Biochemical profiles, restriction fragment length polymorphism (RFLP), random amplified polymorphic DNA (RAPD) and multilocus variable number tandem repeat analysis (MLVA) for typing Staphylococcus aureus isolated from dairy products.

The study concerns 130 Staphylococcus aureus strains isolated from different raw-milk dairy products (122 isolates) and human samples (eight isolates). Four different typing techniques were applied: biochemical profiles (Biolog GP), restriction fragment length polymorphism of coagulase gene (coaRFLP), random amplified polymorphic DNA (RAPD) and multilocus variable number tandem repeat analysis (MLVA). Moreover multiplex-PCR was used to study the distribution of genes encoding staphylococcal enterotoxins. The results of this study reveal marked genomic and phenotypic variability among the tested S. aureus. The considered techniques were all found useful for strain typing, but, based on discriminatory power as the key parameter of the typing system, MLVA and Biolog GP were found to be the most powerful techniques. The methods showed little concordance in terms of discerning the clusters of related strains.