Background: Multi-drug resistance among Pseudomonas aeruginosa (P.
aeruginosa) clinical isolates is increasing and becoming a serious problem for public health
Objective: The aim of the current study is to introduce a potent antibacterial compound
against the resistant P. aeruginosa.
Methods: In this study, we evaluated the antibacterial effects of extracts and essential oils
of Ferula gummosa Boiss (F. gummosa) on 33 P. aeruginosa clinical isolates by microdilution
method and assessed the association of antimicrobial activity with the extended spectrum
β-lactamase (ESBL) producing, biofilm forming and aliginate production of the
strains. In addition, the presence of some genes involved in these properties, including blaGES-
1, blaRER-1, blaCTX-M, blaVEB-1, blaOXA-1, blaOXA-4, blaOXA-10, ppyR, pslA, pelA, algU, algL,
algD, fliC and oxaA was determined using PCR.
Results: We revealed that all of our extracts and essential oils had significant antibacterial
effects (p<0.001), but the aqueous extracts showed a relatively lower antibacterial activity
compared with the methanolic ones. Furthermore, the minimum inhibitory concentration
required for the ESBL producing strains was significantly higher than the non-ESBL producing
ones (p<0.001). Loss of some genes such as blaPER-1, blaGES-1, blaOXA-1 and blaOXA-4
caused sensitivity to F. gummosa derivatives (p<0.05).
Conclusion: The findings of this study indicate that the antibacterial effects of the extract
and essential oils of F. gummosa may be a potential novel treatment against drug-resistant
P. aeruginosa clinical isolates.