Twelve rounds of selection were performed; each comprised a positive selection step against viable S. typhimurium or S. eneritidis and a negative selection step against heat killed S. typhimurium or S. eneritidis and a mixture of related pathogens, including Salmonella enteritidis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Citrobacter freundii to ensure the species specificity of the selected aptamers.

Based on the obtained aptamers, electrochemical sensors were made to detect salmonella (pubs.acs.org) and determine their type (pubs.acs.org). A method for determining the antibiotic resistance of salmonella S. enteritidis and S. typhimurium using DNA aptamers was developed, which is based on the ability of aptamers to bind only to living bacteria (Patent RU 2518372). It was found that a mixture of synthetic DNA aptamers to S. enteritidis and S. typhimurium inhibits the growth of bacterial colonies by more than 70% (pubs.acs.org).