Evaporation-induced hydrodynamics control plasmid transfer during surface-associated microbial growth

Area of Science:

• Microbial Ecology
• Fluid Dynamics
• Genetics

Background:

• Droplet evaporation creates micro-scale hydrodynamic flows on surfaces.
• These flows influence microbial cell distribution, impacting community development and plasmid spread.
• Understanding these processes is crucial for predicting the proliferation of antibiotic resistance.

Purpose of the Study:

• To experimentally quantify how evaporation-induced hydrodynamics affect microbial cell deposition patterns.
• To determine how these deposition patterns control the spread of antibiotic resistance plasmids.
• To link initial cell distribution patterns to plasmid transfer dynamics using modeling.

Main Methods:

• Experimental quantification of microbial cell deposition patterns during droplet evaporation.
• Investigation of the coffee ring effect and Marangoni convection.
• Utilizing an individual-based model to link deposition patterns with plasmid transfer.

Main Results:

• Plasmid spread is directly correlated with the initial density of cells deposited via the coffee ring effect.
• The relative strengths of the coffee ring effect and Marangoni convection dictate initial cell deposition patterns.
• These patterns significantly influence the extent of plasmid transfer during surface-associated growth.

Conclusions:

• Evaporation-induced hydrodynamics are key drivers of microbial cell spatial distribution.
• Initial cell deposition patterns critically control plasmid proliferation and spread.
• This study highlights the ecological impact of natural hydrodynamic processes on microbial communities and antibiotic resistance dissemination.