Single-cell analysis reveals antibiotic affects conjugative transfer by modulating bacterial growth rather than...

Area of Science:

• Microbiology
• Genetics
• Environmental Science

Background:

• Antibiotic resistance genes (ARGs) are a major global health threat.
• Quantifying horizontal gene transfer (HGT) efficiency is complex due to environmental factors.
• Single-cell methods offer precise insights into cell-to-cell interactions like conjugation.

Purpose of the Study:

• To develop and apply a single-cell system for quantifying ARG conjugation efficiency.
• To investigate the impact of subinhibitory antibiotic concentrations on HGT.
• To differentiate the effects of antibiotics on conjugation versus bacterial growth.

Main Methods:

• Automated time-lapse imaging and analysis using a custom microfluidic chip.
• Python-based image analysis pipeline for dynamic quantification.
• Integration of experimental data with individual-based modeling.

Main Results:

• No significant change in Escherichia coli conjugation efficiency was observed across varying kanamycin concentrations.
• Recipient cells with higher growth rates exhibited increased plasmid acquisition.
• The study successfully isolated conjugation efficiency from bacterial growth dynamics.

Conclusions:

• Subinhibitory antibiotic concentrations primarily influence bacterial growth rates, not direct conjugation efficiency.
• The physiological state of bacterial cells is a key factor in plasmid acquisition.
• The developed single-cell methodology provides a robust tool for studying microbial interactions and HGT.