Evaluation of biofilm activity, virulence genes, and antibiotic susceptibility profiles in clinical Proteus mirabilis isolates

İrem Unat; Tuğrul Hoşbul

doi:10.3855/jidc.22641

Evaluation of biofilm activity, virulence genes, and antibiotic susceptibility profiles in clinical Proteus mirabilis isolates

Authors

İrem Unat Medical Microbiology Laboratory, Kelkit State Hospital, Gümüşhane, Türkiye https://orcid.org/0000-0002-9247-2480
Tuğrul Hoşbul Department of Medical Microbiology, Gülhane Faculty of Medicine, University of Health Sciences, Ankara, Türkiye https://orcid.org/0000-0002-0150-4417

DOI:

https://doi.org/10.3855/jidc.22641

Keywords:

Proteus mirabilis, virulence factors, biofilm, antibiotic resistance

Abstract

Introduction: Proteus mirabilis is a common opportunistic pathogen in wound and urinary tract infections (UTIs), whose clinical significance is driven by biofilm formation. This virulence-mediated process provides a shield against antimicrobials and host immunity, promoting difficult-to-treat infections. This study aimed to elucidate the relationship between biofilm-forming capacity, presence of virulence genes, and antibiotic resistance profiles in P. mirabilis isolates.

Methodology: A total of 76 P. mirabilis isolates from urine and wound samples were analyzed. Isolates were identified using MALDI-TOF MS, antimicrobial susceptibility was tested via VITEK®2, biofilm formation was measured using the crystal violet method, and the presence of virulence genes (ureC, ireA, zapA, rsbA, flaA, atfA, ucaA, and hpmA) was analyzed by PCR.

Results: Wound isolates showed significantly enhanced biofilm production and higher resistance rates to multiple antibiotics. Moderate-to-strong biofilm production was significantly associated with catheterization, the presence of the zapA, atfA, and ucaA genes, and increased resistance to ciprofloxacin and trimethoprim-sulfamethoxazole (TMP-SXT). The presence of the hpmA gene showed a borderline association with TMP-SXT resistance. The presence of the rsbA gene was significantly associated with a reduced likelihood of ertapenem resistance, suggesting a role in modulating porin-mediated antibiotic uptake.

Conclusions: Biofilm-mediated resistance is a significant barrier to managing P. mirabilis infections, particularly in wounds and catheter-associated UTIs. The presence of specific genes in moderate-to-strong biofilm producers indicates their products are integral to the structural integrity and the functional capacity of the biofilm. The inverse relationship between rsbA and carbapenem resistance warrants further investigation as a biomarker for susceptibility.

Author Biography

Tuğrul Hoşbul, Department of Medical Microbiology, Gülhane Faculty of Medicine, University of Health Sciences, Ankara, Türkiye

Department of Medical Microbiology, Gülhane Faculty of Medicine, University of Health Sciences, Ankara, Türkiye

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Published

2026-09-30

How to Cite

Unat İrem, Hoşbul T (2026) Evaluation of biofilm activity, virulence genes, and antibiotic susceptibility profiles in clinical Proteus mirabilis isolates. J Infect Dev Ctries 20:1351–1360. doi: 10.3855/jidc.22641

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Issue

Vol. 20 No. 09: September 2026

Section

Original Articles

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