RAPID AND SENSITIVE METHOD FOR THE DETECTION OF AEROMONAS-CAVIAE AND AEROMONAS-TROTA BY POLYMERASE CHAIN-REACTION

A 16S rDNA-based polymerase chain reaction (PCR) method was developed for the detection of Aeromonas caviae and Aeromonas trota. These two s pecies were identified from other Aeromonas spp. and closely related s pecies by primers set (AER1 and AER2). The amplified product was 316 b p. The identity of the amplified product was confirmed by DNA-DNA hybr idization. Two sets of primers (AER8 and AER9) were used for specific identification of Aer. caviae. Amplifying the 260 bp fragment of 16S r RNA gene region and digesting it with AluI restriction enzyme, yielded 180- and 80-bp fragments. For PCR assay, template DNA was released by mixing equal volumes of homogenized seeded crab meat with Aer. caviae and Chelex 100 (6%) incubated for 10 min at 56 degrees C followed by addition of an equal volume of 0.1% Triton-X-100 and boiled for 10 min . The detection limit was between 50 and 100 cells g(-1) of crab meat. This method is very rapid and obviates the need for DNA isolation fro m complex food matrices and is specific for detecting two Aeromonas sp ecies.