Integrating computational approaches to uncover β-lactamase-associated resistance in diarrheagenic Escherichia coli from pediatric patients.

Multidrug-resistant diarrheagenic Escherichia coli (MDR-DEC) increasingly complicates treatment of pediatric infections, largely due to β-lactamase-mediated resistance. Despite their clinical relevance, the evolutionary diversity, functional mechanisms, and therapeutic targeting of β-lactamase enzymes in DEC remain poorly defined. This study addresses that gap by evaluating the prevalence of β-lactamase genes in DEC isolates and exploring their molecular interactions with key antibiotics. This study aims to detect and characterize β-lactamase-producing diarrheagenic Escherichia coli (DEC) isolates from children suffering from diarrhea, and to investigate the underlying drug-target interactions contributing to antimicrobial resistance. A total of 120 E. coli isolates were obtained from pediatric diarrheal, non-diarrheal, and healthy groups. Molecular screening for β-lactamase genes was performed using RT-PCR. Structural modeling, phylogenetic analysis, and molecular docking were used to evaluate evolutionary patterns and drug interactions with ceftriaxone and amoxicillin. β-lactamase enzymes in DEC strains exhibited varying thermal stability and were frequently co-produced. Molecular docking revealed that while amoxicillin had stronger binding affinity for certain enzymes, ceftriaxone demonstrated greater inhibitory potency across key targets. Resistance genes such as bla_TEM, bla_SHV, and bla_CTX-M were central in the resistance network. Additional mechanisms, including efflux pump activity and DNA repair pathways, contributed to the multidrug-resistant phenotype. This study highlights the multifactorial resistance landscape of DEC, driven by diverse β-lactamase variants and supporting mechanisms such as efflux and DNA repair. The differential drug interaction profiles of amoxicillin and ceftriaxone underscore the importance of structure-guided antibiotic selection. These insights may inform more targeted therapeutic strategies and support molecular surveillance efforts to monitor and combat MDR-DEC in pediatric settings.