Polyphenols-Rich Extracts from Pistachio (Pistacia vera L.) may be effective against some strains of Staphyloccus bacteria

Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are Gram-positive human pathogens responsible for a range of infections (skin, respiratory, and bone joint), endocarditis, bacteremia, and toxic shock syndrome. S. aureus is implicated in a variety of biofilm-related infections, including implanted medical devices and wound-associated infections.  

Biofilm formation has been reported in several human infections involving the oral cavity and the skin. Biofilms are known to be resistant to conventional antibiotics and are therefore demanding for novel antibacterial compounds that can treat this community. Since several MRSA strains have become multi-drug resistant, novel treatments are needed to treat these widespread infections.

Study and Discussion
The objective of this study was to determine the effect of pistachio polyphenol extracts from raw and roasted pistachios on strains of Stapylococcus, bacteria responsible for a range of infections, especially multi-drug resistant, methiciliin-resistant S. aureus (MRSA) strains which has become one of the main causes of deaths amongst hospital-acquired infectious diseases.

Raw and roasted pistachios were ground to a fine powder and polyphenol-rich extracts were obtained.  Samples of Staph were obtained from patients with orthopedic infections.  The samples were cultivated in a lab and treated separately with polyphenol extracts from the roasted and raw pistachios.  Cultures were observed to determine if the growth of bacteria increased, decreased or remained the same. 

Extracts from pistachios were partially active against some of the Staphylococcus bacteria and either stopped the growth of (bacteriostatic) or decreased the number of bacteria present (bactericidal).  Raw pistachios were richer in polyphenols than roasted pistachios and had greater antioxidant activity.  

The use of pistachio polyphenols in combination with traditional treatment of antibiotics could identify a novel approach of treating S. aureus infections.


Erminia La Camera, Carlo Bisignano , Giuseppe Crisafi, Antonella Smeriglio,Marcella Denaro, Domenico Trombetta  and Giuseppina Mandalari*
1 Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina,
Viale SS. Annunziata, 98168 Messina, Italy; elacamera@unime.it (E.L.A.); gcrisafi@unime.it (G.C.);
asmeriglio@unime.it (A.S.); denaromarcella.md@gmail.com (M.D.); dtrombetta@unime.it (D.T.)
2 Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali,
University of Messina, Via Consolare Valeria, 98125 Messina, Italy; cbisignano@unime.it