Section : Research Article

Published Date : Mar 28,2015

Lede

Biochemical and PCR Assay for Detection of Pathogenic Bacteria at Shrimp and Shrimp Farms in Bangladesh

Abstract

The study was conducted to detect faecal coliforms and pathogenic bacteria in shrimp and shrimp farms. Although coliforms are widely distributed in the environment, but only a small percentage are pathogenic to humans. The presence of pathogenic bacteria in shrimp causes several waterborne infections in humans that are worldwide concerning issues. In order to better determination of the health risks that are associated with the exposure to pathogenic bacteria, a multiplex PCR system was used for the rapid detection of pathogenic Aeromonas sp., Clostradium sp., Listeria sp., Salmonella sp., Shigella sp., Vibrio sp. and Staphylococcus sp. in the water, sediment and shrimp. The target genes were chosen for this investigation included: Aer gene for Aeromonas sp., hilA gene for Salmonella sp., virA gene for Vibrio sp., Sec gene for Staphylococcus aureus, neurotoxin gene type A, B, E, F for Clostridium botulinum, internalin gene for Listera sp. andipaH gene for Shigella sp. Seven pairs of specific primers were used to amplify internal fragments of these genes by PCR to generate PCR products that could be analyzed and confirmed with relative ease by gel electrophoresis. The presence of Aeromona and Vibrio sp. were found in the water, sediment as well as in the shrimp that were dominant among other bacteria species. On the other hand, Salmonella and Clostridium group was found in the sediment of one sample but there is no evidence of Listeria, Staphylococcus and Shigella group in the farms. All of the samples contained relatively large number (1100 to ≥2400 cfu/g) of coliform bacteria. The unhygienic condition and polluted water source could be the major reasons for the occurrence of these types of pathogenic bacteria in the shrimp farms in this area. The result revealed that the PCRbased rapid detection system described in this study is a powerful method for routine monitoring and risk assessment of water quality in the shrimp farms and could be an effective tool for disease studies in our shrimp sector.