Identification of Antibiotic-Resistance Markers of Edwardsiella Tarda Using Aptamers

Abstract

Edwardsiella tarda is an important aquaculture pathogen and antibiotic resistance in this bacterium has led to severe issues in the aquaculture industry. Therefore, identifying antibiotic-resistance markers is of great significance for the prevention and control of E. tarda. In the present study, we used tetracycline-sensitive (S) and -resistant (R) E. tarda strains, as well as six non-target bacterial strains, to obtain aptamers via the Systematic Evolution of Ligands by Exponential Enrichment technique and comparatively analyzed them based on their relative importance index values. Thereafter, we selected six candidate sequences (M1, M13, M15, N57, N69, and N71) for affinity verification. The results showed that M1 had significantly higher affinity for both the S and R strains compared to the non-target strains; M13 and M15 had significantly higher affinities for S strain compared to the R strain and non-target strains; and N57, N69, and N71 had significantly higher affinities for R strains compared to the sensitive and non-target strains. Further analysis indicated that N57 and N69 could specifically recognize unique sites in the R strain. Therefore, our study provides a novel methodology for the detection and control of antibiotic-resistant E. tarda strains and the identification of drug-resistant markers in bacteria.

Keywords: Edwardsiella tarda, Aptamer, SELEX, Antibiotic resistance-marker, Affinity, Specificity