Study of the in vitro sensitivity to honey bee propolis of Staphylococcus aureus strains characterized by different sensitivity to antibiotics.

Abstract - The sensitivity level to propolis in 44 Staphylococcus aureus strains, 42 isolated from patients of hospital environment and 2 ATCC reference strains, has been studied. The strains considered showed different behaviour towards antibiotics typically used in the hospitals in order to contain both Gram positive and Gram negative bacteria. On the contrary all the S. aureus isolates studied showed sensitivity towards 2 propolis samples collected from two different areas of Piedmont (Italy). In particular it is important to underline that 11 isolates resistant to methicillin showed sensitivity to propolis. The analysis of variance calculated on values of the minimum concentration of propolis inhibiting microorganism growth did not show any significant differences to the sensitivity level to the product among the 44 isolates studied. The results obtained from the research appear to confirm the antimicrobial property of propolis and contribute to increase interest in the power of this natural product in medical field.