Related Experiment Video
Updated: Feb 21, 2026
08:19
Generating Transposon Insertion Libraries in Gram-Negative Bacteria for High-Throughput Sequencing
Published on: July 7, 2020
11.5K
Cryptic silver resistance is prevalent and readily activated in certain Gram-negative pathogens
Elham Elkrewi1, Christopher P Randall1, Nicola Ooi1
1Antimicrobial Research Centre and School of Molecular and Cellular Biology, University of Leeds, Leeds LS29JT, UK.
The Journal of Antimicrobial Chemotherapy
|October 6, 2017
Summary
Cryptic silver (Ag+) resistance is common in Enterobacter and Klebsiella, readily activated by mutations. Overt Ag+ resistance is rare in Gram-negative pathogens, but the sil operon enables its emergence.
Area of Science:
- Microbiology
- Genetics
- Antimicrobial Resistance
Background:
- Silver (Ag+) resistance is a growing concern in clinical settings.
- Understanding the mechanisms of Ag+ resistance is crucial for combating bacterial infections.
Purpose of the Study:
- To determine the prevalence of cryptic Ag+ resistance in Gram-negative bacteria.
- To investigate the activation of overt Ag+ resistance in clinical isolates.
Main Methods:
- Susceptibility testing of 444 clinical isolates to Ag+.
- Assessing the emergence of Ag+ resistance via spontaneous mutation.
- Investigating the genetic basis of Ag+ resistance using PCR and DNA sequencing.
Main Results:
- No overt Ag+ resistance was observed initially.
- High-level Ag+ resistance was selected in 76% of Enterobacter spp., 58% of Klebsiella spp., and 0.7% of E. coli.
- Resistance was linked to the sil operon, activated by mutations in silS, and absent in strains lacking sil.
Conclusions:
- Cryptic Ag+ resistance via the sil operon is prevalent in Enterobacter and Klebsiella.
- This resistance is easily activated by mutations.
- Overt Ag+ resistance is uncommon but can emerge through specific genetic mechanisms.
More Related Videos
Related Concept Videos
01:30Development of Antibiotic Resistance
1.6K
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...
1.6K
01:28Gene Regulation in Microbial Communities: Quorum Sensing
750
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,...
750
01:23Stringent Response in E. coli
411
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
411
01:31Defense Against Bacterial Pathogens
3.0K
The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
3.0K
01:30Bacterial Phylum Actinobacteria
712
Coryneform bacteria are gram-positive, aerobic, nonmotile rods that exhibit irregular, club-shaped, or V-shaped arrangements. Their V-shape results from snapping division, where the inner cell wall layer forms the cross-wall, while the outer layer remains intact until it ruptures on one side, causing the daughter cells to bend away.The primary genera are Corynebacterium and Arthrobacter. Corynebacterium includes diverse species, ranging from saprophytes to pathogens like Corynebacterium...
712
01:17Gram-negative Bacterial Protein Secretion Systems
1.1K
Gram-negative bacteria utilize sophisticated protein secretion systems to transport proteins across their double-membrane envelope into the extracellular environment or host cells. Based on their mechanism of action, these systems are classified into one-step and two-step pathways.One-Step Secretion Systems (Types I, III, IV, and VI)One-step secretion systems bypass the periplasm entirely, forming a continuous channel that spans both the inner and outer membranes:Type I Secretion System (T1SS):...
1.1K