratia marcescens resistance against beta-lactam antibiotics. These genes spread rapidly among Enterobacteriaceae via transmissible plasmids in clinical settings.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Serratia marcescens is an opportunistic pathogen.
  • Beta-lactam antibiotics are crucial for treating bacterial infections.
  • Antibiotic resistance, particularly to beta-lactams, is a growing global health concern.

Purpose of the Study:

  • To investigate the role of blaIMP and blaTEM genes in Serratia marcescens resistance to beta-lactams.
  • To determine the mechanisms of spread for these resistance genes.

Main Methods:

  • Analysis of 19 imipenem-resistant Serratia marcescens clinical isolates.
  • Plasmid transfer experiments (conjugation and transformation).
  • Polymerase Chain Reaction (PCR) for bla gene detection.
  • Pulsed-field gel electrophoresis (PFGE) for genomic analysis.

Main Results:

  • Six isolates harbored both blaIMP and blaTEM genes on a single, transferable plasmid.
  • Transconjugants and transformants exhibited high-level resistance to ampicillin, cephalexin, cefoxitin, and cefotaxime.
  • Reduced susceptibility to imipenem was observed, while aztreonam susceptibility was maintained.
  • blaIMP and blaTEM gene expression was constitutive in all tested strains.

Conclusions:

  • The blaIMP and blaTEM genes, located on a single plasmid, confer significant beta-lactam resistance in Serratia marcescens.
  • The presence of these genes on transferable plasmids facilitates their rapid dissemination within clinical environments.
  • Understanding these resistance mechanisms is vital for controlling the spread of antibiotic resistance in Enterobacteriaceae.

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