Effect of thymol and eugenol essential oils on multi-drug resistant Uropathogenic Escherichia coli: Its relation to virulence and antibiotic resistance

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Document Type : Original Article

Authors

1 Medical Microbiology and immunology Department, Faculty of medicine, Menoufia University, Egypt

2 Medical Microbiology and Immunology Department, Faculty of Medicine, Suiz University, Egypt

Abstract

Background: Uropathogenic Escherichia coli (UPEC) remains the leading cause of urinary tract infections (UTIs), with increasing resistance to antibiotics and expression of virulence factors complicating treatment. Natural compounds, such as thymol and eugenol, offer potential therapeutic alternatives that target bacterial virulence. The study examines UPEC strains from community and hospital-acquired UTIs, focusing on antimicrobial resistance, virulence profiles, and efficacy of thymol and eugenol. Methods: A total of 267 urine samples were collected from Menoufia University Hospitals. Sixty-five multidrug-resistant UPEC isolates were identified. Antimicrobial susceptibility profile was assessed using both disc diffusion and MIC testing. Plate-based assays detected protease and curli fimbriae phenotypes. Anti-virulence effects of thymol and eugenol were evaluated using sub-inhibitory MICs. Virulence genes (crl, csgA, fimH, and bla-CTX-M15) were detected by real-time PCR. Results: HA UPEC strains showed significantly higher resistance to piperacillin, ciprofloxacin, and trimethoprim (p ≤ 0.05) than community-acquired (CA) strains. Protease production was more prevalent among hospital isolates (55.6% vs. 13.2%, p < 0.001), while curli expression was high in both groups. Thymol inhibited curli expression in 91.3% and protease in 86.7% of hospital isolates. Eugenol showed moderate inhibition.   Virulence genes were significantly more prevalent in HA strains, including bla-CTX-M (85.2% vs. 39.5%), crl (88.9% vs. 50.0%), csgA (81.5% vs. 42.1%), and fimH (74.1% vs. 47.4%). Conclusion: HA UPEC isolates exhibit greater antibiotic resistance and virulence potential than CA strains. Thymol and eugenol demonstrate promising anti-virulence activity, particularly thymol, which may serve as an effective adjunct therapy against multidrug-resistant UPEC.

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Microbes and Infectious Diseases

Articles in Press, Accepted Manuscript
Available Online from 01 July 2025

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