Related Experiment Video

Updated: Dec 27, 2025

Visualization of Bacterial Resistance using Fluorescent Antibiotic Probes
08:23

Visualization of Bacterial Resistance using Fluorescent Antibiotic Probes

Published on: March 2, 2020

13.4K

Co-Incidence of Type II Topoisomerase Mutations and Efflux Expression in High Fluoroquinolone Resistant Enterococcus

Sarvenaz Esfahani1, Roya Ahmadrajabi1, Hamidreza Mollaei1

  • 1Department of Microbiology and Virology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.

Infection and Drug Resistance
|February 29, 2020
PubMed
Abstract

Insights

Fluoroquinolone resistance in Enterococcus faecalis urinary tract infections is common, often involving mutations in gyrA and parC. Both mutations and efflux pump gene expression likely contribute to this resistance, though other mechanisms may also be involved.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Enterococcus faecalis is a primary cause of urinary tract infections (UTIs).
  • Fluoroquinolones are common UTI treatments, but resistance is increasing.
  • Emergence of fluoroquinolone-resistant E. faecalis strains necessitates understanding resistance mechanisms.

Purpose of the Study:

  • To investigate fluoroquinolone resistance mechanisms in clinical E. faecalis UTI isolates.
  • To analyze mutations in quinolone-resistance-determining regions (QRDRs) of gyrA and parC.
  • To assess the role of EfrA, EfrB, and EmeA efflux pumps in resistance.

Main Methods:

  • Phenotypic and genotypic identification of 70 E. faecalis UTI isolates.
  • Antimicrobial susceptibility testing and minimum inhibitory concentration (MIC) determination.
  • Sequencing of gyrA and parC QRDRs and investigation of efflux pump gene expression (EfrA, EfrB, EmeA) in resistant isolates.

Main Results:

  • High-level ciprofloxacin resistance (97.5%) was prevalent in E. faecalis isolates.
  • Mutations in gyrA (65%) and parC (75%) were common.
  • Efflux genes were present in all isolates, with varying expression levels in resistant strains (EfrA 50%, EmeA 40%, EfrB 30%).
  • No significant association was found between QRDR mutations, efflux gene expression, and MIC values.

Conclusions:

  • Co-occurrence of QRDR mutations and efflux gene expression in over half of resistant isolates suggests combined roles in fluoroquinolone resistance.
  • Additional unknown mechanisms, including other efflux pumps or QRDR mutations, may contribute to fluoroquinolone resistance in E. faecalis.
Keywords:
E. faecalisUTIefflux pumpgyrAparC

More Related Videos

Recurrent Escherichia coli Urinary Tract Infection Triggered by Gardnerella vaginalis Bladder Exposure in Mice08:53

Recurrent Escherichia coli Urinary Tract Infection Triggered by Gardnerella vaginalis Bladder Exposure in Mice

Published on: December 4, 2020

6.6K
Establishment and Characterization of UTI and CAUTI in a Mouse Model08:40

Establishment and Characterization of UTI and CAUTI in a Mouse Model

Published on: June 23, 2015

20.8K

Related Concept Videos

Urinary Tract Infection II: Pathophysiology01:25

Urinary Tract Infection II: Pathophysiology

The pathophysiology of urinary tract infections (UTIs) encompasses several progressive stages, beginning with bacterial colonization and culminating in potential systemic complications if untreated. UTIs are primarily initiated by bacteria, such as Escherichia coli, which often originate from the gastrointestinal tract and migrate to the urinary system through the periurethral area. This migration can occur via several routes, including improper hygiene practices, sexual activity, or...
491
DNA Topoisomerases02:02

DNA Topoisomerases

Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. ...
34.4K
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...
1.0K