Antimicrobial resistance from enterococci in a pediatric hospital. Plasmids in Enterococcus faecalis isolates with

Related Experiment Video

Updated: Aug 19, 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

G Miranda1, L Lee, C Kelly

  • 1Unidad de Investigación en Epidemiología Hospitalaria, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social (IMSS), Mexico City, Mexico. guadalumiranda@infosel.net.mx

Archives of Medical Research
|May 10, 2001
PubMed

Insights

Antimicrobial resistance in Enterococcus spp. is common in pediatric hospitals. High-level gentamicin resistance (HLGR) is infrequent and appears to spread via a single plasmid.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Clinical Research

Background:

  • Enterococcus spp. are significant nosocomial and community-acquired pathogens.
  • Increasing importance of Enterococcus spp. in pediatric infections, especially in hospital settings.
  • Study focuses on antimicrobial resistance patterns and high-level gentamicin resistance (HLGR) plasmids in Enterococcus faecalis.

Purpose of the Study:

  • To determine the frequency of antimicrobial resistance in enterococci.
  • To characterize high-level gentamicin resistance (HLGR) plasmids in Enterococcus faecalis clinical isolates.
  • To investigate the prevalence and characteristics of HLGR in a pediatric hospital setting.

Main Methods:

  • Collected 289 enterococcal isolates from a tertiary-care pediatric hospital over 18 months.
  • Screened isolates for antibiotic resistance, including HLGR.
  • Utilized pulsed-field electrophoresis (PFGE) typing, plasmid analysis, and filter matings to assess resistance transferability.

Main Results:

  • Enterococcus faecalis comprised 76% of isolates; other species included E. avium, E. faecium, and E. casseliflavus.
  • Antimicrobial resistance rates: ampicillin/penicillin 29%, imipenem 17%, vancomycin 3%, and HLGR 5%.
  • Fifteen HLGR isolates identified; five E. faecalis strains showed transferable gentamicin and streptomycin resistance via a homogeneous 47 kb plasmid.

Conclusions:

  • Antimicrobial resistance in Enterococcus spp. is prevalent in this pediatric hospital.
  • The frequency of high-level gentamicin-resistant strains is relatively low.
  • Dissemination of HLGR appears to be mediated by a single, transferable plasmid.
Abstract

More Related Videos

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

Detection of Horizontal Gene Transfer Mediated by Natural Conjugative Plasmids in E. coli06:56

Detection of Horizontal Gene Transfer Mediated by Natural Conjugative Plasmids in E. coli

Published on: March 24, 2023

Related Concept Videos

Antibiotic Selection00:57

Antibiotic Selection

Overview
Determination of Multiple Dosing Parameters: Steady-State, Minimum and Maximum Concentrations01:15

Determination of Multiple Dosing Parameters: Steady-State, Minimum and Maximum Concentrations

Gentamicin, an aminoglycoside antibiotic, is commonly administered via intermittent intravenous infusion to treat severe infections. An intermittent one-hour infusion of gentamicin, administered at eight-hour intervals, allows for precise control of plasma drug concentrations, minimizing toxicity while ensuring therapeutic efficacy. Pharmacokinetic principles govern the dynamics of plasma concentrations and can be mathematically described using specific equations.The plasma drug concentration...
Plasmids01:28

Plasmids

Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...
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...