Related Experiment Video

Updated: Sep 26, 2026

Characterizing Multidrug Efflux Systems in Acinetobacter baumannii Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System
05:06

Characterizing Multidrug Efflux Systems in Acinetobacter baumannii Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System

Published on: January 5, 2024

Modification of outer membrane protein profile and evidence suggesting an active drug pump in Enterobacter aerogenes

Stéphane Gayet1, Renaud Chollet, Gérard Molle

  • 1EA2197-IFR 48, Faculté de Médecine, 13385 Marseille Cedex 05. UMR 5048, CNRS, U554 INSERM, 34090 Montpellier, France.

Antimicrobial Agents and Chemotherapy
|April 24, 2003
PubMed

Insights

Multidrug-resistant Enterobacter aerogenes strains exhibit altered outer membrane proteins and O-polysaccharide, suggesting stress-induced resistance mechanisms similar to Escherichia coli.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Drug Resistance

Background:

  • Enterobacter aerogenes is a clinically significant pathogen.
  • Multidrug resistance (MDR) in bacteria poses a major public health threat.
  • Understanding resistance mechanisms is crucial for developing effective treatments.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying multidrug resistance in two clinical isolates of Enterobacter aerogenes.
  • To characterize the outer membrane protein profiles and O-polysaccharide structures of resistant strains.
  • To explore potential efflux pump involvement in chloramphenicol resistance.

Main Methods:

  • Phenotypic analysis of antibiotic resistance.
  • Outer membrane protein profiling using SDS-PAGE.
  • O-polysaccharide characterization.
  • Analysis of intracellular drug accumulation in the presence of carbonyl cyanide m-chlorophenylhydrazone.

Main Results:

  • Both resistant strains displayed a reduced major porin and overproduced OmpX and LamB outer membrane proteins.
  • A semirough Ra O-polysaccharide phenotype was observed, replacing the full-length O-polysaccharide.
  • One isolate showed increased intracellular chloramphenicol accumulation with an uncoupler, indicating energy-dependent efflux.
  • Resistance strategies resembled those induced by stress in Escherichia coli.

Conclusions:

  • Alterations in outer membrane porins and O-polysaccharide contribute to multidrug resistance in Enterobacter aerogenes.
  • Energy-dependent efflux may play a role in chloramphenicol resistance.
  • The observed resistance mechanisms are analogous to stress responses in Escherichia coli, highlighting conserved bacterial defense strategies.

More Related Videos

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa13:40

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

Published on: February 17, 2014

Related Concept Videos

Development of Antibiotic Resistance01:30

Development of Antibiotic Resistance

Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...
Antibiotic Selection01:45

Antibiotic Selection

Researchers use antibiotic resistance genes to identify bacteria that possess a plasmid containing their gene of interest. Antibiotic resistance naturally occurs when a spontaneous DNA mutation creates changes in bacterial genes that eliminate antibiotic activity. Bacteria can share these new resistance genes with their offspring and other bacteria. The overuse and misuse of antibiotics have created a public health crisis, as resistant and multi-resistant bacteria continue to develop.Antibiotic...