Selection, identification and application of a DNA aptamer against Staphylococcus aureus enterotoxin A

Abstract

In recent years, staphylococcal food poisoning (SFP) caused by the ingestion of food contaminated with Staphylococcus aureus enterotoxins (SEs) has been one of the most common foodborne illnesses worldwide. As a result, rapid, sensitive and reliable detection methods are crucial for routine observations of SEs. However, current detection methods are primarily antibody-dependent, and the development of methods is limited by the preparation and instability of fresh antibodies during testing. In this study, aptamers that bind to Staphylococcus aureus enterotoxin A (SEA) with high affinity and selectivity were generated in vitro by a twelve-round selection process based on magnetic separation technology with a dissociation constant (K_d) value as low as 48.57 ± 6.52 nM. The optimal aptamer A15 was successfully used in the fluorescent bioassay to detect SEA in the food sample with a detection limit of 8.7 × 10⁻³ μg mL⁻¹. Based on this study, the selected aptamers can be expected to be new molecular recognition elements that can be used in innovative biosensors for SEA detections.