Combining use of a panel of ssDNA aptamers in the detection of Staphylococcus aureus

Abstract

In this article, a panel of ssDNA aptamers specific to Staphylococcus aureus was obtained by a whole bacterium-based SELEX procedure and applied to probing S. aureus. After several rounds of selection with S. aureus as the target and Streptococcus and S. epidermidis as counter targets, the highly enriched oligonucleic acid pool was sequenced and then grouped under different families on the basis of the homology of the primary sequence and the similarity of the secondary structure. Eleven sequences from different families were selected for further characterization by confocal imaging and flow cytometry analysis. Results showed that five aptamers demonstrated high specificity and affinity to S. aureus individually. The five aptamers recognize different molecular targets by competitive experiment. Combining these five aptamers had a much better effect than the individual aptamer in the recognition of different S. aureus strains. In addition, the combined aptamers can probe single S. aureus in pyogenic fluids. Our work demonstrates that a set of aptamers specific to one bacterium can be used in combination for the identification of the bacterium instead of a single aptamer.

Advances in Aptamer-Based Biosensors for Food Safety

“…Staphylococcal food poisoning can cause symptoms such as nausea, vomiting, retching and abdominal cramping. Whole-bacteria subtractive SELEX was performed on Staphylococcus aureus to yield an aptamer cocktail of five sequences (Cao et al, 2009). As determined by competition experiments and flow cytometry, the sequences were effective in binding to various strains of the bacteria in a mixture.…”

reMelting curve analysis as a tool for enrichment monitoring in the SELEX process

“…Binding is then visualized and quantied by uo-rescence or chemiluminescence on a membrane by blotting 3 or on magnetic beads to perform ow cytometry for uorescence acquisition. 4,5 Other studies use radiolabeling to visualize and quantify the bound DNA. 6 Non-equilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) has proven to be a good way to control and compare SELEX fractions for target binding and even determine affinity constants (K D ) of the SELEX pools.…”

An Update on Aptamer-Based Multiplex System Approaches for the Detection of Common Foodborne Pathogens

“…Here, 11 sequences from different families were selected for further characterization by confocal imaging and flow cytometry. The Kd values obtained for a single candidate aptamer were in the nanomolar range and showed a high specificity (Cao et al 2009). Recently, combinatorial assays for simultaneous detection of three pathogenic bacteria was developed using multicolor up conversion nanoparticles (UCNPs) as luminescence labels coupled with aptamers as the molecular recognition elements .…”