Exploring the principles behind antibiotics with limited resistance

Antibiotics that target multiple cellular functions are anticipated to be less prone to bacterial resistance. This study shows that while dual targeting is crucial, it is not sufficient in preventing resistance. Only those antibiotics that simultaneously target membrane integrity and block another cellular pathway show reduced resistance development in Gram-negative pathogens. We tested several factors that could hinder the evolution of resistance. First, de novo mutations resulted in only a limited elevation in resistance, and resistance was inaccessible through gene amplification. Second, mobile resistance genes against such antibiotics were rare in human-associated microbiomes and clinically relevant pathogens. Third, the timeframe for resistance evolution is brief, owing to the rapid eradication of bacterial populations upon toxic antibiotic exposure. We conclude that resistance mechanisms commonly found in natural bacterial pathogens provide only limited protection to these antibiotics. Our work provides guidelines for the future development of antibiotics with limited resistance.