Genetic Evolution of Antibiotic Resistance and Virulence Genes in Escherichia coli Isolates from a Chinese Hospital over a 12-Year Period.

Escherichia coli is a significant pathogen capable of inducing a variety of infections in both human and animal hosts. Despite its clinical significance, there is a lack of longitudinal research aimed at elucidating the genomic attributes that facilitate antimicrobial resistance and clonal dissemination in this bacterium. In this study, we investigated the genetic dynamics of antibiotic resistance and virulence factors within a collection of 137 E. coli isolates retrieved from a Chinese hospital over a 12-year period. Notably, a substantial increase in resistance to various antibiotics, including broad-spectrum β-lactams, aminoglycosides, and quinolones, was observed. Additionally, our study revealed the acquisition of diverse antibiotic resistance and virulence genes across different sequence types (STs). Among the STs, ST131 emerged as the most prevalent, exhibiting a high level of multidrug resistance. In contrast, ST73 and ST12 demonstrated a higher prevalence of virulence genes, suggestive of a potential trade-off between antibiotic resistance and virulence. What's more, we identified significant intra-clonal diversification and convergence of antibiotic resistance and virulence traits within the dominant ST131 group. These findings underscore the importance of longitudinal studies in understanding the evolution of bacterial pathogens and the necessity for ongoing research to inform public health strategies.