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Detection of enterotoxine B producing Staphylococcus aureus directly from milk

Abstract number: p1745

Popa  M., Codita  I., Surdeanu  M., Straut  M., Cretoiu  S., Negut  M.

Objectives: 

The aim of this study was to develop a convenient DNA extraction method and to optimise a PCR reaction in order to detect enterotoxin B producing S. aureus strains directly from milk.

Methods: 

We applied a chemical extraction method of bacterial DNA from milk samples artificially inoculated with S. aureus. A PCR based method was used for the detection of seb gene (coding for enterotoxin B) and nuc gene (coding for termonuclease). A protocol for the multiplex PCR was developed and optimized. The sensitivity of the reaction was checked by determining the minimum number of organisms·ml-1, which can be detected in the multiplex PCR and in each single PCR reaction. Amplification specificity of the seb gene was verified by amplicon digestion with restriction endonucleases.

Results: 

The specific bands for both genes in the multiplex PCR were detected in samples containing a DNA quantity corresponding to 5000 organisms·ml-1. In the same reaction, the amplicon for nuc gene was visible for as little as the DNA concentration corresponding to 1000 organisms·ml-1. The sensitivity of each single PCR reaction was similar with those of multiplex PCR reaction.

Conclusion: 

The applied DNA extraction method allowed us to obtain a good quality DNA and can be used for a direct milk extraction. Multiplex PCR reaction is a simple, rapid and reliable method for detecting enterotoxin B producing S. aureus strains from milk.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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