The Effect of Citrus reticulata and Rheum rhabarbarum on Gene Expression of fimB and fimE Genes in Escherichia coli Isolates Taken from Iraqi Prostate Patients

Abstract

Citrus reticulata essential oil Rheum rhabarbarum (rhubarb) extract as herbal alternatives to conventional antibiotics in combating multidrug-resistant (MDR) Escherichia coli isolated from patients with benign prostatic hyperplasia (BPH) suffering from urinary tract infections (UTIs). A total of 120 urine samples were collected from male patients (aged 45–87), from which 29 E. coli strains were identified. Among them, six isolates (E1, E3, E9, E14, E16, and E18) showed strong antibiotic resistance and high biofilm-forming ability.C. reticulata oil exhibited strong antibacterial activity, fully inhibiting all six MDR E. coli isolates at 10,000 and 20,000 ppm, while rhubarb extract showed no inhibition.Biofilm production by the most virulent isolates significantly decreased when treated with C. reticulata oil (P ≤ 0.01).Gene expression analysis revealed that citrus oil downregulated fimE (a gene that suppresses fimbriae expression) and upregulated fimB (a gene that activates fimbriae), suggesting a dual role in modulating bacterial adhesion mechanisms.Gas chromatography–mass spectrometry (GC-MS) analysis showed that the main active compound in citrus oil was D-Limonene (76.17%), which is known for its antimicrobial properties. C. reticulata essential oil demonstrates significant potential as a natural antimicrobial and antibiofilm agent against MDR E. coli, offering a promising approach for treating UTIs in patients with BPH, especially in the face of increasing antibiotic resistance.