Exploring antibiotic susceptibility and plasmid characteristics in sun-dried meat foodborne pathogens

Abstract

For this study, eight bacterial isolates from samples of sun-dried meat were employed. The isolates were identified as Enterococcus sp., Micrococcus sp., Bacillus sp., Staphylococcus auereus, Salmonella sp., Escherichia coli, Pseudomonas sp., and Klebsiella pneumonia through morphological and physiological characterisation. Acridine orange (0.75 mg/ml) was used for the plasmid curing process. Using agarose gel electrophoresis, the effectiveness of the plasmid was examined, and antibiotic susceptibility discs were used to measure the effect on antibiotic susceptibility. Pefloxacin (PEF), an antibiotic with a 75% sensitivity, was the most successful in suppressing the isolates. Conversely, all isolates were resistant to ampicillin (APX) and amoxicillin (AM), which were the least effective antibiotics. Klebsiella sp. is the most resistant isolate; it exhibited resistance to 88.8% (8 of 9) of the drugs tested. However, Staphylococcus aureus is the most responsive organism, showing sensitivity to 55.5% (5 out of 9) of the antibiotics tested. Of the eight isolates tested, five had plasmids detected in them, while three (Bacillus sp., Salmonella species, and Klebsiella pneumonia) lacked plasmids as evidenced by the absence of a visible band. Following the curing process, Micrococcus sp lost its resistance to 3 of the 9 antibiotics (33%) while Staphylococcus aureus developed its resistance to 5 of the 9 (56%) drugs. According to this study, foodborne bacteria can carry and potentially spread plasmids that confer persistent antibiotic resistance. Furthermore, it demonstrates that, depending on plasmid curing, some resistance is chromosomally mediated and some are plasmid-mediated.