Related Experiment Video

Updated: Sep 20, 2026

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

Comparative activity of meropenem against Pseudomonas aeruginosa strains with well-characterized resistance

D M Livermore1, Y J Yang

  • 1Department of Medical Microbiology, The London Hospital Medical College, UK.

The Journal of Antimicrobial Chemotherapy
|September 1, 1989
PubMed

Insights

Meropenem shows reduced effectiveness against Pseudomonas aeruginosa with intrinsic resistance or D2-protein deficiency. However, it maintains activity against strains with most common beta-lactamases, offering a potential treatment option.

Area of Science:

  • Microbiology
  • Antimicrobial Resistance
  • Bacterial Pathogenesis

Background:

  • Pseudomonas aeruginosa is a significant opportunistic pathogen.
  • Beta-lactam antibiotics are crucial for treating P. aeruginosa infections.
  • Mechanisms of beta-lactam resistance in P. aeruginosa include cell wall impermeability, outer membrane protein loss, plasmid-mediated beta-lactamases, and chromosomal beta-lactamase hyper-production.

Purpose of the Study:

  • To evaluate the in vitro activity of meropenem against Pseudomonas aeruginosa isolates expressing known resistance mechanisms.
  • To determine if meropenem can overcome common resistance pathways in P. aeruginosa.

Main Methods:

  • In vitro testing of meropenem against P. aeruginosa isolates, mutants, and transconjugants.
  • Characterization of isolates based on four major beta-lactam resistance mechanisms.
  • Determination of meropenem minimum inhibitory concentrations (MICs).

Main Results:

  • Meropenem exhibited impaired activity against P. aeruginosa with broad-spectrum intrinsic resistance (MIC 1-2 mg/l) and D2-protein deficiency (MIC 1-2 mg/l).
  • Most common plasmid-mediated beta-lactamases (TEM, OXA, PSE) did not significantly affect meropenem MICs (0.12 mg/l).
  • Reduced susceptibility to meropenem (MIC 4 mg/l) was noted with specific uncommon beta-lactamases (NPS-1, PSE-2, OXA-3).
  • Chromosomal beta-lactamase expression did not impact meropenem MICs.

Conclusions:

  • Meropenem retains activity against P. aeruginosa strains possessing most common beta-lactam resistance mechanisms.
  • Meropenem's efficacy may be compromised by intrinsic resistance and specific uncommon beta-lactamases.
  • Meropenem demonstrates potential as a treatment option for P. aeruginosa infections, but resistance monitoring is essential.

More Related Videos

Development of a Polymicrobial Colony Biofilm Model to Test Antimicrobials in Cystic Fibrosis07:16

Development of a Polymicrobial Colony Biofilm Model to Test Antimicrobials in Cystic Fibrosis

Published on: September 20, 2024

Cystic Fibrosis Aggregate Biofilm Model to Study Infection-relevant Gene Expression08:58

Cystic Fibrosis Aggregate Biofilm Model to Study Infection-relevant Gene Expression

Published on: April 18, 2025

Related Concept Videos

Antimicrobial Effectiveness01:28

Antimicrobial Effectiveness

The effectiveness of antimicrobial agents depends on various factors influencing their ability to eliminate microbial populations. Larger microbial populations require more time for complete eradication, emphasizing the importance of population size analysis when evaluating antimicrobial efficacy.Microbial resistance to antimicrobial agents varies significantly. Highly resilient microorganisms include endospores, gram-negative bacteria, and non-enveloped viruses, while prions are exceptionally...
Gene Regulation in Microbial Communities: Quorum Sensing01:28

Gene Regulation in Microbial Communities: Quorum Sensing

Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
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...