Fast drug rotation reduces bacterial resistance evolution in a microcosm experiment

Area of Science:

• Evolutionary biology
• Microbiology
• Antimicrobial resistance

Background:

• Drug rotation (cycling) is used to limit pathogen resistance evolution.
• Current practices often involve infrequent drug alternation, expecting resistance reversion.
• The frequency of drug alternation is a critical factor in rotation effectiveness.

Purpose of the Study:

• To investigate if fast drug rotation can limit resistance evolution.
• To test the hypothesis that rapid alternation prevents population recovery and genetic diversity.
• To evaluate fast drug rotation as a strategy against bacterial resistance.

Main Methods:

• Experimental evolution using the bacterium Pseudomonas fluorescens.
• Exposure to two antibiotics: chloramphenicol and rifampin.
• Systematic variation of drug rotation frequency.

Main Results:

• Increased drug rotation frequency reduced the probability of evolutionary rescue.
• Most surviving populations exhibited resistance to both antibiotics.
• Drug resistance imposed fitness costs, independent of rotation history; early population recovery correlated with survival.

Conclusions:

• Fast drug rotation is a promising strategy to mitigate bacterial resistance evolution.
• This approach can be a viable alternative to drug combinations, especially when safety concerns exist.
• Limiting population recovery time between drug exposures is key to preventing resistance.