Detection of Aeromonas sp. from chicken and fish samples by polymerase chain reaction

Abstract

A polymerase chain reaction was standardized for the identification of Aeromonas sp. using primers against 16S rRNA gene and aerolysin gene. The primers used were found to be highly specific for Aeromonas sp. and did not give positive result with other bacteria including other Gram positive and Gram-negative bacteria. The minimum detection level of PCR was found to be 102 and 104 cells mL-1 incase of 16S rRNA and aerolysin gene targeted assay, respectively. Suitability of the enrichment broth (Alkaline peptone water-cephalothin, APW-C) when tested to detect Aeromonas from the spiked samples gave good results on direct usage of the broth for template preparation without any subsequent treatment. The kinetics of the spiking study indicated that a minimum of 24 h enrichment was required for the detection of Aeromonas by cultural and PCR method. Among two PCR assays detection limits achieved by PCR targeting16S rRNA gene were better than aerolysin gene PCR assay. The results were comparable to cultural method. A total of 100 samples comprising of 50 each of chicken and fish samples were screened by cultural and PCR methods for the presence of Aeromonas. Two chicken samples and three fish samples turned out to be positive by both cultural method and PCR targeting 16S rRNA. From this study it was concluded that PCR assay targeting 16S rRNA gene can be used for the rapid detection of Aeromonas from chicken and fish samples after one step enrichment in APW-C. © Academic Journals Inc.