Multi-Drug Resistant Clinical Pseudomonas aeruginosas Inhibited by Ferula gummosa Boiss.

Background: Multi-drug resistance among Pseudomonas aeruginosa (P. aeruginosa) clinical isolates is increasing and becoming a serious problem for public health authorities worldwide.

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.