Molecular characterisation of Vibrio parahaemolyticus carrying tdh and trh genes using ERIC-, RAPD- and BOX-PCR on local Malaysia bloody clam and Lala
Molecular typing methods have been widely applied for many purposes. In this study, such methods were adopted as DNA fingerprinting tools to determine the origin and divergence of virulent Vibrio parahaemolyticus strains found in local seafood. Although not all strain carry virulent tdh and trh ge...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English English |
| Published: |
Faculty of Food Science and Technology, Universiti Putra Malaysia
2013
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| Online Access: | http://psasir.upm.edu.my/id/eprint/30516/1/30516.pdf http://psasir.upm.edu.my/id/eprint/30516/7/Molecular%20characterisation%20of%20Vibrio%20parahaemolyticus%20carrying%20tdh%20and%20trh%20genes%20using%20ERIC.pdf |
| Summary: | Molecular typing methods have been widely applied for many purposes. In this study, such methods were adopted as DNA fingerprinting tools to determine the origin and divergence
of virulent Vibrio parahaemolyticus strains found in local seafood. Although not all strain carry virulent tdh and
trh gene, increasing prevalence demands an effective fingerprinting scheme which can constantly monitor and trace the sources of such emerging food pathogens.
By using ERIC-, RAPD-, and BOX-PCR methods, 33
Vibrio parahaemolyticus isolates from local Malaysia bloody clam (Anadara granosa) and Lala (Orbicularia orbiculata) with confirmed presence of tdh and trh
gene were characterised, followed by determination of clonal
relatedness among virulent strains using cluster analysis and discriminatory index. This study
also involved application of Immunomagnetic Separation (IMS) Method which significantly
improved the specificity of strain isolation. Cluster analysis using Unweighted Pair Group
Mathematical Averaging (UPGMA) and Dice Coefficient shown clustering according to
isolation food source, IMS level and haemolysin gene possessed. Nevertheless, different DNA
fingerprinting methods generated different clustering at different similarity cut-off percentage,
regardless as individual or as composite dendrograms. ERIC- and RAPD-PCR composite
fingerprinting relatively shown the highest discriminatory index at following similarity cut-
off percentage: 0.68 at 50%; 0.83 at 65%; and 0.93 at 75%. Discriminatory power increased
with similarity cut-off percentage. However, result also suggested that BOX-PCR might be an
effective fingerprinting tool, as it generated three clusters with no single-colony isolate at 70%
similarity cut-off. This study not only achieved its objective to determine clonal relatedness
among virulent strains from local seafood via characterisation, but also speculated the best
possible combination of molecular typing methods to effectively do so |
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