Related Experiment Video
Updated: May 3, 2026
08:58
Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
8.8K
[Fluoroquinolone resistance determining region mutation in Streptococcus pneumonia isolates]
Fei-fei Zhang1, Chun-jiang Zhao1, Hui Wang1
1Department of Clinical Laboratory, Peking University People's Hospital,Beijing 100044, China.
Summary
Fluoroquinolone resistance in Streptococcus pneumoniae is linked to specific gene mutations. Single mutations in parE/parC cause low-level resistance, while double mutations in parC/parE and gyrA are associated with moxifloxacin resistance.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Context:
- Streptococcus pneumoniae is a significant human pathogen.
- Fluoroquinolones are critical antibiotics for treating pneumococcal infections.
- Understanding antimicrobial resistance mechanisms is crucial for effective treatment strategies.
Purpose:
- To investigate the genotypic basis of fluoroquinolone resistance in Streptococcus pneumoniae.
- To correlate specific mutations in target genes (parC, parE, gyrA) with varying levels of resistance to ciprofloxacin, levofloxacin, and moxifloxacin.
Summary:
- This study analyzed 232 Streptococcus pneumoniae isolates for fluoroquinolone resistance.
- Mutations in the quinolone resistance-determining regions (QRDR) of parC, parE, and gyrA genes were identified using PCR and sequencing.
- Single mutations in parE/parC correlated with low-level resistance to levofloxacin and ciprofloxacin, whereas double mutations in parC/parE and gyrA were linked to moxifloxacin resistance.
Impact:
- Provides insights into the molecular mechanisms of fluoroquinolone resistance in Streptococcus pneumoniae.
- Informs clinical decision-making for antibiotic selection in treating pneumococcal infections.
- Contributes to antimicrobial stewardship efforts by highlighting the genetic underpinnings of resistance.
Related Concept Videos
01:25Mechanism of Antibiotic Resistance in MRSA
219
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...
219
01:28Inhibitors of Bacterial DNA Synthesis
130
Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These...
130
01:25Clinical Significance of Antibiotic Resistance
90
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...
90
01:30Development of Antibiotic Resistance
2.0K
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...
2.0K
01:28Gene Regulation in Microbial Communities: Quorum Sensing
954
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,...
954