Characterization of Staphylococcus aureus from Pasteur Institute in Côte d'Ivoire: Methicillin Resistance, Reduced Sensitivity to Vancomycin, Panton-Valentine Leucotoxin and Exfoliatins.

Staphylococcus aureus, which causes various infections, particularly suppurations, expresses many virulence factors. The resistance of S. aureus to methicillin (MRSA) which can spread to vancomycin constitutes a major challenge in infectiology. The search for virulence and resistance factors is therefore of interest to better understand the mechanisms of this pathogenicity. The objectives of this study were to determine the frequency of phenotypic and genotypic (mecA, vanB) resistances, the frequency of virulence genes (eta, etb, and lukS) and to investigate the resistant strains for the presence of virulence genes. On thirty-one strains isolated from infections at the Pasteur Institute of Côte d'Ivoire, the study of susceptibility to methicillin and vancomycin was carried out by phenotypic and molecular methods. We observed phenotypic and genotypic resistance to methicillin of 41.9% and 32.3% respectively. Despite a suspicion of very high vancomycin susceptibility reduced, 25.8% by phenotypic method, the vanB gene was only found in 3.2% of strains. The prevalence of virulence genes was high with the eta gene, 96.8%, and the lukS gene 45.2%. The mecA gene was present with an eta gene in 32.3% of strains and in 9.7% with the lukS gene, however the vanB gene was not present in any strain carrying virulence factors. These results should lead to the screening of other van genes for resistance to vancomycin.