Exploring Antibiotic Resistance Mechanisms and β-Lactamase Interactions with Ceftriaxone and Linezolid
Thillainayagi.M *
Department of Microbiology, Maruthupandiyar College, Vallam, Thanjavur, (Affiliation to Bharathidasan University, Tiruchirappalli, Tamil Nadu 620024), India.
Bharathidasan.R
Department of Microbiology, Maruthupandiyar College, Vallam, Thanjavur, (Affiliation to Bharathidasan University, Tiruchirappalli, Tamil Nadu 620024), India.
*Author to whom correspondence should be addressed.
Abstract
Introduction: Antimicrobial resistance (AMR) poses a significant global health challenge, fueled by mechanisms such as β-lactamase production and the formation of biofilms. This study aimed to assess antibiotic resistance, β-lactamase activity, biofilm formation, and explore resistance mechanisms through molecular docking.
Methods: Thirty-five bacterial isolates from clinical samples, representing seven genera—Escherichia coli, Salmonella spp., Staphylococcus aureus, Acinetobacter spp, Klebsiella pneumonia, Enterococcus faecalis, and Pseudomonas aeruginosa were analyzed. Antibiotic susceptibility testing determined resistance patterns, while β-lactamase production and biofilm formation were assessed phenotypically. Molecular docking evaluated interactions between β-lactamase (PDB ID: 1YLJ) and the antibiotics ceftriaxone and linezolid using Auto Dock Vina 2.0.
Results: High resistance rates were observed to ceftriaxone (85.7%) and erythromycin (71.4%). Salmonella spp. showed the highest overall resistance (77.3%) with complete resistance to ceftriaxone and cefuroxime. β-lactamase producers accounted for 25.7% of isolates, with a mean resistance rate of 67.3%, higher than non-producers. Biofilm-forming isolates (48.5%) exhibited increased resistance (68.5%) compared to non-biofilm producers (49.5%). Docking results revealed ceftriaxone had moderate binding affinity (-6.45 kcal/mol; Ki: 18.67 µM) to β-lactamase, suggesting vulnerability to enzymatic degradation, while linezolid bound more strongly (-8.66 kcal/mol; Ki: 448.07 nM), indicating better inhibitory potential.
Conclusion: These findings highlight the need for ongoing resistance monitoring, antimicrobial stewardship, and molecular-level insights to guide effective treatment against multidrug-resistant pathogens.
Keywords: Antimicrobial Resistance (AMR), β-lactamase production, biofilm formation, molecular docking, ceftriaxone, linezolid