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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

WITHDRAWN: [Clinical strain of Proteus mirabilis able to produce a plasmid mediated ceftazidimase.]

N Ben Achour1, C Chouchani, N Bouhawela

  • 1Laboratoire de biochimie et de biotechnologie, faculté des sciences de Tunis, campus universitaire, 2092 EL-Manar-II, Tunisie.

Pathologie-Biologie
|June 19, 2007
PubMed

Insights

Extended spectrum beta-lactamases (ESBLs) in Proteus mirabilis confer multidrug resistance. A specific ESBL, encoded by the pNC4150 plasmid, was identified as responsible for resistance to key antibiotics.

Area of Science:

  • Microbiology
  • Biochemistry
  • Molecular Biology

Background:

  • Extended spectrum beta-lactamases (ESBLs) are a significant challenge in managing Gram-negative bacterial infections.
  • ESBL-producing bacteria contribute to multidrug resistance, complicating treatment options worldwide.

Purpose of the Study:

  • To investigate the enzymatic mechanism and properties of ESBLs from a clinical Proteus mirabilis strain.
  • To characterize the ESBL enzymes responsible for resistance in a Tunisian intensive care unit isolate.

Main Methods:

  • Identification and antimicrobial susceptibility testing of Proteus mirabilis NC4150.
  • Analysis of beta-lactamase activity, isoelectric points, and inhibition by clavulanic acid and sulbactam.
  • Plasmid analysis and gene transfer experiments (transformation and conjugation) to identify the ESBL gene carrier.

Main Results:

  • Two beta-lactamases with isoelectric points of 5.4 and 5.7 were identified, conferring resistance to oxyimino beta-lactams.
  • The beta-lactamase with pI 5.7 specifically hydrolyzed ceftazidime and was inhibited by clavulanic acid and sulbactam.
  • The gene for the ESBL with pI 5.7 was located on a transferable plasmid, pNC4150.

Conclusions:

  • The study identified a novel ESBL enzyme in Proteus mirabilis responsible for resistance to third-generation cephalosporins.
  • The findings highlight the role of transferable plasmids in the dissemination of ESBL-producing bacteria in clinical settings.
  • Understanding these mechanisms is crucial for effective infection control and antimicrobial stewardship.

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