Phenotypic and Metabolic Diversity of Salmonella Isolates from Agricultural Creek Sediment

) stress, metabolic activity using isothermal calorimetry, and antimicrobial susceptibility. Isolates showed variable hydrophobicity levels of 15% to 81%. Notably, serovar Newport isolates were grouped into two distinct clusters, indicating clonal variation. Isolate 5 (serovar Typhimurium) exhibited a high degree of acid resistance, whereas isolate 4 (serovar Holcomb) was highly susceptible to alkaline and oxidative stresses, indicating isolate-specific stress tolerance. Calorimetry analysis revealed variation in peak heat flow from 49.6 to 63.0 µW across isolates. In a subset of isolates, a secondary metabolic shift was observed at 24-26 h, pointing to the fact that these strains may adapt to fluctuating environmental conditions by utilizing alternative energy sources. Most isolates were susceptible to antimicrobials tested, while isolate 4 (serovar Holcomb) showed intermediate resistance to cefoxitin (MIC = 16 µg/mL), suggesting a potential mobile β-lactamase in this isolate, linking environmental survival to antimicrobial resistance (AMR) threats. We demonstrated distinctive characteristics of Salmonella isolates from the environment and this research provides a basis for improving risk assessment and preharvest food safety strategies.