الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Rapid and reliable identification of foodborne pathogenic microorganisms, including Aeromonas hydrophila, is important for prevention and control of food-borne diseases. Recently, gold nanoparticles is a popular choice for innovative colorimetric diagnostics due to their unique optical properties. In this study, we developed a novel assay for detection of A. hydrophila using gold nanoparticles oligo-probe. The study was applied on 100 Nile Tilapia samples and the results revealed that the incidence of A. hydrophila was 58 % after biochemical characterization of the isolates. Moreover, the incidence of Aeromonas spp. was 53 % according to 16S rDNA detection by PCR. While, 42% were identified as A. hydrophila according to RFLP. However, the aerolysin gene was identified in 34 % of the samples. The gold nanoparticles oligo probe assay was optimized for colorimetric detection of nearly 10.93 ng unamplified A. hydrophila DNA. When hybridization occur with target DNA containing complementary sequences remains red while, test samples without complementary DNA sequences to the colour turns purple due to acid induced aggregation of AuNP-oligo probes. The results recorded of this assay compared to the reference PCR method was nearly similar moreover, it requires less than 30 minutes after genomic DNA extraction. Accordingly, a rapid , sensitive, inexpensive and specific DNA detection technique using gold nanoprobe was effective for detection of unamplified A. hydrophila DNA from fish tissues.