An aptamer biosensing platform for simultaneous quantification of Vibrio alginolyticus and probiotic Bacillus subtilis in shrimp aquaculture

Abstract

Vibrio alginolyticus and probiotic Bacillus subtilis are two key bacterial species in shrimp aquaculture. V. alginolyticus is a major pathogen responsible for mass mortality events in shrimp populations, whereas B. subtilis functions as a biocontrol agent that inhibits harmful bacterial growth. Maintaining a balanced microbial environment by suppressing pathogens while promoting probiotic efficacy is crucial for ensuring aquaculture productivity and food safety, highlighting the need for efficient bacterial detection methods. Here, we engineered a biosensing platform leveraging fluorescein isothiocyanate-labeled fragment crystallizable mannose-binding lectin (FITC-FcMBL) for universal microbial glycan recognition and signal amplification coupled with aptamer-functionalized magnetic beads (Apt-MBs) for the detection of V. alginolyticus and B. subtilis, with a limit of detection of 6 CFU/mL and 4 CFU/mL, respectively. This dual-target bacterial detection approach simplifies the workflow, reduces measurement variability, and enhances practical applicability. The method, which fully exploited the high specificity of aptamers combined with the broad-spectrum recognition ability of FcMBL, was further validated using real samples, including seawater, shrimp intestines, tail muscle, and fish tissue, demonstrating its reliability and effectiveness for bacterial monitoring in aquaculture environments.