Antimicrobial Efficacy and Time-kill Kinetics of Phoenix dactylifera L. Seed Oil Against Multidrug Resistant Pathogens from Cancer Patients

Abstract

Infectious complications are a frequent occurrence in cancer patients, with antimicrobial resistant pathogens contributing significantly to the morbidity burden in this population. This study evaluated the antimicrobial efficacy of Phoenix dactylifera L. seed oil (PDEO) against antimicrobial resistant pathogens isolated from cancer patients. P. dactylifera seed oil was extracted via steam-distillation technique. The antimicrobial activity of the essential oil was determined using agar disk diffusion, broth microdilution and time-kill kinetics assays, while the mechanism of action was determined by quantifying ion-leakage from the microbial cells. For bacterial isolates, the zone of inhibition ranged from 14.33 ± 0.17 mm in Klebsiella pneumoniae to 31.33 ± 0.17 mm in Streptococcus pneumoniae and Staphylococcus aureus; while for fungal isolates it ranged from 13.67 ± 0.33 mm in Candida glabrata to 31.33 ± 0.33 mm in Candida parapsilosis. The time-kill kinetics of P. dactylifera essential oil revealed levels of concentration and time dependent microbicidal activity against the test pathogens. Respectively, the highest concentration of sodium and potassium ion leakage from the test organisms were observed against S. aureus (31.73 ± 0.44 mg/L) and K. aerogenes (20.00 ± 0.61 mg/L) for bacterial isolates; and against C. tropicalis (38.73 ± 0.20 mg/L; 22.70 ± 0.49 mg/L) (P≤0.05) for fungal isolates. These results provide reasonable evidence that P. dactylifera seed oil could be a veritable source of safe and effective natural antimicrobial with potential utilization in the combat against antimicrobial resistant pathogens.