Caracterización metabolómica de la resistencia a ampicilina en cepas de ESCHERICHIA COLI

Abstract

Currently, antibiotic resistance has become more prevalent in bacteria that have adapted to antimicrobial exposure situations, as exemplified by E. coli. The most common cause of this phenomenon is the excessive use of antibiotics in humans, animals, and self-medication. In this study, the IC50 of Ampicillin was determined in 86 strains of E. coli deposited in the Microbial Culture Collection CIBE. Strains exhibiting both susceptible and resistant characteristics to Ampicillin were characterized based on their metabolic profiles using GC-MS. The IC50 concentration, measured spectrophotometrically at 630nm, identified 33.80% of strains as susceptible at concentrations below 100 μg/ml, while 66.20% of strains were considered resistant at concentrations ranging from 100 μg/ml to 4000 μg/ml of Ampicillin. Metabolite identification was conducted on samples with susceptible and resistant profiles with the most relevant IC50 values, associating them with groups. Metabolites were extracted and identified based on the retention times of the samples run on the equipment. For susceptible strain profiles, 155 and 205 peaks were observed in the chromatograms, whereas for resistant strains, 161 and 221 peaks were observed. Principal Component Analysis was performed using XLSTAT (2024), and MetaboAnalyst 6.0 software facilitated the determination of metabolites with higher significance. In resistant profiles, three metabolites exhibited greater significance, while susceptible profiles revealed 10 significant metabolites at a significance level of p < 0.05. The "FoldChange" analysis allowed the extraction of 13 metabolites from susceptible strains and 15 metabolites from resistant strains. Among the compounds obtained, fatty acids, alkanes, amino acids, and others showed greater differences from the control group. This comprehensive analysis sheds light on the metabolic intricacies associated with Ampicillin resistance in E. coli strains, paving the way for potential therapeutic interventions.