Molecular identification and antimicrobial evaluation of Pistacia atlantica essential oil against multidrug-resistant Acinetobacter baumannii.

BACKGROUND: The dissemination of multidrug-resistant (MDR) bacteria significantly limits infection treatment options. Fortunately, some plant essential oils (EOs) with biologically active molecules offer a promising alternative source of antibacterial agents. Pistacia atlantica gum is one such source, known to be rich essential oils used in medicine to treat various diseases. METHODS: P. atlantica was identified molecularly. A band of approximately 600 bp was sequenced and aligned with 18 S rRNA partial sequences of 11 Pistacia species, and a phylogenetic relationship was proposed. EOs were extracted from the gum of P. atlantica and analyzed using GC-MS. P. atlantica essential oils (PAEOs) were then tested against MDR Gram-negative Acinetobacter baumannii, and the mechanism of action was further appraised. RESULTS: GC-MS data of PAEOs revealed 44 components in the oil, of which alpha-pinene was the main component (81.4%). The minimum inhibitory concentration (MIC) of PAEO was 2.5 µL/mL. After treating A. baumannii with 2.5 µL/mL of PAEO, protein leakage, phosphate, and potassium ion efflux increased in the supernatant. Furthermore, transmission electron microscopy (TEM) revealed structural damage in bacterial cells, including cell wall lysis, release of intracellular components, and subsequent cell death. CONCLUSION: PAEO demonstrated both bacterial clearance and inhibition of adhesion on Band-Aid surfaces. The results of this study support the use of PAEO as a potential alternative treatment for infectious diseases caused by MDR pathogens.