From the Guidelines
Horizontal gene transfer is a primary mechanism for the spread of antimicrobial resistance (AMR) among bacteria, allowing them to acquire resistance genes through transformation, conjugation, and transduction, as facilitated by mobile genetic elements such as plasmids and transposons 1.
Key Mechanisms of Horizontal Gene Transfer
- Transformation: the uptake of naked DNA from the environment
- Conjugation: direct cell-to-cell transfer via pili
- Transduction: virus-mediated DNA transfer These mechanisms enable the rapid dissemination of resistance traits across different bacterial species and genera, including the spread of resistance to macrolides, as seen in organisms like Streptococcus pneumoniae and Staphylococcus aureus 1.
Clinical Impact
The clinical impact of horizontal gene transfer is significant, as it can quickly spread resistance to last-resort antibiotics, highlighting the importance of antimicrobial stewardship and infection control measures to limit resistance spread 1.
Resistance Genes and Mobile Genetic Elements
Mobile genetic elements like plasmids and transposons often carry multiple resistance genes simultaneously, including those encoding resistance to macrolides, such as erm genes, which can confer resistance to lincosamides like clindamycin 1.
Importance of Antimicrobial Stewardship
The rising bacterial resistance rates to macrolides, as reported globally, emphasize the need for prudent use of antibiotics to mitigate the selective pressure driving the spread of resistance 1.
From the Research
Horizontal Gene Transfer Mechanisms
- Horizontal gene transfer (HGT) is a significant contributor to the spread of antibiotic resistance genes among bacteria 2, 3, 4, 5.
- HGT can occur through three main mechanisms: conjugation, transduction, and transformation 2, 4, 5.
- Conjugation involves the direct transfer of genetic material between bacteria through plasmids 2, 4, 5.
- Transduction involves the transfer of genetic material through bacteriophages 2, 4.
- Transformation involves the uptake of extracellular DNA by bacteria 2, 3, 4.
Factors Influencing Horizontal Gene Transfer
- The use of antibiotics can facilitate HGT by damaging bacterial cell walls and increasing the uptake of extracellular DNA 3, 5.
- Antibiotics can also provide selective pressure for the amplification of antibiotic resistance genes 3, 5.
- The structure and complexity of bacterial populations can influence the dynamics of HGT 4.
Implications of Horizontal Gene Transfer
- HGT can lead to the spread of antibiotic resistance genes among unrelated pathogens, making infections harder to treat 2, 5.
- Understanding the mechanisms of HGT is crucial for developing effective strategies to combat the spread of antibiotic resistance 2, 4, 5.
- Mathematical modeling can be used to study the dynamics of HGT and inform the development of interventions to control antibiotic resistance 4, 6.