Related Experiment Video

Updated: Jul 21, 2025

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
07:10

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

Published on: February 19, 2019

8.9K

Genomic alterations involved in fluoroquinolone resistance development in Staphylococcus aureus

Thuc Quyen Huynh1,2,3, Van Nhi Tran1,3, Van Chi Thai1,3

  • 1School of Biotechnology, International University, Ho Chi Minh City, Vietnam.

Plos One
|July 26, 2023
PubMed
Abstract

Insights

Fluoroquinolone (FQ) resistance in Staphylococcus aureus emerges due to target mutations and increased efflux pump activity. This study investigated the mechanisms behind multidrug-resistant (MDR) S. aureus development under FQ exposure.

Area of Science:

  • Microbiology
  • Genetics
  • Pharmacology

Background:

  • Fluoroquinolones (FQ) are critical antibiotics, but their efficacy is threatened by rapidly emerging resistance.
  • Staphylococcus aureus (S. aureus) can develop multidrug resistance (MDR), posing a significant clinical challenge.

Purpose of the Study:

  • To investigate the genomic and molecular mechanisms driving the emergence of MDR S. aureus strains following exposure to fluoroquinolones.
  • To identify specific mutations and gene expression changes associated with FQ resistance in S. aureus.

Main Methods:

  • Serial sub-minimum inhibitory concentration (sub-MIC) exposure of S. aureus ATCC 29213 to ciprofloxacin, ofloxacin, or levofloxacin.
  • Whole genome sequencing (WGS) and target sequencing to identify genomic alterations.
  • RT-qPCR to quantify the expression levels of genes involved in FQ resistance, efflux pumps, and alternative sigma factors.

Main Results:

  • Significant and irreversible increases in minimum inhibitory concentrations (MICs) for FQs were observed in exposed S. aureus strains.
  • WGS revealed multiple mutations in FQ-exposed strains, including alterations in GrlA (R570H), SACOL0573, and rimI.
  • Overexpression of genes related to efflux pumps (norA, norB, norC, mgrA) and alternative sigma factors (sigB, sigS) was detected in FQ-resistant strains.

Conclusions:

  • The emergence of MDR S. aureus under FQ pressure is strongly linked to mutations within FQ target sequences.
  • Upregulation of efflux pump systems and their regulators plays a crucial role in the development of fluoroquinolone resistance in S. aureus.

More Related Videos

Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes07:44

Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes

Published on: February 14, 2025

944
Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus10:39

Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus

Published on: March 10, 2017

16.7K

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...
42
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,...
40
Antibiotic Selection00:57

Antibiotic Selection

Overview
54.8K
Genome Size and the Evolution of New Genes03:21

Genome Size and the Evolution of New Genes

While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.
8.0K
Treatment Resistant Cancers02:56

Treatment Resistant Cancers

Cancer is the second leading cause of death in the United States. A cancer cell is genetically unstable and hence can mutate faster. They can also modify their microenvironment and escape immune surveillance. The difficulties in treating cancer are further compounded by the emergence of rapid resistance to anticancer drugs. The most common ways to attain resistance in cancer cells include alteration in drug transport and metabolism, modification of drug target, elevated DNA damage response, or...
3.3K
Mutations in Microorganisms01:18

Mutations in Microorganisms

Mutations are heritable changes in an organism’s genome involving alterations in the base sequence of DNA or RNA. These changes can influence cellular processes and phenotypic traits, potentially transforming the unaltered wild type into a mutant form. Such changes, termed forward mutations, are pivotal in shaping the genetic diversity of organisms.RNA viruses exhibit the highest mutation rates due to the absence of robust proofreading mechanisms during genome replication. In contrast,...
32