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.


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.


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.


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.


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
Location: Oxford, UK
Presentation type:
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