Climate warming promotes collateral antibiotic resistance development in cyanobacteria

Area of Science:

• Environmental microbiology and public health

Background:

• Cyanobacterial blooms and antibiotic resistance are growing global threats.
• Cyanobacteria act as reservoirs for antibiotic resistance genes in aquatic environments.
• The impact of climate change on cyanobacteria-associated antibiotic resistance is poorly understood.

Purpose of the Study:

• To investigate the effects of increasing temperatures on cyanobacteria-associated antibiotic resistance evolution.
• To analyze antibiotic interactions and collateral susceptibility in cyanobacteria.
• To understand the combined influence of temperature and antibiotic combinations on resistance development.

Main Methods:

• Profiling antibiotic interactions and collateral susceptibility networks across 600 cyanobacterial strains.
• Analyzing 33 antibiotics from 50 sites in four eutrophic Chinese lakes.
• Quantifying the interactive effects of temperature and collateral resistance on resistance evolution.

Main Results:

• Antibiotic resistance levels in cyanobacteria positively correlated with antibiotic heterogeneity.
• Collateral resistance was prevalent (78.5%), widening the mutant selection window.
• Increased temperature (16°C to 36°C) significantly boosted evolvability (1.25–2.5 folds) and genotypic resistance (3–295 folds) in collateral-resistance-informed lineages.

Conclusions:

• Climate warming, combined with collateral resistance, accelerates the evolution of cyanobacteria-associated antibiotic resistance.
• Increased temperature and antibiotic switching promote the emergence of resistance mutations.
• Findings offer mechanistic insights into how climate change exacerbates antibiotic resistance in aquatic ecosystems.