Related Experiment Video

Updated: Aug 17, 2026

A Protocol for Functional Assessment of Whole-Protein Saturation Mutagenesis Libraries Utilizing High-Throughput Sequencing
11:36

A Protocol for Functional Assessment of Whole-Protein Saturation Mutagenesis Libraries Utilizing High-Throughput Sequencing

Published on: July 3, 2016

Penicillin-binding protein 5 sequence alterations in clinical isolates of Enterococcus faecium with different levels

T Rybkine1, J L Mainardi, W Sougakoff

  • 1L.R.M.A. UFR Broussais-Hôtel-Dieu et UFR Pitié-Salpétrière, Université Paris VI, France.

The Journal of Infectious Diseases
|July 4, 1998
PubMed

Insights

Penicillin-binding protein 5 (PBP 5) mutations drive beta-lactam antibiotic resistance in Enterococcus faecium. Specific amino acid changes in PBP 5 correlate with high-level resistance, impacting treatment options.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Antibiotic Resistance

Background:

  • Penicillin-binding protein (PBP) 5 is a primary target for beta-lactam antibiotics in Enterococcus faecium.
  • PBP 5 plays a crucial role in mediating resistance to beta-lactam antibiotics within this bacterial species.

Purpose of the Study:

  • To analyze PBP 5 variants in clinical Enterococcus faecium isolates with varying beta-lactam resistance levels.
  • To identify specific amino acid substitutions in PBP 5 associated with high-level beta-lactam resistance.

Main Methods:

  • Analysis of PBP 5 variants from 15 clinical Enterococcus faecium isolates.
  • Correlation of specific amino acid substitutions with observed minimum inhibitory concentrations (MICs) for beta-lactam antibiotics.

Main Results:

  • Highly beta-lactam-resistant isolates predominantly produced low-affinity PBP 5 in small quantities.
  • Key amino acid substitutions identified include Ala/Ile for Thr-499, Glu for Val-629, and Pro for Ser-667.
  • Specific mutations near the SDN box (Met-485 to Thr/Ala) and insertions near Ser-466 were linked to high ampicillin MICs (up to 256 µg/mL).

Conclusions:

  • Specific point mutations and their combinations within PBP 5 are key determinants of high-level beta-lactam resistance in Enterococcus faecium.
  • Understanding these mutations can inform strategies to combat antibiotic resistance in E. faecium infections.

More Related Videos

Generating Transposon Insertion Libraries in Gram-Negative Bacteria for High-Throughput Sequencing08:19

Generating Transposon Insertion Libraries in Gram-Negative Bacteria for High-Throughput Sequencing

Published on: July 7, 2020

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes08:58

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

Published on: March 3, 2023

Related Concept Videos

Antibiotic Selection00:57

Antibiotic Selection

Overview
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...
Production of Antibiotics01:27

Production of Antibiotics

Penicillin, one of the earliest and most widely used antibiotics, is produced industrially by the filamentous fungus Penicillium chrysogenum. Large stirred-tank bioreactors ranging from tens to hundreds of thousands of liters maintain tightly controlled temperature, pH, and dissolved oxygen conditions to support fungal metabolism and maximize antibiotic yield. Penicillin is a secondary metabolite, synthesized primarily during the stationary growth phase, which requires a carefully managed...
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...
Inhibitors of Gram-positive Cell Wall Synthesis01:23

Inhibitors of Gram-positive Cell Wall Synthesis

Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
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...