Phage-mediated aggregation of gold nanoparticles for visual detection of Vibrio parahaemolyticus

Abstract

Vibrio parahaemolyticus (V. parahaemolyticus) is a foodborne pathogen commonly found in aquatic products and water environments, necessitating effective detection strategies. Here, a lytic phage VPP1 was isolated and characterized at the biological and genomic levels. VPP1 displayed specificity for V. parahaemolyticus and stability under changing conditions. Genome sequencing of the phage VPP1 revealed a 42,445 bp DNA genome with 64 open reading frames (ORFs), lacking genes involved in pathogenicity or drug resistance. A colorimetric method for the rapid detection of V. parahaemolyticus was subsequently established using gold nanoparticles and the phage VPP1 (AuNPs@VPP1). The aggregation of AuNPs was mediated by the phage VPP1 upon capturing targeted V. parahaemolyticus. The detection process could be completed within 75 min, enabling qualitative detection using the naked eye and quantitative detection using a UV–Vis spectrophotometer. The method enabled the detection of the targeted V. parahaemolyticus within the range of 8.9 × 101 to 8.9 × 108 CFU/mL, without cross-reaction with interfering or dead bacteria. The recoveries of V. parahaemolyticus in spiked lake water and crayfish samples were 81.07 %–129.17 % and 83.78 %–129.73 %, respectively. The method also demonstrated satisfactory performance in naturally contaminated samples, achieving recoveries ranging from 90.60 % to 114.86 %. This study indicated that phage-mediated aggregation of AuNPs holds promise for the detection of pathogens in environmental and food samples.

Keywords

• Vibrio parahaemolyticus
• Phage
• Gold nanoparticles
• Aggregation
• Detection