<b>DIFFERENTIATION BETWEEN Staphylococcus aureus, S. intermedius AND S. hyicus USING PHENOTYPICAL TESTS AND PCR</b>

Abstract

<p align="justify">The aim of this work was to compare the use of two phenotypical tests (beta-galactosidase and acriflavine sensitivity) and PCR for the coa and nuc gene sequences, for the identification of three species of coagulase positive staphylococcus (CPS): S. aureus, S. intermedius and S. hyicus. Sixty five staphylococcus isolates, previously characterized as CPS through the coagulase, thermonuclease and catalase production tests and Gram staining, were identified at species level using the beta-galactosidase production tests and sensitivity to acriflavine (7 g.mL-1). At the same time, the DNA of these isolates was extracted and amplified by PCR, using primers for the coa gene, specific for S. aureus, and for the nuc gene, specific for S. intermedius and for S. hyicus. It was possible to differentiate the three species of Staphylococcus through phenotypical tests as well as through the molecular technique. There was no difference in discriminatory power between the two techniques used, but the reproducibility and reliability of the technique based on PCR make this technique more precise.</p>

Keywords

• Staphylococcus aureus
• Staphylococcus hyicus
• Staphylococcus intermedius
• PCR
• coa gene
• nuc gene
• phenotypical identification.