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International Journal of Microbiology
Volume 2009, Article ID 501362, 7 pages
Research Article

Phenotypic and Genotypic Characterization of Staphylococcus aureus Strains from Italian Dairy Products

1CNR Istituto di Scienze delle Produzioni Alimentari (ISPA), Sez. Milano, Via Celoria 2, 20133 Milan, Italy
2Veneto Agricoltura, Istituto per la Qualità e le Tecnologie Agroalimentari, Via San Gaetano 74, 36016 Thiene (VI), Italy

Received 16 March 2009; Revised 31 August 2009; Accepted 22 October 2009

Academic Editor: Dulal Borthakur

Copyright © 2009 Stefano Morandi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Staphylococcus aureus is a known major cause of foodborne illnesses, and milk and dairy products are often contaminated by enterotoxigenic strains of this bacterium. In the present study, 122 S. aureus isolates collected from different dairy products were characterised by phenotypic properties, by the distribution of genes encoding staphylococcal enterotoxins (sea, sec, sed, seg, seh, sei, sej, and sel) and by randomly amplified polymorphic DNA PCR (RAPD-PCR). Moreover, strain resistance to vancomycin and methicillin (oxacillin) was studied. The differences in the RAPD-PCR profiles obtained with the primers M13 and AP4 revealed the presence of a great genetic heterogeneity among the different S. aureus strains. Using the primer AP4 and M13, eight groups were distinguished by RAPD-PCR cluster analysis, although, except in few cases, it was not possible to correlate the isolates of different animal species (cow or ovine) with the presence of se genes. None of the isolates showed resistance to vancomycin or methicillin.