Codon usage and antibiotic resistance: A hidden evolutionary mechanism.

Antibiotic resistance represents a global health crisis, and emerging evidence suggests that codon usage, traditionally considered a silent aspect of genetic coding, plays a pivotal role in the evolution of resistance. Traditional resistance mechanisms, such as efflux pumps, enzymatic inactivation, and target modification, have been extensively studied. Still, recent findings highlight the role of codon optimization in enhancing the synthesis of resistance determinants in pathogens, including Acinetobacter baumannii, Neisseria gonorrhoeae, and Klebsiella pneumoniae. Comparative genomic analyses employing metrics such as Codon Adaptation Index (CAI), Effective Number of Codons (ENC), and Relative Synonymous Codon Usage (RSCU), alongside advanced bioinformatic and machine learning approaches, have identified subtle yet significant shifts in codon usage patterns between resistant and susceptible strains. Additionally, experimental studies using in vitro assays, in vivo models, and synthetic biology approaches prove that translational control through codon modulation contributes to adaptive responses under antibiotic pressure. Understanding these associations offers potential avenues for developing novel diagnostic biomarkers and therapeutic strategies. Therefore, this review underscores the necessity of an interdisciplinary approach to decipher the complex interplay between codon usage and antibiotic resistance, ultimately informing future efforts to mitigate the impact of multidrug-resistant pathogens.